IMPLEMENTATION MODULE CodeGen;

IMPORT FileIO;

VAR
  out    : FileIO.File;
  level  : INTEGER;
  opened : BOOLEAN;

PROCEDURE Append (VAR dest: ARRAY OF CHAR; src: ARRAY OF CHAR);
  VAR i, j : CARDINAL;
  BEGIN
    i := 0;
    WHILE dest[i] # 0C DO INC(i) END;
    j := 0;
    WHILE (i < HIGH(dest)) & (src[j] # 0C) DO
      dest[i] := src[j]; INC(i); INC(j)
    END;
    dest[i] := 0C
  END Append;

PROCEDURE OpenModule (name: ARRAY OF CHAR);
  VAR fname : ARRAY [0 .. 127] OF CHAR;
  BEGIN
    fname[0] := 0C;
    Append(fname, "gen/");
    Append(fname, name);
    Append(fname, ".mod");
    FileIO.Open(out, fname, TRUE);
    opened := FileIO.Okay;
    level := 0;
    IF opened THEN
      FileIO.WriteString(out, "(* Generated by SimpleM backend *)");
      FileIO.WriteLn(out)
    END
  END OpenModule;

PROCEDURE Close;
  BEGIN
    IF opened THEN FileIO.Close(out); opened := FALSE END
  END Close;

PROCEDURE Emit (s: ARRAY OF CHAR);
  BEGIN
    IF opened THEN FileIO.WriteString(out, s) END
  END Emit;

PROCEDURE Brk;
  VAR i : INTEGER;
  BEGIN
    IF ~opened THEN RETURN END;
    FileIO.WriteLn(out);
    i := 0;
    WHILE i < level * 2 DO FileIO.Write(out, " "); INC(i) END
  END Brk;

PROCEDURE Ind;
  BEGIN
    INC(level)
  END Ind;

PROCEDURE Ded;
  BEGIN
    IF level > 0 THEN DEC(level) END
  END Ded;

BEGIN
  opened := FALSE;
  level := 0
END CodeGen.