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MODULE TABLELOOK=
!Search a command table
BEGIN
!
! Conditionals
!
COMPILETIME FTKLUDGE=1;

!
! Table of Contents
!
FORWARD ROUTINE
TABLELOOK,	!Find an entry in a dispatch table
CMD_ENTRY_CHECK;

!
! REQUIRE & LIBRARY Declarations
!
LIBRARY 'MACS';

!
! Version
!
THIS_IS[TABLELOOK]	VERSION [1]	EDIT [3]	DATE[8,MAY,78]

!
! Literals & FIELD defs
!
LITERAL CMD_NOT_FOUND=0,	CMD_AMBIGUOUS=1;

FIELD CMD_FIELDS=
	SET
	CMD_TEXT_ADDR=[0,18,18,0],	!Addr of ASCIZ string to match
	CMD_VALUE=[0,0,18,0]		!Value of command (usually routine addr)
	TES;

!
! Routines
!
GLOBAL ROUTINE TABLELOOK(TBL,STR)=
!Routine to find an entry in TBL for which STR is a unique abbreviation
!Arguments:
!TBL:	A command table (TOPS-20 format)
!STR:	Address of an ASCIZ string
!Returns:
!	Address of entry in table if found uniquely, or
!		0 if entry is not found
!		1 if entry is ambiguous
BEGIN
LOCAL	TPTR,	!Byte pointer to command we are checking
	CMDIMAX;	!Addr of last entry in command table

CMDIMAX=.(.TBL)<18,18>;
%IF FTKLUDGE
	%THEN IF .CMDIMAX EQL 0
		THEN CMDIMAX=..TBL;
	%FI
CMDIMAX=.CMDIMAX+.TBL;

INCR CMDI FROM (.TBL+1) TO .CMDIMAX DO
	BEGIN
	LOCAL	TC,	!Character from table
		SC;	!Character from user's string
	CMD_ENTRY_CHECK(.STR,.CMDI,TC,SC);	!See if there is a match
	IF .SC EQL 0 THEN 	!An abbreviation?
		BEGIN
		IF .TC EQL 0 THEN RETURN .CMDI;	!Win if we read the whole table string
		IF .CMDI EQL .CMDIMAX THEN RETURN .CMDI; !No ambig check off end
		CMD_ENTRY_CHECK(.STR,.CMDI+1,TC,SC);
		IF ((.SC EQL 0) OR (.TC EQL 0)) THEN RETURN CMD_AMBIGUOUS;
					!More than one match
		RETURN .CMDI
		END
	END;
RETURN CMD_NOT_FOUND;		!Not in the table at all

END;
ROUTINE CMD_ENTRY_CHECK(CMD,ADDR,TC,SC)=
!Local routine to scan a single entry in the table
BEGIN
MAP ADDR: REF BLOCK FIELD(CMD_FIELDS);
LOCAL TPTR;	!Pointer to table entry
LOCAL SPTR;	!Pointer to user's string

SPTR=CH$PTR(.CMD);
TPTR=CH$PTR(.ADDR[CMD_TEXT_ADDR]);
WHILE ((.SC=CH$RCHAR_A(SPTR)) EQL (.TC=CH$RCHAR_A(TPTR))) DO 
	(IF ..TC EQL 0 THEN RETURN)
END;
END ELUDOM