Extend the q_symbol preprocessor to add a DEBUG directive.

Makefile.distrib

@@ -67,9 +67,9 @@ ifeq ($(INTERFACE), true)
 	OPT += -passopt -i
 endif
 
-ifeq ($(DEBUG), true)
+ifneq ($(strip $(DEBUG)),)
      OPT += -g
-     SYNTAX += -symbol DEBUG=\"1\"
+     SYNTAX += -symbol cduce_debug=\"$(DEBUG)\"
 endif
 
 OCAMLFIND = ocamlfind

misc/q_symbol.ml

@@ -2,20 +2,43 @@ open Camlp4.PreCast
 module Caml_syntax = Syntax
 
 let symbols = ref []
+let debug_symbols = ref []
+let debug = ref false
+
+let split_string c s =
+  let res = ref [] in
+  let buff = Buffer.create 32 in
+  let add s = if s <> "" then res:= s :: !res in
+  for i = 0 to String.length s - 1 do
+    match s.[i] with
+      d when d == c -> let f = Buffer.contents buff in
+                     Buffer.clear buff; add f
+    | ('a'..'z' | '0'..'9' | '_' | 'A'..'Z') as d  -> Buffer.add_char buff d
+    | _ -> ()
+  done;
+  let f = Buffer.contents buff in
+  add f;
+  !res
 
 let define s =
-  let i = 
-    try String.index s '=' 
+  let i =
+    try String.index s '='
     with Not_found -> failwith ("Invalid symbol definition :" ^ s) in
   let symbol = String.sub s 0 i in
+  let value_str = String.sub s (i + 1) (String.length s - i - 1) in
   let value =
     Gram.parse_string
-      Caml_syntax.expr (Loc.mk "<from-string>") (String.sub s (i + 1) (String.length s - i - 1))
+      Caml_syntax.expr (Loc.mk "<from-string>") value_str
   in
-  symbols := (symbol, value) :: !symbols
+  symbols := (symbol, value) :: !symbols;
+  if symbol = "cduce_debug" then begin
+    debug := true;
+    let l = split_string ',' value_str in
+    debug_symbols := l @ !debug_symbols
+  end
 
 EXTEND Caml_syntax.Gram
-  GLOBAL: Caml_syntax.str_item;
+  GLOBAL: Caml_syntax.str_item  Caml_syntax.expr;
 
   Caml_syntax.str_item: FIRST
     [ [ "ifdef"; c = UIDENT; "then"; e1 = SELF;
@@ -29,6 +52,22 @@ EXTEND Caml_syntax.Gram
       | "ifndef"; c = UIDENT; "then"; e1 = SELF ->
           if List.mem_assoc c !symbols then <:str_item<>> else e1
       ] ];
+
+  Caml_syntax.expr: BEFORE "simple"
+    [ [
+      "DEBUG" ; x = OPT [ x = LIDENT  -> x ]; "("; e = Caml_syntax.expr; ")"  ->
+      let flag =
+        match x with
+        None -> ""
+        | Some s -> s
+      in
+      let test = !debug && (flag = "" || List.mem flag !debug_symbols) in
+      Format.eprintf "Found Debug symbol %s, test = %b @\n%!" flag test;
+      if test then
+        e
+      else <:expr< () >>
+    ]
+    ];
 END
 
 let expr _ _ s =
@@ -37,5 +76,5 @@ let expr _ _ s =
 
 let _ =
   Quotation.add "symbol" Quotation.DynAst.expr_tag expr;
-  Camlp4.Options.add "-symbol" (Arg.String define) 
+  Camlp4.Options.add "-symbol" (Arg.String define)
     "<symbol=value> Define a symbol"