(****************************************************************)
	(* InputEnv.mod							*)
	(* Version 2.0 of InputEnv					*)
	(* Versions 1.0, 1.1 written in C;				*)
	(* Versions 2.0 and above written in Modula-2			*)
	(* Copyright © 1994 John E> Perry, ///				*)
	(* This program and its source are freely distributable		*)
 	(****************************************************************)
	(* This program is a DOS interface, with prompting, for the	*)
	(* user to set an environment variable.  For example, I use it	*)
	(* in my S:Shell-Startup file like so:				*)
	(*								*)
	(* InputEnv SUPPRESS SHELL UserName Please input your name:	*)
	(* Prompt "$UserName @ *E[1m$Hostname*E[0m : *E[33;3m%S*E[0m> "	*)
	(*								*)
	(* which gives the prompt (special styles excluded :)		*)
	(*								*)
	(*	jack@Sara : >						*)
	(*								*)
	(* for whatever shell I'm using.  (Sara is the name of my Amiga.*)
 	(****************************************************************)
	(* Suggestions, Bugs, Questions, Comments, Snide Remarks, Etc.:	*)
	(*			jep@nauvax.ucc.nau.edu			*)
 	(****************************************************************)

MODULE InputEnv;
 
 	(****************************************************************)
	(* Imported modules.						*)
 	(****************************************************************)
   
  FROM System IMPORT argv, argc;
  FROM SYSTEM IMPORT ADDRESS, ADR;
  FROM Terminal IMPORT WriteString, WriteLn, Write, Read;
  FROM Strings IMPORT ConcatString, CompareString, Relation, StringLength;
  FROM AmigaDOS2 IMPORT SetVar, GVBLocalOnly, GVBGlobalOnly,
		DOSVariableFlagsSet, GetVar;
 
 	(****************************************************************)
	(* Programmer-defined constants.				*)
	(* These are special characters that I need to define like so	*)
	(* in order to achieve various desired effects with a Write.	*)
	(* Or... defined for my convenience.				*)
 	(****************************************************************)
  CONST
    EOS = CHAR(0);	(* end of string	*)
    TAB = CHAR(9);	(* tab			*)
    EOL = CHAR(10);	(* end of line		*)
    ESC = CHAR(27);	(* escape		*)
 
 	(****************************************************************)
	(* Module Variables.						*)
	(* yesNo: an input variable (yes or no)				*)
	(* counter: a string counter					*)
	(* envVar: name of the environment variable being created	*)
	(* envString: string AmigaDOS is to associate with envVar	*)
	(* suppressFlag: suppress "...overwrite?" prompt?		*)
	(* shellFlag: shell or globale environment variable?		*)
	(* promptString: how to prompt user				*)
	(* argString: used to point to command-line arguments		*)
 	(****************************************************************)
  VAR
    yesNo: CHAR;
    counter: CARDINAL;
    envVar: ARRAY[0..63] OF CHAR;
    envString: ARRAY[0..255] OF CHAR;
    suppressFlag, shellFlag: BOOLEAN;
    promptString: ARRAY[0..127] OF CHAR;
    argString: POINTER TO ARRAY [0..63] OF CHAR;
 
 	(****************************************************************)
	(* PROCEDURE ReadLn(VAR string: ARRAY OF CHAR);			*)
	(* Reads string until EOL is encountered.			*)
 	(****************************************************************)
  PROCEDURE ReadLn(VAR string: ARRAY OF CHAR);
    VAR
      in: CHAR;		(* input character	*)
      loc: CARDINAL;	(* location in string	*)
    BEGIN
      loc := 0;
      in := CHAR(0);
      (* read string *)
      WHILE in # CHAR(10)
        DO
	  Read(in);
	  string[loc] := in;
	  INC(loc);
	END; (* WHILE *)
      string[loc - 1] := CHAR(0);
    END ReadLn;
 
  BEGIN
    IF argc = 1
      THEN
        WriteString('Dude! The usage is:'); WriteLn;
        Write(TAB); WriteString('InputEnv [SUPPRESS] [SHELL] <envname> <prompt>'); 
	WriteLn;
        WriteString('where <envname> is the name of the environment string and'); 
	WriteLn;
        WriteString('<prompt> is the prompt for the user.  ');
	Write(ESC); 
	WriteString('[3mNOTE THAT <prompt> MUST'); WriteLn;
        WriteString('BE THE LAST THING ON THE LINE, AND <envname> ');
	Write(ESC); 
	WriteString('[1mMUST '); 
	Write(ESC);
	WriteString('[22m BE NEXT TO LAST!!!');
	Write(ESC);
	WriteString('[23m'); 
	WriteLn;
        Write(TAB); 
	WriteString('To suppress verification of new environment variable,'); 
	WriteLn;
        WriteString('use SUPPRESS, and to make a shell instead of a global'); 
	WriteLn;
        WriteString('environment variable, user SHELL.'); 
	WriteLn;
	WriteLn;
        WriteString('InputEnv v2.0 Copyright © 1994 John E> Perry, ///'); WriteLn;
	HALT;
      END; (* IF *)
    (* process command line *)
    counter := 1;
    argString := ADDRESS(argv^[1]);
    (* suppress "...overwrite?" prompt? *)
    IF CompareString(argString^, 'SUPPRESS') = equal
      THEN
        suppressFlag := TRUE;
	INC(counter);
      END; (* IF *)
    argString := ADDRESS(argv^[counter]);
    (* shell variable? default is global *)
    IF CompareString(argString^, 'SHELL') = equal
      THEN
	shellFlag := TRUE;
	INC(counter);
      END; (* IF *)
    ConcatString(envVar, argv^[counter]^);
    INC(counter);
    (* prompt *)
    WHILE counter <= (argc - 1)
      DO
        ConcatString(promptString, argv^[counter]^);
        ConcatString(promptString, ' ');
	INC(counter);
      END; (* WHILE *)
    (* get string *)
    WriteString(promptString);
    ReadLn(envString);
    (* check to see if variable exists *)
    IF NOT suppressFlag
      THEN
        IF NOT ((GetVar(ADR(envVar), ADR(promptString), 63, DOSVariableFlagsSet {GVBGlobalOnly}) = LONGINT(-1DH)) OR (GetVar(ADR(envVar), ADR(promptString), 63, DOSVariableFlagsSet {GVBLocalOnly}) = LONGINT(-1DH)))
	  THEN
	    WriteString('Variable already exists! overwrite? (Y/N) ');
	    Read(yesNo);
	    IF (yesNo = 'N') OR (yesNo = 'n')
	      THEN
	        HALT;
	      END; (* IF *)
	  END; (* IF *)
      END; (* IF *)
    (* okay, write it out *)
    IF shellFlag
      THEN
	shellFlag := SetVar(ADR(envVar), ADR(envString), LONGINT(StringLength(envString)), DOSVariableFlagsSet{GVBLocalOnly});
      ELSE
	shellFlag := SetVar(ADR(envVar), ADR(envString), LONGINT(StringLength(envString)), DOSVariableFlagsSet{GVBGlobalOnly});
      END; (* IF *)
  END InputEnv.