M2compiler-V3/compiler/tests/t_compat.mod

MODULE TCompat;
// GNU/classic compatibility accepted by V3 for self-hosting the
// Coco/R-generated sources: '&' (AND) and '~' (NOT), LENGTH (alias of
// LEN), CAP, the octal character literal 0C, and empty THEN/ELSE
// bodies. Exit 42.
VAR ExitCode : INTEGER;
VAR s : ARRAY [0..2] OF CHAR;
VAR c : CHAR;
VAR n : INTEGER;

PROCEDURE Len (a : ARRAY OF CHAR) : INTEGER;
BEGIN RETURN LENGTH(a) END Len;

BEGIN
  s := "abc";
  n := Len(s);                       // 3 (LENGTH alias)
  c := CAP("q");                     // 'Q'
  IF (n = 3) & (c = "Q") THEN
    n := n + 39                      // & = AND -> 42
  ELSE
  END;                               // empty ELSE
  c := 0C;                           // octal char literal -> NUL
  IF ~(c = CHR(0)) THEN n := 0 END;  // ~ = NOT
  IF n = 42 THEN ELSE n := 0 END;    // empty THEN + ELSE
  ExitCode := n
END TCompat.