MODULE env; (** AUTHOR "Yaroslav Romanchenko"; PURPOSE "Simple example of reading environment variables on Unix"; *)
 
IMPORT
	SYSTEM, Commands, Unix;
 
PROCEDURE GetEnvVar(aName: ARRAY OF CHAR; VAR aVar: ARRAY OF CHAR): BOOLEAN;
VAR
	addr: ADDRESS;
	i, max: LONGINT;
	c: CHAR;
	bOk: BOOLEAN;
BEGIN
	bOk := FALSE;
	max := LEN(aVar) - 1;
	(* For reading even one char we need at least array of length 2 *)
	IF max >= 1 THEN
		addr := Unix.getenv(ADDRESSOF(aName));
		IF addr = 0 THEN
			(* There is no such variable. Result is FALSE *)
			aVar[0] := 0X
		ELSE
			REPEAT
				SYSTEM.GET(addr, c);
				aVar[i] := c;
				INC(addr);
				INC(i)
			UNTIL (c = 0X) OR (i = max);
			aVar[i] := 0X;
			bOk := TRUE
		END
	END;
	RETURN bOk
END GetEnvVar;
 
PROCEDURE var*(context: Commands.Context);
VAR
	aName, aVar: ARRAY 256 OF CHAR;
BEGIN
	context.arg.SkipWhitespace();
	context.arg.Token(aName);
	IF (aName[0] # 0X) & GetEnvVar(aName, aVar) THEN
		context.out.String(aName);
		context.out.Char('=');
		context.out.String(aVar);
		context.out.Ln
	END;
END var;
 
END env.