[Caml-list] camlp4: generating keyword on the fly

["Jeff Henrikson" <jehenrik@yahoo.com>]

I want to be able to cook up keywords on the fly using camlp4, and it seems like I should be able to do it.  But this is as far as
I get.  This function compiles:


let make_one_item_entry entrysym (keyword : string) =
  let tmp = (Grammar.Entry.create Pcaml.gram entrysym) in
  EXTEND
    tmp: [ [ "birthday" ] ]
    ;
  END;
  tmp;;

Grammar.Entry.print (make_one_item_entry "happy" "birthday");;

# [ LEFTA
  [ "birthday" ] ]
- : unit = ()


But this one does not:


let make_one_item_entry entrysym (keyword : string) =
  let tmp = (Grammar.Entry.create Pcaml.gram entrysym) in
  EXTEND
    tmp: [ [ keyword ] ]
    ;
  END;
  tmp;;

Grammar.Entry.print (make_one_item_entry "happy" "birthday");;


Note that this looks right but isn't:


let make_one_item_entry entrysym (keyword : string) =
  let tmp = (Grammar.Entry.create Pcaml.gram entrysym) in
  let tmp2 = (Grammar.Entry.create Pcaml.gram keyword) in
  EXTEND
    tmp: [ [ tmp2 ] ]
    ;
  END;
  tmp;;

Grammar.Entry.print (make_one_item_entry "happy" "birthday");;

# [ LEFTA
  [ birthday ] ]
- : unit = ()


(The quotes are missing)  I'm new at camlp4, so I don't know if my jargon for explaining this is right, but:

I can get an empty entry with Grammar.Entry.create, but the only way to extend it seems to be with EXTEND which so far as I can see
only takes string constants.  Does this make sense?


Jeff Henrikson


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