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        IND - Enhanced, programmable command files for TOPS20
       =======================================================



                                 NOTE

               This document describes the IND program,
               a  utility which offers advanced command
               file facilities.  IND will  process  all
               standard  EXEC  "TAKE" files, as well as
               offering extra  features.   It  is  thus
               easy   to   start  to  use,  and  offers
               powerful tools for those  who  have  the
               time the find out about them.
	IND - Enhanced, programmable command files for TOPS20          Page 2




                                 NOTE

               The copyright in  the  computer  program
               described  in  this  document and in the
               associated  user  instructions  is   the
               property    of    Kevin   Ashley.    The
               information in this document is  subject
               to  change without notice and should not
               be construed as a  commitment  by  Kevin
               Ashley,  who  assumes  no responsibility
               for any errors which may appear in  this
               document.   The  software  described  in
               this  document  is  supplied   under   a
               licence  and  may only used or copied in
               accordance with the conditions of such a
               licence.   The  licence conditions state
               that this  software  shall  be  supplied
               free  of charge and shall not be sold or
               otherwise disposed of by means of  trade
               or  ortherwisw for any form of profit or
               advantage.   Possesion  or  use  of  the
               software  shall  be deemed as acceptance
               of the conditions of  the  licence.   No
               guarantee  is given or may be implied as
               to the adequacy of the  program  or  its
               suitability  for  any particular purpose
               and no liability  is  accepted  for  any
               loss or damage arising out of its use.
	IND - Enhanced, programmable command files for TOPS20          Page 3
OVERVIEW


1.0  OVERVIEW

        IND is a program which offers command  file  facilities  which
are  a  far more powerful, yet totally compatible superset of standard
TOPS20 EXEC TAKE files.  The extra facilities offered by  IND  include
the following:

        o       Labels, GOTOs, and subroutines (GOSUB, RETURN)
        o       Variables which are set at execution time
        o       Logical, numeric and string comparisons
        o       Conditional execution of commands
        o       Interaction with the user via special  question/answer
        directives
        o       Ability to create data files
        o       Ability to read input data files
        o       Creation of terminal log files recording  the  command
                file session, in a similar manner to PHOTO.
        o       Picking up of parameters for the command file from  an
                EXEC command line
        o       Ability to test such things as user name,  privileges,
        etc.
        o       Date handling, with conversion of  string  to  numeric
        dates, and vice versa

        IND   was   inspired   directly   via   its   RSX-11M/D/M-PLUS
counterpart,  also  known  as  IND, ICP or AT.  Its general syntax and
functionality owes everything to its forebear, but advantage has  been
taken  where  possible  of  extra  features that can be offered to the
TOPS20 user that would not be feasible under RSX.  Similarly, features
provided under RSX which are of little use, or are meaningless in, the
TOPS20 environment have been removed in IND-20.
	IND - Enhanced, programmable command files for TOPS20          Page 4
INTRODUCTION


2.0  INTRODUCTION


        An indirect command file (also known as TAKE file) is  a  file
containing  a  set  of  commands  for  the  TOPS20 EXEC that you would
normally type at a terminal.  In addition, it can also contain special
commands  that  allow you to control the execution of the command file
itself.  To initiate an IND file, type IND followed by the name of the
command file to the TOPS20 prompt.  If your system has a PCL EXEC, you
may also find that you can run a command file by typing CMD  filename.
This is usually much easier, as it permits you to use recognition (ie,
pressing the escape key to fill out the filename).

@IND CONTROL

        The assumed file type is  .CMD,  thus  the  preceding  command
causes further commands to be taken from CONTROL.CMD .  For other file
types, specify the file type explicitly.  An indirect command file can
contain  any  EXEC  command that you could type at your terminal (with
the exception of LOGOUT or BYE.) It may also contain commands to other
programs  that  it  runs.   Thus, the simplest type of command file is
merely a sequence of commands to the EXEC and  to  programs  that  are
run.   For  example, a command file to compare two files and print the
differences might look like this:
FILCOM
OUT.SCM=INPUT1.FIL,INPUT2.FIL
^C
PRINT OUT.SCM/DELETE

        This   simply   runs  the  FILCOM  program,  produces  a  file
consisting of the differences between two other files, and prints  the
output.   If the above commands were in a file called F.CMD, you would
run them like this:
                    @IND F
        However, this command file is very limited.   Although  it  is
already  more  powerful than an ordinary command file (which could not
contain commands to the FILCOM program), it still is not very  useful.
The  filenames  used are fixed - it might be nice to set them up as we
run the command file.  Also, we might not want to print the output if,
after we run FILCOM, we see that it is not worth printing.  IND allows
you to do  all  this,  and  more.   This  is  where  the  special  IND
directives come into their own.         Command  files  can be nested,
ie can invoke other command files, up to a current limit of 4 deep.
        When the end of the highest level file is reached, the message

@ <EOF>

is displayed on the screen.  To exit from a command file  prematurely,
type  CTRL/Z  in  response  to any request for input from IND, or type
CTRL/A while IND is running.  If you use CTRL/A, any output  that  was
being  produced  will  probably  have disappeared.  You should only do
this if it is really necessary..

                When processing a command file IND  first  reads  each
line  to  determine  if it is a command intended for TOPS20, a special
directive to IND itself, or just a message to be typed on the  screen.
	IND - Enhanced, programmable command files for TOPS20          Page 5
INTRODUCTION


The  directives  to IND are distinguished by a period (.) as the first
character in  the  line.   TOPS20  commands  have  no  special  prefix
characters.   Messages  to  the  user are prefixed by a semicolon (;).
The directives to IND form a primitive language, which allows you to:

        o Define labels
        o Define and assign values to symbols of  5  types:   logical,
        numeric,
        floating point, string and file.
        o Create and access data files
        o Control the logical flow of the command file
        o Perform logical tests
        o Enable or disable any of a number of operating modes
        o Increment or decrement numeric symbols
        o Control execution of subsidiary tasks or programs.

        The IND directives are listed below by category.   A  detailed
description  of  each  directive is presented in alphabetical order in
the next section.
	IND - Enhanced, programmable command files for TOPS20          Page 6
DIRECTIVES (SUMMARY)


3.0  DIRECTIVES (SUMMARY)


Label definition:

 .label:                Assigns a name to a line in the  command  file
                so that the line may be referenced.

Symbol definition:

 .ASK           Defines or redefines a logical symbol  by  asking  the
                user  a  Y/N question and assigns the logical symbol a
                true or false value.

 .ASKN          Defines or redefines a numeric symbol  by  asking  the
                user  a  question  and  assigns a numeric value to the
                symbol.

 .ASKR          Defines or redefines a floating point symbol by asking
                the user a question and assigns a floating point value
                to the symbol.

 .ASKS          Defines or redefines a string  symbol  by  asking  the
                user  a  question and assigns the symbol a value which
                is a string of text.

 .ASKF          Defines or redefines a file symbol  by  prompting  the
                user  for  a  filename  and associates the symbol with
                that filename.

 .FILE/.LOGICAL/.NUMERIC/.REAL/.STRING  Allow you to  declare  symbols
                and  their  types in advance of use, and initialize to
                default values.

 .PARSE         Breaks  a  string  into  substrings  by  looking   for
                specific characters that break up the string.

 .CODE          Gets the ASCII value of a character.

 .TRIM/PAD      Remove or add trailing blanks or tabs from a string.

 .RAISE/.LOWER          Makes strings upper or lower case.

 .SETT/.SETF    Defines or redefines a logical symbol and assigns  the
                symbol a true or false value.

 .SETN          Defines or redefines a numeric symbol and assigns  the
                symbol a numeric value.

 .SETR          Defines or  redefines  a  floating  point  symbol  and
                assigns the symbol a floating point value.

 .SETFI         Defines or redefines a file  symbol  and  assigns  the
                symbol a file value.

 .SETS          Defines or redefines a string symbol and  assigns  the
	IND - Enhanced, programmable command files for TOPS20          Page 7
DIRECTIVES (SUMMARY)


                symbol a character string value.

 .PURGE         Removes the definition of a symbol or set of symbols.

 .RADIX         Sets the current radix for reading in  whole  numbers,
                and for outputting them.

Date handling:

 .DAYTON        Converts a date string in a fairly arbitrary format to
                a Smithsonian day number.

 .NTODAY        Converts a Smithsonian day number to a date in text.

File access:

 .DATA          Specifies a single line of  data  to  be  sent  to  an
 output file.

 .CLOSE         Closes an output data file.

 .READ  Reads a line  of  data  from  an  input  file  into  a  string
                variable.

 .CLOSEI        Closes an input file.

 .OPEN          Opens an output data file (creates a  new  version  if
 necessary).

 .OPENA         Opens an existing output data file and appends data to
 it.

 .OPENI Opens an input file.

 .REWIND        Rewinds an input file to start of file.

 .POSITION              Positions an input file to a specific byte  in
                the file.

Logical control:

 .CALL          Invokes another IND file, keeping all symbols defined.

 .GOSUB         Branches to a label identifying  a  subroutine  within
                the command file.

 .GOTO          Branches to a label within a command file.

 .RETURN                Effects an exit from a  subroutine  -  returns
                control  to  the line following the .GOSUB that called
                it.

 .RUN           Runs a program, but allows input for  the  program  to
                come from the terminal rather than the command file.

 .TELL  Places a single command in the input buffer of a  program  run
	IND - Enhanced, programmable command files for TOPS20          Page 8
DIRECTIVES (SUMMARY)


                by      the .RUN directive.

 .EXIT          Terminates IND without a message.

 .STOP          Terminates the current command file.

 .LOGFILE       Specifies a file to be used to log terminal I/O to.

 .ENDLOG        Closes a logfile and releases pseudo terminal.

Logical tests:

 .IF            Determines whether or not a string or  numeric  symbol
                satisfies one of a number of possible conditions.

 .IFDF/.IFNDF   Determines whether or not a symbol is defined.

 .IFT/.IFF      Determines whether a logical symbol is true or false.

 .TEST          Tests the length of a string symbol,  and  checks  for
                whether it      is    alphabetic,    alphanumeric   or
                numeric.

 .TESTFILE      Tests to see if a file exists.

Enable/disable operating mode:

 .DISABLE/.ENABLE       Turns on  or  off  the  following  parameters:
                Substitution,  command  echoing,  data  mode, extended
                EXEC,  trace,   CTRL/Z   recognition,   execution   of
                COMAND.CMD,  logging  to  PHOTO-type  file, ability of
                lower fork to logout job.

 .DELIM         Changes the character used for substitution.

Loop control:

 .INC           Increments the value of a numeric symbol.

 .DEC           Decrements the value of a numeric symbol.

Execution control:

 .DELAY         Delays further execution for the specified  number  of
 seconds.

 .PAUSE         Stops the indirect command file temporarily,  allowing
                the user to enter commands to TOPS20.

Miscellaneous:

 .DISPLAY       Displays  a  string  symbol  without  translation  and
                without  leading/trailing  cr/lfs.   Useful for screen
                control.

 .STATUS                Dumps the symbol table and various performance
	IND - Enhanced, programmable command files for TOPS20          Page 9
DIRECTIVES (SUMMARY)


                counts  to the screen.

 .DDT           Merges DDT and causes an unsolicited breakpoint.
	IND - Enhanced, programmable command files for TOPS20         Page 10
SYMBOLS


4.0  SYMBOLS


        The indirect command  file  processor  allows  you  to  define
symbols.   These  symbols  can  then be tested or compared in order to
control flow through the command file.  They may also  be  substituted
for  EXEC  commands, data to files, or comments to be displayed at the
terminal.  The word 'symbol' is used interchangeably with  'variable'.
They  mean  the  same thing.  If you are used to programming languages
like FORTRAN or BASIC, you will probably find it easier  to  think  of
these  things  as  variables.   The essential concept is that they are
names for numbers or sets of characters that have  been  read  from  a
terminal or file, or produced by combining other such sets of things.
        Symbol names are strings of characters from 1 to 9  characters
in  length.   They  must  start with a letter(a-z) or dollar sign ($).
The remaining characters must be alphanumeric or dollar.  There are  5
symbol types:

        o       Logical
        o       String
        o       Numeric
        o       Real or floating point
        o       File

A logical symbol has either a true or false value.

A string symbol has as its value a string of ASCII characters, with  a
length between 0 and 120 characters inclusive.

A numeric symbol can have a value in  the  range  -131070  to  +131069
inclusive.

A floating point or real symbol  has  as  its  value  a  real  number,
ranging  through  the  permissible  range  for  single  precision real
numbers on the DEC20 (about +/- 10E+/-39).

A file symbol has as  its  value  a  TOPS20  filespec,  including  any
optional protection value, account string, etc.

        A symbol's type (logical, numeric, etc.) is determined by  the
first  directive  that  assigns a value to it.  Subsequent assignments
may change the symbol value, but cannot redefine its type.  A variable
may  also  be  declared  and  initialized by a .FILE, .NUMERIC, .REAL,
.LOGICAL or .STRING directive.  If a  variable  is  removed  with  the
.PURGE  directive,  then  its type and value are forgotten.  It may be
redefined with a new type.




4.1  SPECIAL SYMBOLS


        IND automatically defines certain special symbols dependant on
system  characteristics  and enquires made by the command file itself.
As with ordinary symbols, special symbols can be of any  of  5  types,
	IND - Enhanced, programmable command files for TOPS20         Page 11
SYMBOLS


and can be compared, substituted, and tested.  All system symbols have
a common format;  angle  brackets  (<>)  enclose  the  special  symbol
names.

Symbol name     Type                    Value

<STRLEN>        Numeric         Length of last string symbol in  .TEST
                                directive,  or  entered in response to
                                .ASKS.
<SYSTEM>        String          Name  of  system  as  printed  when  a
                                CTRL/C is struck to login, eg
                      Installation test system,TOPS20 Monitor 4(3417).
<DATE>          String          Current date in form 25-Dec-81.
<TIME>          String          Current time in form 13:00:00
<USER>          String          User name of current job, eg T-BENN
<DIRECTORY>     String          Currently  connected  directory,  with
                                structure,eg PS:<K-LIVINGSTONE>
<FILESTAT>      Numeric         Result of last .TESTFILE directive.
<EOF>           Logical         Set to TRUE if  currently  open  input
                                file   is   at  end  of  file.   False
                                otherwise, or if  no  input  file  has
                                been selected.
<ACCOUNT>       String          Account in  use  by  the  job,  as  in
                                DOCAS.
<ALPHA>         Logical         Set by  the  .ASKS,  .TEST  and  .READ
                                directives  to true if the last string
                                processed  by  them   contained   only
                                alphabetic characters.
<ALPHANUM>      Logical         As <ALPHA>, except that this  variable
                                tells    you   if   the   string   was
                                alphanumeric or not.
<DISKUSED>      Numeric         Equal to the  total  number  of  pages
                                used   in   the   currentLY  connected
                                directory.
<JOB>           Numeric         Job number
<LIQUOTA>       Numeric         Working storage quota  (in  pages)  of
                                currently connected directory.
<LOQUOTA>       Numeric         Permanent storage quota.
<NUMERIC>       Logical         Set to true if  last  string  read  by
                                .ASKS,  .TEST  or .READ contained only
                                numeric characters.
<TERLEN>        Numeric         Terminal length in lines/page
<TERMINAL>      Numeric         Controlling terminal number of current
                                job  NOTE:   this  is decimal, whereas
                                TOPS-20 has them in octal.
<BYTEPOS>       Numeric         Current position of input file  opened
                                with .READ directive, as the number of
                                the next byte which will be  read,  or
                                -1  if  no  file  is  open.   Used  in
                                conjunction with .POSITION.

<TERWID>        Numeric         Width in characters/line of terminal

<FILDEV>,<FILDIR>,              These symbols are all set by the TESTFILE
<FILNAM>,<FILTYP>,              directive to indicate the device, directory
<FILGEN>,<FILPRO>,              name, type, generation, protection, account
	IND - Enhanced, programmable command files for TOPS20         Page 12
SYMBOLS


<FILACT>,<FILCRE>,              and date/time of creation and read of the
<FILRED>                        specified file. They are all string symbols.

<FILPAG>,<FILSIZ>,              These are also set up by the .TESTFILE
<FILBYS>                        directive with the number of pages, bytes,
                                byte size of the file, if it is online. They
                                are numeric symbols.



        Other special symbols can  be  set  up  by  the  command  that
invoked  IND itself.  It is possible to pass parameters to the command
file by including them after the command file name, as below:
@IND indgen filename <This is a complex parameter> 3

        These set upto 9 parameters called P1 to  P9,  which  are  all
text  string variables.  If a parameter is not supplied on the command
line, its associated variable will be null (eg in the  above  example,
P4  to  P9  will  be  the  null  string.)  The  parameters are usually
separated by spaces, but if you wish to include special characters  or
spaces  in  a parameter, you can emclose that parameter in any sort of
brackets:  curly, round, angle or square to delimit it,  as  has  been
done  above.   You  can  also use double quotes to delimit the string.
Using one quoting mechanism allows you to use any of the others within
the  string,  without  their  having a special meaning (so you can use
unbalanced curly brackets within round brackets,  for  instance.)  The
brackets  are removed by IND before assigning the whole text string to
one parameter.  Note that you can pass numbers or filenames  this  way
too,  you  just  need  to  perform an assignment statement within IND.
Following the above example:

.setn PASSES 'p3'

will set the value of numeric variable passes to 3, as  that  is  what
the text string for p3 expands to.





4.2  SYMBOL Value Substitution


        Substitution can occur in any line of a command file.  Command
files  can  use  the  values assigned to string,numeric,file or system
symbols by replacing a normal  parameter  (for  example  a  device  or
directory name) with a symbol name enclosed in apostrophes (eg CONNECT
'dir').  As long as a previous directive has not disabled substitution
(the  .DISABLE  SUBSTITUTION  directive), IND replaces the symbol name
and apostrophes with the value of the symbol.
                When IND  encounters  an  apostrophe,  it  treats  the
subsequent  text  upto  the  next  apostrophe  as  a  symbol name, and
substitutes the value of  that  symbol  for  its  name  and  enclosing
apostrophes.
        For example, the first 2 lines below appear in a command file.
When  IND encounters these lines, it displays the following 2 lines at
	IND - Enhanced, programmable command files for TOPS20         Page 13
SYMBOLS


the controlling terminal:

 .ASKS tapname Name of magtape to read ?
mount tape 'tapname':  /write-protected/label-type:ANSI

* Name of magtape to read ?  [S]:  ARCHIVE              <- user  typed
ARCHIVE
@mount tape ARCHIVE:  /write-protected/label-type:ANSI

        ARCHIVE was entered in response to the question.   This  reply
associated  the  string  value ARCHIVE with the string symbol tapname.
Then, when IND read:

        mount tape 'tapname':  ...

it substituted for 'tapname' the value  assigned  to  TAPNAME,  namely
ARCHIVE.   If substitution mode was disabled, the command would simply
have been passed as it stood, with apostrophes.

        If apostrophes are an inconvenient character for  you  to  use
(perhaps  you  are  writing  a set of commands for a program that used
apostrophes itself), you can change the special substitution character
with the .DELIM directive.




4.3  Numeric,real And String Symbols.


        A numeric symbol is a string of digits representing a value in
the  range  -131070  to +131069.  When a numeric symbol is substituted
into text, these digits  are  placed  there,  with  a  minus  sign  if
necessary.   The  current  radix (set by the .RADIX operator) controls
what radix is used to substitute the values and read in new ones.  The
default  radix  is  10.   A numeric symbol or constant may be combined
with other symbols or constants in numeric expressions via  arithmetic
operators.  These are + to add, - to subtract, * to multiply, and / to
divide.  No imbedded blanks or tabs are allowed  in  the  expressions,
and  all arithmetic is done on whole numbers only, without a check for
under- or over-flow.  The  expressions  are  evaluated  from  left  to
right, stricly, unless parentheses are used to to form subexpressions.
For example, the directive lines:

        .SETN N1 2
        .SETN N2 3
        .SETN N3 N1+N2*4

        assigns n3 the value 20 whereas the lines

        .SETN N1 2
        .SETN N2 3
        .SETN N3 N1+(N2*4)

        assigns N3 the value 14.
	IND - Enhanced, programmable command files for TOPS20         Page 14
SYMBOLS


        Numeric expressions are permitted as second operands in  .SETN
 and  .IF  directives, and also as range arguments to .ASKN and .ASKS,
 and also
as substring delimiters in string expressions.
        Real symbols take on floating point values, such as  -232.045.
They  behave  much  the  same  as numeric symbols, in that they can be
combined in expressions.  Real and numeric symbols can be used in  the
same expression, and one is converted to the other whenever necessary.
If the final result is to be real, all integers in the expression  are
converted  to real first ;  if the final result is to be integer, each
real is rounded (in the ALGOL sense)  to  the  nearest  integer  value
before use.



4.4  String Symbols, Substrings And Expressions


        A string constant is a  string  of  any  printable  characters
(possibly including several non-printable ones, such as bell) enclosed
by quotes (" ").  Empty strings are also  permitted.   The  number  of
characters in a string cannot exceed 120.  Examples:

        "ABCDef"
        ""

        String symbols may have a value of any string  constant.   The
value  is  assigned  by  a .SETS or .ASKS directive.  For example, the
directive lines

        .SETS S1 "ABCDEF"
        .SETS S2 S1

assigns string symbol S2 the value of S1 (that is, ABCDEF.)

        A substring facility allows you to extract a segment from  the
value  of  a  string  symbol.   You  can use substrings only as second
operands in .SETS and
 .IF directives.  For example, the directive lines

        .SETS S1 "ABCDEF"
        .SETS S2 S1[1:3]

assign string symbol S2 the value of string  symbol  S1  beginning  at
character  1  and  ending  at character 3 (that is, ABC).  The top and
bottom of the range need not be numeric constants ;  they can  be  any
arbitrary numeric expression.

        You can combine a string constant, symbol  or  substring  with
another   string   constant,   symbol   or  substring  by  the  string
concatenation operator + to form a string expression.
        String expressions are permitted as second operands  in  .SETS
and  .IF  directives  where the first operand is a string symbol.  For
example, the directive lines

        .SETS S1 "A"
	IND - Enhanced, programmable command files for TOPS20         Page 15
SYMBOLS


        .SETS S2 "CDEF"
        .SETS S3 S1+"B"+S2[1:3]

assign string symbol S3 the value of the concatenation of  the  string
symbol  S1,  string constant "B", and the first 3 characters of string
symbol S2 (that is, ABCDE).
	IND - Enhanced, programmable command files for TOPS20         Page 16
DIRECTIVES


5.0  DIRECTIVES


        Directives must be separated from  their  arguments  and  from
EXEC  or program commands by at least one space or tab.  Spaces may be
placed anywhere in a command line  without  problems,  except  in  the
following exceptions:

        (1) No space is permitted between a label  and  the  following
        colon (:).
        (2) Embedded spaces or tabs are not permitted  within  numeric
        or string
         expressions (except, of course, within string constants.)

        Note specifically that the dot in front of a directive may  be
separated from its name, to allow you to indent portions of your file.
Thus, constructions like:
.             ASK fred What do you want ?
are permissible.  Similarly,
                .ASK fred What do you want ?
is equally ok, as long as leading spaces have not been  disabled  with
the
.DISABLE LEADING
directive.  (RSX and RT11 IND do  not  permit  leading  spaces  before
directives.)




5.1  Define A Label                                   .label:


        Labels always appear at the beginning of a line;  they may  be
on a line with additional directives and/or an EXEC command, on a line
with a comment, or on a line by themselves.  When control is passed to
a  line  with  a label, the line is processed from the first non-blank
character after the colon.
        Labels are upto 9 characters long, and must be preceded  by  a
period and terminated by a colon.  Once a label has been seen once, it
is found very quickly when subsequent references to it are made.  If a
label  is  referenced  before  it  is seen, there can be a short delay
while it is found.




5.2  Ask A Yes/No Question And Wait For A Reply                      .ASK


        The .ASK directive prints a question  on  the  terminal  which
requires  a  yes/no answer and sets a specified logical symbol to true
or false, depending on the reply.  Format:

        .ASK ssssss question-text

where:
	IND - Enhanced, programmable command files for TOPS20         Page 17
DIRECTIVES


        ssssss  = 1-9 character symbol to be assigned true/false value
        question-text = any ASCII string of characters, maximum length
        80

        When executing a .ASK directive,  IND  displays  the  question
preceded by an asterisk and suffixed with "[Y/N]:".  Three answers are
recognised:

        (1) YES (or an abbreviation) - set symbol to true
        (2) NO (        ""      "" ) - set symbol to false
        (3) Return on its own - treat as NO.

        Example:  The directive line

        .ASK exp Do you want to expunge the directory?

        displays

* Do you want to expunge the directory ?  [Y/N]:

on the terminal.  Symbol EXP will be set to true or  false  after  the
user  types  Yes,  no,  or  return.   Recognition  can  be used, and a
question mark typed to see the list of available options.




5.3  Ask For Definition Of A Numeric Symbol                     .ASKN


        The .ASKN directive prints on the terminal  a  request  for  a
numeric  value, waits for it to be entered, optionally tests the range
of the numeric response and/or applies a default value, and  sets  the
value of the specified symbol accordingly.  Format:

        .ASKN sssss question
        .ASKN [low:high] ssss question
        .ASKN [low:high:default] ssss question

where   sssss   =       1-9 character symbol to be assigned a  numeric
        value
        question =      question to be asked the user
        low:high =      numeric   expressions    to    indicate    the
                        permissible   low  and  high  limits  for  the
                        reponse.
        default =       numeric expression for the default answer.

        When  executing  the  directive,  IND  displays  the  question
preceded  by  *  and followed by [#]:  to indicate a numeric answer is
required.  If ranges have been specified, the display is  followed  by
[#  R:low:high]:   ;if  a  default  has  been supplied, the display is
suffixed by [# R:low:high D:def]:.
        If the user's response is out of range, IND  prints  an  error
message and re-issues the question.  If the response is an empty line,
and a default has been supplied, the default is used.  A question mark
can  be  typed  for  help,  and  escape can also be used to obtain the
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default answer, if any.  Example:

        .ASKN [1:100:20] NUSE Maximum number of users

        displays on the terminal as

        * Maximum number of users [# R:1:100 D:20]:

        The user must enter a number between 1 and 100, or type return
for 20.  Symbol NUSE is set to the returned value.




5.4  Ask For Definition Of A Real Symbol                     .ASKR


        The .ASKR directive prints on the terminal  a  request  for  a
floating point value, waits for it to be entered, optionally tests the
range of the numeric response and/or applies a default value, and sets
the value of the specified symbol accordingly.  Format:

        .ASKR sssss question
        .ASKR [low:high] ssss question
        .ASKR [low:high:default] ssss question

where   sssss   =       1-9 character symbol to be assigned a  numeric
        value
        question =      question to be asked the user
        low:high =      numeric   expressions    to    indicate    the
                        permissible   low  and  high  limits  for  the
                        reponse.
        default =       real expression for the default answer.

        When  executing  the  directive,  IND  displays  the  question
preceded  by  *  and followed by [#]:  to indicate a numeric answer is
required.  If ranges have been specified, the display is  followed  by
[#  R:low:high]:   ;if  a  default  has  been supplied, the display is
suffixed by [# R:low:high D:def]:.
        If the user's response is out of range, IND  prints  an  error
message and re-issues the question.  If the response is an empty line,
and a default has been supplied, the default is used.  A question mark
can  be  typed  for  help,  and  escape can also be used to obtain the
default answer, if any.  Example:

        .ASKR [.00001:.005:.0001] TOLERANCE Tolerance factor to use

        displays on the terminal as

        * Tolerance factor to use [# R:1E-5:0.005 D:0.0001]:

        The user must enter a number between .00001 and .005, or  type
return  for  .0001.   Symbol  TOLERANCE  is set to the returned value.
Note that  the  value  .00001  has  been  displayed  as  1E-5  -  this
conversion  to  scientific  notation  will  occur if the number is too
large or small to be conveniently displayed another way.
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5.5  Ask For Definition Of A String Symbol                              .ASKS


        The .ASKS directive prints on the terminal  a  request  for  a
string  value  to  define  a  string  symbol, and optionally tests the
number of characters in  the  string  to  ensure  they  are  within  a
specified  range.  An indication is returned to the command file as to
whether the entered characters were all alphabetic or alphanumeric  or
numeric.    This  is  via  logical  variables  <ALPHA>,<NUMERIC>,  and
<ALPHANUMERIC>.  The count of the number of characters in  the  string
is returned in variable <STRLEN>.  Formats:

        .ASKS sssss question
        .ASKS [low:high] sssss question

        where:  sssss = 1-9 character symbol name
                question = question to be displayed
                low:high = inclusive limits for number  of  characters
                in string.

        Low and high are arbitrary numeric expressions.

Examples:

        .ASKS [1:39] NAM Please enter your name

        displays

* Please enter your name [S R:1:39]:

on the controlling terminal.  The symbol NAM is defined  according  to
the answer given.  A question mark can be typed for help, although the
help message is just "text string".

        If it is desired to have a  default  for  this  function,  the
symbol <STRDEF> may be set to the default desired, ie with a directive
like:
.SETS <STRDEF> "Weekend"
will cause the string "Weekend" to be used as the default  answer  for
all .ASKS directives.  To remove the default for later directives, use
.PURGE to remove the <STRDEF> symbol.




5.6  Ask For Definition Of A File Symbol                              .ASKF


        The .ASKF directive prints on the terminal  a  request  for  a
file  specification  to define a file symbol, and optionally applies a
default generation to ensure that the file is new or old.  Formats:

        .ASKF ffff question
        .ASKF [gen] ssssss question

        where:  sssss = 1-9 character symbol name
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                question = question to be displayed
                gen = default generation number, with certain  special
                defaults.

        Gen is an arbitrary numeric expression.  It is the  generation
        number  desired  if  it  is  positive,  or  if  it  is zero or
        negative, the following rules apply:
        0 means use the highest existing generation (an old file)
        -1 means  use  a  generation  one  higher  than  the  existing
        generation ( a new file)
        -2 means use the lowest existing generation.
        Recognition may be used on the file name.

Examples:

        .ASKF [0] INP Enter name of input data file

        displays

* Enter name of input data file [F]:

on the controlling terminal.  The symbol INP is defined  according  to
the  answer  given.   A  question  mark can be typed for help, and the
message  "file  name"  is  given.   The  default  generation  will  be
overridden if the user explicitly enters a generation number.

        You may  specify  a  default  filename,  filetype,  directory,
device  and  account  to  be  used  for  .ASKF.   These defaults, once
specified, are used for all .ASKF directives until they are removed by
using   .PURGE  to  remove  the  associated  default  variables.   The
following variables (of type  string)  are  set  up  if  defaults  are
desired.   They  are all independant - you only need to set them up if
you want a default for specific field (ie you can have a default  type
without a default name).

o       <DEFACC>        Default account

o       <DEFNAM>        Default name

o       <DEFDIR>        Default directory

o       <DEFDEV>        Default device

o       <DEFTYP>        Default extension (or file type)




5.7  Call Up Another IND File                                   .CALL


        The .CALL directive tells IND to suspend the current file, and
take  commands from another file.  It is as if all of that second file
were inserted at the  place  the  .CALL  directive  exists,  with  the
difference  that  one  file  is not allowed to reference labels in the
other.  All symbols defined by one file are accesible  to  the  other,
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however.  .CALL directives can be nested upto 4 deep.  Format:

        .CALL filename

Default file type is as for IND command, ie .CMD.  Usually the default
device is DSK:  (which is usually your own directory.) However, if IND
was originally invoked with a command like IND TRIM, and  TRIM.CMD  is
not  found  on  DSK:,  it  then  searches  SYS:   for  the  file.   If
SYS:TRIM.CMD existed, then any .CALL directives which it  issues  will
use SYS:  as their default device.




5.8  Close Secondary File                                        .CLOSE


        The .CLOSE directive closes the secondary  file  opened  in  a
.OPEN directive.  It is a noop if no file has been opened (ie no error
occurs if a file is not currently open.)




5.9  Close Secondary Input File                                  .CLOSEI


        The .CLOSEI directive closes the secondary file  opened  in  a
.OPENI  directive.   It  is  a  noop if no file has been opened (ie no
error occurs if a file is not currently open.)




5.10  Get ASCII Code Of A Character                                    .CODE


        The .CODE directive returns  the  ASCII  value  of  the  first
character of a string expression to a numeric variable.  Format:
        .CODE number string-expression

The variable number receives the ASCII code of the first character  in
the string expression.  Examples:

.CODE start "This is a string of characters" .CODE n command

        In the first example, variable start gets the ASCII  code  for
uppercase  T,  while  in the second, command is assumed to be a string
variable, and the code for its first character is returned to  n.   If
command is a null string, n is set to 0.
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5.11  Output Data To Secondary File                                   .DATA


        The .DATA directive specfies text to be output to a  secondary
file opened by a previous .OPEN directive.  An error occurs if no file
is open.  Format:
        .DATA arbitrary text which is not interpreted

        Leading blanks and tabs are stripped from the data, and symbol
substitution is still performed if enabled.

Example:

        .SETS SEND "This is data"
        .OPEN TEMP.DAT
        .DATA 'SEND'

        These directives output "This is data" to the secondary file.



5.12  Convert Date String To Smithsonian Day Number                 .DAYTON


        The .DAYTON directive converts a string expression,  which  is
assumed  to be a date, into a Smithsonian day number.  Smithsonian day
numbers are an easier method for programs to handle  dates  with  than
date  strings  (ie  it  is easier to do things like find out the year,
find out how far apart two dates are, etc.) Format:

        .DAYTON String-expression Numeric-symbol

Example:
        .DAYTON "24-Dec-84" XMASEVE

This stores the date of Christmas Eve 1984 in XMASEVE.   Day  zero  is
17th  November  1858.   Negative day numbers are not allowed.  .DAYTON
accepts dates in any reasonable format, such as  24th  December  1984,
24/12/84, 24 dec 1984, etc.  It cannot accept the names of days of the
week, nor can it accept numeric dates  delimited  by  periods.   If  a
wholly numeric date is entered (as 24/12/84 or even 241284), it adopts
the british convention of assuming the second  number  is  the  month,
rather  the  American  convention  of assuming the first number is the
month.




5.13  Debug IND                                                  .DDT


        The .DDT directive merges SYS:UDDT with the  IND  program  and
then executes an unsolicited breakpoint into DDT.  It is used only for
debugging IND.  When you  have  set  your  breakpoints,  or  otherwise
fiddled, use $P to continue IND execution.
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     This directive accepts no arguments.




5.14  Decrement Numeric Symbol                                          .DEC


        The .DEC directive subtracts one from the value of  a  numeric
symbol.  Format:

        .DEC ssssss

                        where ssssss is a numeric symbol name.



5.15  Delay Execution For A Specified Period Of Time                     .DELAY


        The .DELAY  directive  delays  processing  for  the  specified
number of seconds.  Format:
                        .DELAY numexp

        where numexp is a numeric expression equal to  the  number  of
seconds  to  wait for.  IND just does nothing for the specified period
of time.



5.16  Change Delimiting Character For Substitution                .DELIM


        The .DELIM directive changes the character which  is  used  to
mark  out  variables  for  substitution  in  the  command  file.  This
character is usually ' (apostrophe).  .DELIM can be used to change  it
to any ASCII printing character.  Format:

        .DELIM string-expression

Eg, the directive
        .DELIM ""
means that wherever IND  finds  a  variable  name  surrounded  by  the
ampersand  ()  in  a  command  file,  the  value  of  that variable is
substituted in.




5.17  Disable Option Or Mode                                      .DISABLE


        The .DISABLE directive turns off a specified mode or option of
IND.   See  the  .ENABLE  directive  for  information  about  options.
Format:
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        .DISABLE SUBSTITUTION



5.18  Enable Option Or Mode                                      .ENABLE


                The ENABLE directive is used  to  invoke  one  of  the
special  operating modes or options of IND.  Some modes or options are
ENABLEd by default - you do not need to turn these on, but may wish to
turn  them  off via .DISABLE.  The default settings are listed below ;
they are explained later.  The format of the directives is as below:

        .ENABLE keyword
        .DISABLE keyword

where keyword is from the following list (defaults at  startup  follow
each keyword):

        ABORT - enabled
        COMAND-CMD - enabled
        CONTROL-Z-EXITS - enabled
        DATA - disabled
        EXTENDED-EXEC - disabled
        ESCAPE - disabled
        LEADING - enabled
        LOGGING - disabled
        LOGOUT - disabled
        TRACE - disabled
        SUBSTITUTION - Enabled
        QUIET - Disabled

Keywords, unlike IND directives, may  be  abbreviated  to  any  unique
substring.  It is recommended that you use at least four characters in
your abbreviation - other directives may otherwise make it  non-unique
in a later release of IND.

        When COMAND-CMD is enabled,  the  EXEC  that  IND  passes  its
commands  to is allowed to read the COMAND.CMD file as usual before it
starts.  This is the normal mode.  If you wish to suppress  this,  you
can disable this feature.  The .DISABLE command for this must be given
before any EXEC commands appear in your command file.

        When DATA mode is enabled, IND stops treating the contents  of
the  file  as  commands,  and  instead sends everything it sees to the
secondary data file until a  .DISABLE  DATA  directive  is  processed.
This  is  the  only directive that will be recognised - all others are
treated as data.  DATA mode is useful if you have a number of lines to
send  to  the  secondary  file  (it  saves  a  lot  of individual DATA
directives), or if you wish to send lines with leading blanks or  tabs
to  the  secondary  file.   This mode does not strip these characters.
Substitution is still performed if applicable.

        When EXTENDED-EXEC mode is enabled, IND  uses  an  alternative
form  of  the  EXEC to process your TOPS-20 commands.  This is usually
SYS:MEXEC.EXE, but may be optionally selected to be any other EXEC  by
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recompiling  IND.  The .ENABLE EXTENDED-EXEC command, if used, must be
given before any TOPS20 commands have been issued by the command file.
Once enabled, it cannot be disabled.

        When ESCAPE mode is enabled, any escape characters  that  your
file  transmits  to  the  screen,  via  comments for instance, will be
transmitted as escapes instead of being translated into dollar  signs,
which is what TOPS20 normally does.

        When CONTROL-Z-EXITS are enabled, you can  use  CTRL/Z  as  an
answer to any question from IND, and it will exit immediately, closing
data files first.  When this mode is disabled, IND will not allow  the
user to bypass a question in this manner.

        In substitution mode, the processor substitutes  a  string  in
place   of  a  symbol  name  when  the  symbol  name  is  enclosed  in
apostrophes.  When substitution is operating, it is  performed  before
any  other action is taken with a line, ie before the decision is made
as to whether the line is an IND directive, a  TOPS20  command,  or  a
comment.   (While  obeying  GOTO directives which cause forward motion
through the file, however, substitution is  not  performed  until  the
target  label  has  been  found, to prevent any spurious errors due to
symbols having unexpected values.  This means that, in general, labels
should  not  be  inserted  via substitution, as they may not always be
found.) When substitution is  disabled,  apostrophes  are  treated  no
differently from other characters.

        In TRACE mode, IND prints all commands at the  terminal  after
substitution has been performed on them, but before they are executed.
This gives you a chance to debug complex command  files,  as  the  IND
directives  are  not  usually displayed on the screen, only the TOPS20
commands and comments.

        In QUIET mode, TOPS20 commands which are normally  printed  at
the  terminal as they are executed are instead inhibited from echoing.
Thus the only output appearing on the  screen  is  that  generated  by
questions or comments, or as output from a program.

        When LOGGING is enabled, all characters  that  appear  on  the
terminal  are  also  written to the currently selected logfile, in the
same way that PHOTO or similar programs would do.  This mode cannot be
enabled  if a previous .LOGFILE command has not been given to select a
logfile.  Logging can be selectively enabled and disabled  during  the
course  of  the  command  file, with the logfile remaining open.  This
allows you to record only those sections of  the  dialogue  which  you
feel are important.

        When LOGOUT is enabled, the lower fork is allowed  to  execute
the  LOGOUT or BYE commands, or generally to issue a LGOUT JSYS.  This
is not normally the case, as it can cause IND to end prematurely.  You
can  enable this mode if you wish to be able to use the LOGOUT command
from within a command file.  Make sure that you have closed  all  open
files first.

        When LEADING is enabled, you can use leading blanks before the
"."  that comes before an IND directive.  When it is disabled, the "."
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DIRECTIVES


at the beginning of an IND directive must be at the left hand margin.


     When ABORT is enabled, you can abort an IND command file  at  any
time  by  typing the abort character (usually control-A).  This can be
disabled during sensitive actions with the .DISABLE  ABORT  directive,
but  you  should  be  warned  that  the command file will then be very
difficult to stop should it contain bugs.




5.19  Display A Text String                                     .DISPLAY


        The .DISPLAY directive sends  a  text  string  to  the  screen
verbatim,  without  translation  of control characters and without any
leading or trailing carriage returns or linefeeds.  Format:

        .DISPLAY string-expression

This directive is mainly only useful for sending escape  sequences  to
screen  terminals,  and  is  of  very  limited  use.   To  send normal
messages, use the comment feature of placing your messages on  a  line
after a semicolon.  Example:

        .DISPLAY "$[H"

This sends the sequence to a VT100 to home the cursor.




5.20  Close A Logfile                                        .ENDLOG


        The .ENDLOG directive closes the terminal logfile opened  with
a .LOGFILE directive and releases the asssociated pseudo terminal back
to the pool of system resources.  Format:

        .ENDLOG




5.21  Exit Quietly From An IND File                                .EXIT


        The .EXIT directive terminates IND  execution,  and  does  not
print  any message.  Normally, the message @ <EOF> is displayed on the
screen when a command file is finshed.  Placing the .EXIT directive at
the end stops this.  Also, .EXIT will still exit if placed in a nested
command file.  Use .STOP if you merely wish to terminate  the  current
command file (ie return to the next higher level.) Format:

        .EXIT
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5.22  Define A File Symbol                                 .FILE


        The .FILE directive declares a list  of  symbols  to  be  file
symbols,  and initializes them all to point to NUL:.  The symbols must
not already be defined.  Format:

        .FILE symbol,symbol,symbol....

The list of symbols can contain from 1 to 10 symbol names.




5.23  Call A Subroutine                                       .GOSUB


        The  .GOSUB  directive  saves  the  current  position  in  the
indirect  file  and then branches to a label.  The label specifies the
start of a subroutine which is terminated by a .RETURN directive.  The
maximum nesting depth for subroutine calls is 10.  Format:

        .GOSUB  label

where label is the tag at the start of  the  subroutine,  without  the
leading dot or trailing colon.




5.24  Branch To A Label                                             .GOTO


        The .GOTO directive causes a branch from one line in a command
file  to  another.   All commands between the GOTO and the destination
are ignored.  Btanches may go forwards or backwards in the  file,  but
not  to  labels  in  a  different command file (eg not to the one that
.CALLed this one.) Format:

        .GOTO label




5.25  Logical Test                                                      .IF


        A number of directives make various sorts  of  logical  tests,
that is, those whose results are either true or false.  If the test is
true, IND processes the remainder of the line as another command.
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5.25.1  Test If Symbol Meets Specified Condition                        .IF - 

        The .IF directive compares a numeric or string symbol with  an
expression  of  the  same type to determine if one of several possible
conditions is true.  If the condition is satisfied, IND  executes  the
remainder  of  the  command  line.   Numeric  tests are made purely on
magnitude ;  string tests are made by comparing the strings  character
by  character:   when the strings differ, it is the order of the first
differing  characters  that  determine  which   string   is   greater.
Upper/lower  case  is  ignored  when  making  this comparison.  If one
string is a substring of another (eg LOCK  and  LOCKED),  the  shorter
string is considered the lesser of the two.
        Thus, "APPLE"  is  equal  to  "apple",  "pear"  is  less  than
"TOMATO", and "under" is less than "underfoot".
        Format:

        .IF symbol relop expression command

where:  symbol= 1-9 character name of numeric, real or string symbol
        relop = one of the following relational operators:

                EQ or =         :  equal to
                NE or ~= or <> or >< :  Not equal to
                GE or >= or =>  :  Greater than or equal to
                LE or =< or <=  :  Less than or equal to
                GT or >         :  Greater than
                LT or <         :  Less than

        expression = expression of same type as symbol (except that  a
        real  expression  can  be converted to integer, and integer to
        real without any problem.)

Examples:

        .SETS X "A"
        .SETS Y "BBC"
        .IF X LT Y .GOTO START

        The value of string X is less than that of Y,  so  a  transfer
will occur to the line labelled .START:  .

        .IF N1 < 200*PAY SYSTAT ALL NO OPERATOR

        If the value of numeric symbol N1 is less than  the  value  of
symbol  PAY  multiplied  by  200,  then  the  SYSTAT  command  will be
executed.




5.25.2  Test If Symbol Is Defined Or Not Defined                 .IFDF/.IFNDF - 

        These directives test whether or not a symbol is  defined  yet
to  IND.   If  the test is true, the rest of the command is processed.
The value is not tested.  Formats:
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        .IFDF symbol command
        .IFNDF symbol command

        where symbol is the symbol name.  Examples:

        .IFDF a .GOTO 100
        .IFNDF tim .ASK tim Do you want to set the time?



5.25.3  Test If Logical Symbol Is True Or False                     .IFT/.IFF - 

        The .IFT/.IFF directives test if a logical symbol is  true  or
false.   If  the  test is true, the remainder of the line is executed.
Format:

        .IFT symbol command
        .IFF symbol command

Examples:  .IFT Wheel ^equit

        This executes the ^e quit command if the logical symbol  wheel
        is true.



5.26  Increment A Numeric Symbol                                        .INC


        The  .INC  directive  increments  a  numeric  symbol  by  one.
        Format:

        .INC symbol

        One is added to the value of  symbol,  which  must  previously
have been defined as numeric.




5.27  Open Terminal Logfile                                    .LOGFILE


        The .LOGFILE directive declares a file to be  used  to  record
all characters displayed at the terminal.  Although it opens the file,
characters are not  logged  until  an  .ENABLE  LOGGING  directive  is
issued.  Format:

        .LOGFILE filename

Filename must be a valid file to which you have write access.  A spare
pseudo terminal must exist for this function to be effective.
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5.28  Declare Logical Symbols                                   .LOGICAL


        This directive declares a  list  of  symbols  to  be  of  type
logical,  and  initializes  them  to  false.  They must not already be
defined.  Format:

        .LOGICAL symbol,symbol...




5.29  Make A String Lower Case                                  .LOWER


        The .LOWER directive forces all  alphabetic  characters  in  a
string to be upper case.  (See .RAISE for the converse.) Format:

        .LOWER Symbolname

where SYMBOLNAME is the  name  of  an  existing  string  symbol.   All
alphabetic  characters  in  that string will be made lowercase.  Other
characters are not affected.




5.30  Convert Day Number To Date String                            .NTODAY


        The .NTODAY directive converts a Smithsonian day number into a
date string.  Format:

        .NTODAY numeric-expression string-variable

The date is converted in the format dd-mmm-yy, unless  it  was  before
1900, in which case it is in the format dd-mmm-18yy.  Example:

        .DAYTON <DATE> Today .NTODAY Today+7 Nextweek

        This results in string symbol  Nextweek  containing  the  date
        representation  of  one week after today, no matter whether it
        is a different month or year.




5.31  Declare Numeric Symbols                                   .NUMERIC


        This directive declares a  list  of  symbols  to  be  of  type
numeric,  and  initializes  them  to  zero.   They must not already be
defined.  Format:

        .NUMERIC symbol,symbol...
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5.32  Open Secondary File                                             .OPEN


        The .OPEN directive opens the  specified  secondary  file  for
output.  Format:

        .OPEN filename.typ.gen

A usual TOPS20 filespec can be entered, with any optional  fields  (eg
;ACCOUNT, ;BLOCKSIZE.) There is no default type.



5.33  Open Secondary File For Append                                   .OPENA


        This directive is identical to .OPEN, except that the file  is
opened for append access only.



5.34  Open File For Input                                     .OPENI


        The .OPENI directive opens a file for reading with  the  .READ
directive.   The  file  must exist.  There is no default name or type.
Format:

        .OPENI filename

The file must be ASCII (ie simple text)  and  the  records  cannot  be
longer than the maximum length of a string variable.




5.35  Pad A String With Blanks To A Specified Length                    .PAD


        The .PAD directive takes a specified string and pads it  to  a
particular  length  using  spaces.   This can be useful for formatting
printouts using string substitution.  Format is:

        .PAD string numeric-expression

The string variable is padded to the length specified by  the  numeric
expression.   A  warning  is generated if the string is already longer
than the length you want to pad it to.
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DIRECTIVES


5.36  Break A String Into Substrings                                   .PARSE


        The .PARSE directive is a very powerful mechanism for breaking
up  command  strings, or data from files.  The function it performs is
to take a string of characters and chop it up into  smaller  parts  by
looking  for  specific characters which delimit portions of the input.
You supply the string to be chopped (referred to as the parse  string)
and  another string which contains a set of delimiter characters which
are searched for one by one in  the  parse  string.   This  string  of
delimiters  is  referred to as the control string.  A set of variables
is supplied which receive the chopped out portions.  The command looks
like:

.PARSE parse-string control-string Out1 out2 out3 ...

The trailing dots indicate that you can have as many output strings as
you want.  What happens is this:

        A search is made in the parse string for the  first  character
in  the  control  string.   When it is found, the portion of the parse
string up to that point is copied into variable  out1  (not  including
the  terminating  character).   The search is then continued from that
point in the parse string for the  next  character  from  the  control
string expression.  This substring, when found, is copied to out2, and
so on.  If we run out of characters in the control string while  there
is still more to chop up, we use the last character repeatedly.  If we
run out of parse string before  all  the  variables  have  had  values
assigned  the  remaining variables contain null strings.  The variable
<STRLEN> contains the actual number of subtrings found.  If we run out
of  output  variables,  the  last  output  variable contains the whole
remainder of the string up to the point currently parsed.  Examples:

        .SETS address "12,Morrow lane,Datchworth,Herts."
        .PARSE address "," number road town county

This breaks the variable address up into "12" which is put in variable
number,  "Morrow  lane"  which is put into road, "Datchworth" which is
put into variable town, and "Herts." which is put into county.  If the
control string had been ", ," instead, we could have split up "Morrow"
from "lane" as well.




5.37  Pause For Operator Action                                      .PAUSE


        The  .PAUSE  directive  causes  IND  to  temporarily   suspend
processing  its  command  file, and allow the operator to enter TOPS20
commands from the keyboard.  It acts rather like a PUSH command in  an
ordinary  TAKE  file.   When  the  .PAUSE  directive  is  reached, IND
displays the following message at the user's terminal:

[IND - pausing.  To continue type 'POP'.]
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        Any commands may be entered (except LOGOUT or  BYE)  and  when
the user wishes to continue they can type POP.  The message

[IND - continuing.]

is then displayed at  the  terminal.   Both  the  above  messages  are
suppressed if the .ENABLE QUIET directive has been issued.




5.38  Set Input File To Specified Position                      .POSITION


        The .POSITION directive is only valid if an input file (opened
with  .OPENI)  is  currently open.  It takes as its argument a numeric
expression, which is the byte number to set the file  pointer  to  (ie
the next byte or character read will be that one.) You can use this to
re-read parts of an  input  file  if  you  have  previously  read  the
position using the <BYTEPOS> system symbol.  Format:

        .POSITION numeric-expression

A fatal error occurs if the expression is non-positive, or if no input
file is open.




5.39  Remove A Symbol And Its Definition                         .PURGE


        The .PURGE directive removes a  list  of  variables  from  IND
entirely.   Their  values  and  types  are totally forgotten.  This is
mainly of use when you have set up a special symbol such  as  <STRDEF>
for  a  default  for  one  question,  and  you  then  want the default
forgotten.  Format:

        .PURGE var1,var2,var3,....
The list may be as long as you wish.




5.40  Change Current Radix For Integers                          .RADIX


        The .RADIX diretive changes the current base or radix used for
typing  out  numeric  symbols,  reading  them  from  the terminal, and
reading them in expressions in command files.  Format:

        .RADIX numeric expression.

The numeric expression involved is ALWAYS interpreted as being in base
10.   If  only  output  is to be performed with a different radix, the
radix may be anything from 2 to 36.  If input is to be performed also,
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DIRECTIVES


it can only be between 2 and 10.  Example:

.SETN OLDRADIX 10               ;Save old radix
.RADIX 5                        ;Do some WEIRD stuff in rad 5
.
.
.RADIX OLDRADIX         ;Set the radix back again





5.41  Raise A String To Upper Case                                  .RAISE


        the .RAISE directive forces all the  characters  in  a  string
variable to be upper case.  Format:

        .RAISE string-variable-name

Non-alphabetic  characters  are  unaffected.   The  .LOWER   directive
performs the converse operation.




5.42  Read A Record From Input File                               .READ


        The .READ directive reads a line from the currently open input
file  (set  with .OPENI) and places its contents in a string variable.
Format:

        .READ ssssss

Where sssss is the name of a string variable.  If end of file has been
reached,  the variable is set to the null string and the system symbol
<EOF> becomes true.




5.43  Define A Floating Point Symbol                             .REAL


        This directive defines a list of symbols to be floating  point
and  initializes  them  to  zero.  It is not necessary to declare your
variables in this way, but it can be helpful.  Format:

        .REAL symbol,symbol,...

Example:

        .REAL loadav,cycletime
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DIRECTIVES


        5.44  Return From A Subroutine                                       .RETURN


        The .RETURN directive is used  at  the  end  of  a  subroutine
        called by a
.GOSUB directive, and transfers control  to  the  line  following  the
.GOSUB that
called it.  Format:

        .RETURN




5.45  Reset Input Data File                               .REWIND


        The .REWIND directive "rewinds" the input file, ie  it  causes
the  next read from the file opened with .OPENI to come from the start
of the file.  Format:

        .REWIND




5.46  Run A Program Requiring Terminal Input                        .RUN


        The .RUN directive runs a program under the control of IND  in
much  the same way as the EXEC RUN command does.  However, whereas the
Run command to the EXEC, when in an  IND  file,  would  cause  program
input  to  come  from  the command file, the .RUN directive allows the
user to interact with the program via the terminal.  When the  program
exits,  IND continues to process the command file.  This can be useful
if you want to invoke an editor, say, from within an  IND  file.   You
can  run the editor in the normal way - however, you must then put the
editor commands within your command file.  Format:

        .RUN program optional-data

        The filetype of the program is presumed to be .EXE, and may be
omitted.   The  directory  name  is  presumed  to be DSK:, and must be
entered explicitly if different.  This command loads the rescan buffer
in the same way that the EXEC does, so a command such as:

        .RUN sys:rev *.dat

        is permissible, and causes the rescan buffer to be loaded with
REV *.DAT, thus causing REV to start automatically reviewing all files
of type DAT.  This may be applied to any program that  normally  reads
the rescan buffer that the EXEC supplies (eg TV,SYSDPY,RUNOFF.)
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DIRECTIVES


5.47  Set Symbol To True Or False                                .SETT/.SETF


        The .SETT/.SETF directives define or change  the  value  of  a
logical  symbol.   The symbol must be undefined, or previously defined
as logical.  Formats:

        .SETT symbol
        .SETF symbol

        The .SETT directive sets the symbol to true, the  .SETF  makes
        it false.



5.48  Set Symbol To File Value                                      .SETFI


        The .SETFI directive sets the  value  of  a  file  symbol,  ie
associates a symbol with a filename (either an existing filename, or a
new filename.) Format:

        .SETFI symbol filename.

        Filename can  be  in  standard  TOPS20  format,  symbol  is  a
standard symbol name.



5.49  Set Symbol To Numeric Value                                      .SETN


        The .SETN directive sets the value of a numeric symbol  to  be
equivalent  to  the  value  of a given numeric expression.  The symbol
must be previously numeric, or undefined.  Format:

        .SETN symbol expression

where symbol is a valid symbol name, and  expression  is  any  numeric
expression.  Examples:

        .SETN number 103
        .SETN number2 3*(a2-2)



5.50  Set Symbol To Floating Value                                      .SETR


        The .SETR directive sets the value of a floating point  symbol
to  be equivalent to the value of a given expression.  The symbol must
be previously real, or undefined.  Format:

        .SETR symbol expression

where symbol is a valid symbol name, and  expression  is  any  numeric
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DIRECTIVES


expression.  Examples:

        .SETR number 103.45
        .SETR number2 3*(a2-2.506)



5.51  Set Symbol To String Value                                       .SETS


        The .SETS directive associates a string with a string  symbol.
        Format:

        .SETS symbol strexp

where symbol is  a  string  symbol,  and  strexp  is  a  valid  string
expression.  Examples:

        .SETS x "hello there"
        .SETS type a[1:6]+"."+b[1:3]

        The first directive assigns the string hello there to symbol x
;   the  seconds directive makes string symbol type have a value equal
to the first siz characters of the value of symbol a, followed by a .,
followed by the first 3 characters of symbol b.



5.52  Terminate Current Command File                                   .STOP


        The .STOP directive closes any currently open IND  data  file,
and terminates the command file.  If the current command file has been
called from a higher level one, the current file only  is  terminated,
and control is returned to the upper file.  The message

@ <EOF>

is displayed only if this is the top-level command file.



5.53  Declare String Symbol                             .STRING


        The .STRING directive declares a list of symbols to be of type
string  and  sets  their  values to be the null string.  They must not
already be defined.  It is not necessary to declare variables in  this
manner.  Format:

        .STRING ssss,sssss,sssss...

where the ssss are symbols names to be declared.
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DIRECTIVES


5.54  Pass A Command To An Interactive Program                         .TELL


        In certain rare circumstances it is desired to  use  the  .RUN
directive  to  run a program, allowing the user to type his or her own
commands at it, but first to give the program one or two  initializing
commands.   The  .TELL directive allows this.  Only one command can be
passed, however.  Format:

        .TELL String-expression

Examples:

        .TELL "TRANSFER=INIT.PST$" .RUN SYS:PSTAT.EXE
        Will run PSTAT, but  tell  it  to  transfer  to  the  file  of
        commands  INIT.PST  before  accepting input from the terminal.
        INIT.PST  presumable   contains   some   environment   setting
        commands.




        5.55  Test String Symbol                                         .TEST


        The .TEST directive allows you to determine the  length  of  a
string  symbol.   After  it is executed, the system symbol <STRLEN> is
set to  the  length  of  the  tested  string.   The  symbols  <ALPHA>,
<ALPHANUM>  and  <NUMERIC> are also set to indicate whether the string
was alphabetic, alphanumeric or numeric only.  Format:

        .TEST symbol

where symbol is a string symbol to be tested.  Example:

        .SETS a "1234"
        .TEST a

Symbol <STRLEN> would now equal 4.



5.56  Test If A File Exists                                       .TESTFILE


        The .TESTFILE directive takes as its argument a filename,  and
sets the special symbol <FILESTAT> to indicate whether or not the file
exists.  Format:

        .TESTFILE filename

        The symbol <FILESTAT> is set as follows:

        1       File exists normally
        0       File does not exist
        -1      File exists, but is deleted.
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DIRECTIVES


        -2      File exists, but is invisible.
        -3      File exists, but is offline.
        -4      Filespec is invalid (ie no such directory or  no  such
        device)

        If a file is deleted  and  invisible,  it  will  be  shown  as
invisible.   If  a  file is offline and invisible, it will be shown as
offline.

     The symbols <FILDEV>,  <FILNAM>,  <FILDIR>,  <FILTYP>,  <FILGEN>,
<FILPRO>,  <FILACT>, <FILCRE>, <FILRED> are also set up to contain the
various       parts       of       the        filespec        (device,
directory,name,type,generation,protection,account,creation  date/time,
read date/time.) These fields are always set up, whether or  not  they
were  specified  in  the  filespec.  They are all string symbols.  The
symbols <FILPAG>,<FILSIZ> and <FILBYS>  are  set  up  to  contain  the
number  of  pages in the file, the number of bytes, and the byte size.
They are all numeric symbols.  They can only be set up  if  <FILESTAT>
is 1,-1 or -2 (i.e.  if the file is online.)



5.57  Trim Trailing Blanks And Tabs                                  .TRIM


                The .TRIM directive removes trailing blanks  and  tabs
from an input string.  Format:
        .TRIM variable

        The variable has all trailing blanks and tabs remove from  it.
It must already be defined of type string.



6.0  IND ERROR MESSAGES AND WARNINGS

6.1  Informational Messages

        These messages require no action on your  part.   They  merely
inform you about some action being taken by IND.

[IND - exiting]
                                        This message is issued after a
                        fatal  error  message  to  indicate  that  IND
                        cannot continue to execute your command file.

[IND - pausing.  To continue type "POP"]
                                        This is typed on the  terminal
                        whenever  a .PAUSE directive is encountered in
                        the  command  file.   It  tells  you  how   to
                        terminate  the  .PAUSE directvive and continue
                        with command file execution.

[IND - continuing]
                                        This is typed after  you  have
                        typed   POP   to   continue   after  a  .PAUSE
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IND ERROR MESSAGES AND WARNINGS


                        directive.




6.2  Warning Messages

        These messages indicate some condition that, while it does not
prevent  the command file from continuing to be executed, may indicate
some problem with your command file that you ought  to  be  aware  of.
The action you take depends on how serious you consider the problem to
be.
%IND - can't DELAY for a negative amount of time
                                        The     numeric     expression
                        supplied  to  a  .DELAY  directive  yielded  a
                        negative  value.   You  cannot  delay  for   a
                        negative amount of time.

%IND - logfile already open
                                You  have  given  a  second   .LOGFILE
                        command  when the previous logfile was already
                        open.  The second command is ignored, and  the
                        logfile stays open.

%IND - no PTYs available for logging - releasing logfile.
                                IND could not assign a pseudo-terminal
                        for  use  in  creating  a  logfile.   Thus, no
                        logfile can be created.

%IND - string is already longer than .PAD length:
                                You  tried  to  pad  a  string  to   a
                        particular length with the .PAD directive, but
                        the string was already longer than  this.   It
                        has not been modified.




6.3  Fatal Error Messages.

        These messages indicate an error condition in IND  that  means
that  it  cannot safely continue.  (There are some exceptions, see the
individual descriptions.) They are all followed  by  printing  of  the
command  line  that  has  caused  the  error, and in some cases by the
particular portion of that command that is in question.
?IND - ambiguous:
                                        The  keyword  specified  in  a
                        .ENABLE  or  .DISABLE  directive is ambiguous,
                        that is it is an abbreviation of more than one
                        valid keyword.

?IND - answer not in range
                                        This is  not  a  fatal  error.
                        The  response given to a .ASKN directive which
                        had specified valid ranges for the answer, did
                        not  fall  within  the  ranges  allowed in the
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IND ERROR MESSAGES AND WARNINGS


                        command file.  The question is repeated  until
                        the answer is valid.  Note that this condition
                        can occur if you have  specified  both  ranges
                        and  a  default  value,  but the default value
                        does not lie within the range,  and  the  user
                        attempts to take the default.

?IND - bad numeric constant:
                                        IND expected to see a  numeric
                        constant   at   some   point   in   a  numeric
                        expression, as what was there was not an  open
                        bracket  or  a  numeric symbol.  The constant,
                        however, could not be evaluated.

?IND - bad numeric range
                                        A numeric expression  as  part
                        of  a  substring range or a .ASKx range is not
                        correctly structured.

?IND - bad range format:
                                        This    indicates    incorrect
                        formatting  of a substring range, or the range
                        arguments to a  directive  such  as  .ASKS  or
                        .ASKN.   IND  has  parsed one of the ranges or
                        default values and expects to see either a ":"
                        to  indicate  another value or "]" to indicate
                        no more ranges.  Neither of these was found.

?IND - blank symbol name in declaration list:
                                A comma without a following  name,  or
                        some  other  syntactic  error, is present in a
                        declaration   list   following   a   .NUMERIC,
                        .LOGICAL, .STRING or .FILE directive.

?IND - blank symbol name for .PURGE:
                                A  .PURGE  directive  has  detected  a
                        missing   name   or  an  extra  comma  in  its
                        declaration list.  This should be of the  form
                        .PURGE var1,var2,var3...
                        Blanks are permitted between the names and the
                        commas.

?IND - can't .CALL file:
                                        The file specified in a  .CALL
                        directive  cannot be found, or the filespec is
                        invalid.   A  detailed  JSYS   error   message
                        follows.

?IND - can't .ENABLE DATA without data file open.
                                        An .ENABLE DATA directive  was
                        issued  without  a data file having previously
                        being opened via an .OPEN or .OPENA directive.

?IND - can't get get handle on logfile:
                                        IND cannot get a JFN  for  the
                        file  specified  in the .LOGFILE directive.  A
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IND ERROR MESSAGES AND WARNINGS


                        JSYS error message follows.  The  filespec  is
                        probaly  incorrect,  or you do not have access
                        to the directory.

?IND - can't OPEN file:
                                        The file referenced in a .OPEN
                        or .OPENA directive cannot be opened for write
                        or append access.  The JSYS error is given  on
                        the following line.

?IND - can't OPEN input file:
                                IND cannot open the file specified  in
                        the  .OPENI  directive,  even  though the file
                        exists.  This is a rare error.  A  JSYS  error
                        message follows.

?IND - can't RUN program:
                                        The  program  specified  in  a
                        .RUN  directive could not be found, started or
                        mapped for some reason.  This message will  be
                        followed  by  a  specific  JSYS  error message
                        explaining why the program could not be  found
                        or  run.   Common errors include specifying an
                        incorrect name for the program  (e.g  omitting
                        to specify SYS:  for TV.)

?IND - can't open command file:
                                        The file specified in a  .CALL
                        directive has been found, but cannot be opened
                        for  read  access.   A  JSYS   error   message
                        follows.

?IND - can't open logfile:
                                        IND cannot  open  the  logfile
                        specified  in  the .LOGFILE directive.  A JSYS
                        error message follows.

?IND - can't understand number:
                                        The     numeric     expression
                        specified  as  the  second argument in a .SETN
                        expresson was invalid for some  reason.   This
                        message  will usually be preceded by some more
                        informative   message   about   the    problem
                        encountered in the numeric expression.

?IND - can't understand string comparison:  Internal error
                                        This is a fatal internal error
                        which should not occur.  It should be reported
                        to your system programmers, and  will  be  the
                        result of some catastrophe in a .IF directive.

?IND - cannot initialize fields for parse:
                        Some error occurred trying to  set  all  field
                        variables in a .PARSE directive to null before
                        attempting the parse.  Some other  error  will
                        probably  already have been printed indicating
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IND ERROR MESSAGES AND WARNINGS


                        the problem.  This may be an error in IND,  or
                        you may have too many strings defined.

?IND - Control string is null:
                                The  control  string  expression  (the
                        second  thing in a .PARSE directive) evaluated
                        to a null string.  IND cannot break the  parse
                        string into subfields in this case.

?IND - End of file while searching for label "
                                        While attempting to satisfy  a
                        .GOTO directive which referenced a label which
                        ahd not yet been found, the end  of  file  was
                        reached.    The  label,  therefore,  does  not
                        exist, and the .GOTO directive  is  in  error.
                        The  target  label name is printed out as part
                        of the error message.

?IND - error executing command:
                                        Some error occured while using
                        CRCMD  to  execute  an  EXEC command.  This is
                        usually some error indicating  that  the  EXEC
                        cannot   be   found,   or   that   there   are
                        insufficient system resources to allocate more
                        forks.   The exact JSYS error message follows.
                        This error may indicate an internal  error  in
                        IND.

?IND - error in filename:
                                        The filename  specified  in  a
                        .SETFI directive is not valid for some reason.
                        A more explanatory JSYS error message follows.

?IND - error writing to data file:
                                        Some  system   error   occured
                        writing  to  the  data  file  as a result of a
                        .DATA directive.  The JSYS  error  follows  on
                        the next line.

?IND - failure to parse command:
                                        A line was seen to start  with
                        a valid IND directive, and an attempt was made
                        to parse the  rest  of  the  directive.   This
                        attempt  failed for some reason.  This message
                        will  always  be   preceded   by   some   more
                        informative  message  from  a part of IND that
                        was trying to cope with the invalid section of
                        your directive.

?IND - fatal internal error in numeric parser  -  impossible  operator
invoked.
                                        This error should  not  occur,
                        It  indicates  an error in IND's numeric parse
                        routines concerning operators.

?IND - File already open:
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IND ERROR MESSAGES AND WARNINGS


                                        An .OPEN  directive  was  used
                        when  another  .OPEN  directive was already in
                        force, ie the  previous  .OPEN  has  not  been
                        followed  by a .CLOSE.  Only one data file may
                        be in use at a time.

?IND - input file already open:
                                        An .OPENI directive  was  used
                        when  another  .OPENI directive was already in
                        force, ie the previous  .OPENI  has  not  been
                        followed  by  a  .CLOSEI.  Only one input file
                        may be in use at a time.

?IND - invalid filespec:
                                        The filespec referenced  in  a
                        .TESTFILE  directive is invalid.  A JSYS error
                        message follows  which  explains  the  problem
                        further.

?IND - input record too long:
                                A record read from an input file  with
                        the   .READ  directive  was  longer  than  the
                        maximum permitted string length.

?IND - invalid system symbol type
                                        An attempt was made to perform
                        substitution using a system symbol not of type
                        string or numeric.

?IND - length to pad string to is too great:
                                The padding length in a .PAD directive
                        must not exceed the maximum length of a string
                        (currently 120 characters).

?IND - logical symbol not defined:
                                        The  symbol  referenced  in  a
                        .IFT  or .IFF directive is not a known logical
                        symbol.

?IND - maximum file nesting depth exceeded
                                        Too    many    nested    .CALL
                        directives  have  been  issued.   The  current
                        maximum is 4.

?IND - mismatched " in string constant:
                                        A string  expression  contains
                        an odd number of quote characters (").

?IND - mismatched quotes while substituting:
                                        An apostrophe has  been  found
                        while  substitution  was  enabled,  and it was
                        assumed that this marked the start of a symbol
                        for value substitution.  No closing apostrophe
                        was found, however.

?IND - no data file open:
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IND ERROR MESSAGES AND WARNINGS


                                        A .DATA  directive  was  given
                        without   a   preceding   .OPEN  directive  to
                        indicate the destination for secondary data.

?IND - no field variables for .PARSE:
                                After the  parse  string  and  control
                        string expression.  IND expects to find a list
                        of variables to receive the individual  fields
                        as  they are parsed in a .PARSE directive.  It
                        could not find any.  Check your syntax.

?IND - no input file open:
                                        A .READ or  .REWIND  directive
                        has  been  given  without  a  matching  .OPENI
                        directive.

?IND - No name for symbol:
                                Some directive that requires a name to
                        define a symbol has been given a blank name.

?IND - non-numeric system symbol in numeric expression:
                                        A system symbol being used  in
                        a numeric expression is not of numeric type.

?IND - numeric answer required
                                        This is  not  a  fatal  error.
                        The  response  given  by  the  user to a .ASKN
                        question was not numeric, or contained invalid
                        data.   The  question  is  repeated  until the
                        answer is valid.

?IND - .RETURN when not in subroutine:
                                        A .RETURN directive  has  been
                        given without a matching .GOSUB.

?IND - string length not in range
                                        This is not a fatal error.   A
                        .ASKS  directive  has  specified  maximum  and
                        minimum permissible  lengths  for  the  user's
                        answer.   The  user  has  supplied  an  answer
                        outside this range.  The question is repeated.

?IND - string space exhausted:  recursive call to SQUEEZE.
                                        There is no more room left for
                        storage of string symbol values, as an attempt
                        has just  been  made  to  collect  all  unused
                        space,  and  this  has  still not freed enough
                        space  to  store  the  new  string  that  this
                        command  wants  to  define.   Ask  your system
                        programmer  to  build  IND  with  more  string
                        storage space.  ?IND - string storage full
                                        This   error    is    somewhat
                        misleading.  It in fact indicates that IND has
                        no room to store the name of a new symbol  (of
                        whatever   type)   that  the  current  command
                        attempts to define.
	IND - Enhanced, programmable command files for TOPS20         Page 46
IND ERROR MESSAGES AND WARNINGS


?IND - symbol to be parsed does not exist:
                                The  first  variable  specified  in  a
                        .PARSE directive should be of type string.  In
                        this case, it does not appear to exist.

?IND - string too long:
                                        A   string   that   is   being
                        assigned to a string symbol contains more than
                        256 characters.  This  is  an  absolute  upper
                        limit on string lengths.

?IND - subroutine nesting depth exceeded:
                                        Too   many   nested    .GOSUBS
                        (currently  more  than  4)  have  been issued.
                        Recode your file to  involve  less  subroutine
                        nesting.

?IND - substring limits invalid:
                                        Limits   specified    for    a
                        substring in a string expression either do not
                        specify  the  correct  number  of  limits,  or
                        specify limits which are outside the bounds of
                        the string.  If limits are specified to  cause
                        substring chopping, there must be two and only
                        two specified, they must both be greater  than
                        1,  the  upper  bound  must be greater than or
                        equal to the lower bound, and both bounds must
                        fall within the string length.

?IND - symbol does not exist for increment/decrement:
                                        The symbol specified in a .IND
                        or .DEC directive is either not defined, or is
                        defined as not numeric.

?IND - symbol is already defined:
                                A  symbol  declared  in  a   .LOGICAL,
                        .NUMERIC,   .FILE   or  .STRING  directive  is
                        already defined.  This is not permitted.

?IND - symbol is invalid type for assignment:
                                        The  symbol  specified  in   a
                        .SETT,  .SETF, .SETN, .SETS or .SETF directive
                        has already been defined  as  a  symbol  of  a
                        different type.

?IND - symbol is not a file symbol:
                                        The symbol  specified  as  the
                        destination  in an .ASKF directive has already
                        been defined with a type other than file.

?IND - symbol is not logical:
                                        The   symbol   specified   for
                        assignment  in  a  .ASK  directive has already
                        been defined with a type other than logical.

?IND - symbol is not numeric or string for comparison:
	IND - Enhanced, programmable command files for TOPS20         Page 47
IND ERROR MESSAGES AND WARNINGS


                                        The symbol  specified  as  the
                        first  operand  in  an  .IF directive is not a
                        numeric or string symbol.  These symbols  must
                        be numeric or string.

?IND - symbol is not numeric:
                                        The   symbol   specified   for
                        assignment  in  a  .ASKN directive has already
                        been defined with a type other than numeric.

?IND - symbol is not string:
                                        The  symbol  specified  in   a
                        .ASKS  or  .READ  directive  has  already been
                        defined with a type other than string.

?IND - symbol table full
                                        There is no room left in IND's
                        internal  tables to define the symbol that the
                        current command is attempting to define.

?IND - Symbol to be .PURGE'd is not defined:
                                Some symbol in your  .PURGE  list  has
                        either never been defined, or has already been
                        purged.

?IND - system symbol in string expression is not of type string:
                                        A system symbol  in  a  string
                        expression  has  been  used, but the symbol is
                        not of type string.

?IND - system symbol type not logical:
                                        A system symbol in a  .IFT  or
                        .IFF   directive   is  not  of  type  logical.
                        Example:  .IFT <STRLEN> .GOTO a .

?IND - table error on parameter startup
                                        This  is   a   serious   error
                        encountered  when parsing parameters in an IND
                        command line.  This error should never occur.

?IND - undefined symbol for substitution:
                                        While  attempting  to  perform
                        substitution   of   a   symbol   enclosed   in
                        apostrophes, a symbol was found which was  not
                        defined.

?IND - unidentifiable command:
                                        A line in a command file began
                        with a dot (".") indicating that it was either
                        an IND directive or a label.   It  was  not  a
                        valid  IND directive and was not followed by a
                        colon, so could not be a  label  either.   IND
                        cannot understand what you are trying to do.

?IND - unknown numeric symbol in expression:
                                        A symbol  name  in  a  numeric
	IND - Enhanced, programmable command files for TOPS20         Page 48
IND ERROR MESSAGES AND WARNINGS


                        expression was not numeric or was not defined.

?IND - unknown relational operator:
                                        The operator  specified  in  a
                        .IF   directive  is  not  a  valid  comparison
                        operator (ie is not EQ, NE ,=, ~=, etc.).

?IND - unknown string symbol in expression:
                                        A  symbol  name  in  a  string
                        expression  is  undefined  or  is  not of type
                        string.

?IND - unknown string symbol in .PAD:
                                The string symbol in a .PAD  directive
                        is not a string symbol.

?IND - Unknown string variable to .TRIM:
                                The variable given to .TRIM is not  of
                        type string, or does not exist.

?IND - Unmatched parentheses:
                                        A numeric expression  in  this
                        command  conrains  more  open brackets than it
                        does close brackets.

?IND - unrecognised .ENABLE/.DISABLE flag:
                                        The  keyword  specified  in  a
                        .ENABLE  or  .DISABLE directive is not a known
                        keyword, or valid abbreviation of one.

?IND - yes or no required
                                        As  a   result   of   a   .ASK
                        directive,  the  processor asked a question of
                        the user at  the  terminal.   A  response  was
                        given  that  was  not YES, NO or return.  This
                        error is not fatal - the  question  is  merely
                        repeated until you give a valid answer.