Console

For logging within the BlackBox framework, in particular the text subsystem, or for logging in very low-level modules the standard BlackBox logging facilities (Log, StdLog) cannot be used.

The following module 'Console' can be used for that purpose. It attaches a Windows Console window to the BlackBox process and outputs the log to the Console window. In order to make it easy to detect new output it adds a line number at the left. In order to increase readability it supports indentation of the output. Non-ASCII characters are converted to the underlying Windows default code page.

MODULE Console;

(* low level logging to console window; supports switching on and off and indentation.
   if used in Kernel (or other linked module) don't forget to link a new .exe file *)

IMPORT WinApi, SYSTEM;

VAR
	res, stdOut, lineNr, indent, offAtLineNr: INTEGER;
	on: BOOLEAN;
	indentStr: ARRAY 10 OF CHAR;

(* sets a non-default indent string, default is "  " *)
PROCEDURE SetIndentString*(IN s: ARRAY OF CHAR);
BEGIN
	indentStr := s$
END SetIndentString;

(* turn logging on; default *)
PROCEDURE On*;
BEGIN
	offAtLineNr := -1;
	on := TRUE
END On;

(* turn logging on for the specified number of lines *)
PROCEDURE OnFor*(nofLines: INTEGER);
BEGIN
	offAtLineNr := lineNr + nofLines;
	on := TRUE
END OnFor;

(* turn logging off *)
PROCEDURE Off*;
BEGIN
	on := FALSE
END Off;

(* increment indentation level *)
PROCEDURE Indent*;
BEGIN
	INC(indent)
END Indent;

(* decrement indentation level *)
PROCEDURE Undent*;
BEGIN
	DEC(indent)
END Undent;

(* output null terminated string; converted to Windows default code page *)
PROCEDURE String*(IN s: ARRAY OF CHAR);
	VAR buf: ARRAY 10000 OF SHORTCHAR;
BEGIN
	IF on & (s # "") THEN
		res := WinApi.WideCharToMultiByte(WinApi.CP_OEMCP, {}, s, LEN(s$), buf, LEN(buf), NIL, NIL);
		IF ~((res > 0) & (res <= LEN(buf))) THEN
			buf := "*** error in Console.String ***"; res := LEN(buf$);
		END;
		res := WinApi.WriteFile(stdOut, SYSTEM.ADR(buf), res, NIL, NIL)
	END
END String;

PROCEDURE IntToString(x: LONGINT; OUT s: ARRAY OF CHAR); (* copied from Strings *)
	CONST minLongIntRev = "8085774586302733229";
	VAR j, k: INTEGER; ch: CHAR; a: ARRAY 32 OF CHAR;
BEGIN
	IF x # MIN(LONGINT) THEN
		IF x < 0 THEN s[0] := "-"; k := 1; x := -x ELSE k := 0 END;
		j := 0; REPEAT a[j] := CHR(x MOD 10 + ORD("0")); x := x DIV 10; INC(j) UNTIL x = 0
	ELSE
		a := minLongIntRev; s[0] := "-"; k := 1;
		j := 0; WHILE a[j] # 0X DO INC(j) END
	END;
	ASSERT(k + j < LEN(s), 23);
	REPEAT DEC(j); ch := a[j]; s[k] := ch; INC(k) UNTIL j = 0;
	s[k] := 0X
END IntToString;

(* output integer as decimal number without any padding *)
PROCEDURE Int*(x: INTEGER);
	VAR str: ARRAY 20 OF CHAR; sstr: ARRAY 20 OF SHORTCHAR;
BEGIN
	IF on THEN
		IntToString(x, str);
		sstr := SHORT(str);
		res := WinApi.WriteFile(stdOut, SYSTEM.ADR(sstr), LEN(sstr$), NIL, NIL)
	END
END Int;

(* outputs the line number and indentation level followed by repeated indentStr according to the indentation level *)
PROCEDURE LinePrefix;
	VAR i: INTEGER;
BEGIN
	Int(lineNr); String(":"); Int(indent);
	FOR i := 1 TO indent DO String(indentStr) END
END LinePrefix;

(* output line end and increment line number *)
PROCEDURE Ln*;
	VAR crlf: ARRAY 2 OF SHORTCHAR;
BEGIN
	IF on THEN
		crlf[0] := 0DX; crlf[1] := 0AX;
		res := WinApi.WriteFile(stdOut, SYSTEM.ADR(crlf), 2, NIL, NIL);
		INC(lineNr); LinePrefix;
		IF (offAtLineNr # -1) & (lineNr = offAtLineNr) THEN on := FALSE END
	END
END Ln;

BEGIN
	res := WinApi.AllocConsole();
	stdOut := WinApi.GetStdHandle(WinApi.STD_OUTPUT_HANDLE);
	lineNr := 1; indent := 1; indentStr := "  "; On;
	LinePrefix
END Console.