0004705: Can't define types with `True or `False

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Date Submitted

Last Update

0004705

OCaml

Camlp4

public

2009-01-31 01:31

2012-09-25 20:06

Reporter

Martin Jambon

Assigned To

xclerc

Priority

normal

Severity

minor

Reproducibility

always

Status

closed

Resolution

fixed

Platform

OS Version

Product Version

3.11.0

Target Version

Fixed in Version

3.12.1+dev

Summary

0004705: Can't define types with `True or `False

Description

Quotations in the revised syntax do not handle `True or `False correctly in type definitions. It is very hard to guess since the type definition is processed and compiled without errors. The problems only occur when using the type in question.

Affected versions: 3.10.2, 3.11.0 with camlp4orf
Old Camlp4 3.09.2 works fine on that case.

$ ocamlc -c -pp camlp4orf -I +camlp4 pa_foo.ml
$ ocamlc -c -pp 'camlp4o -parser pa_foo.cmo' foo.ml
File "foo.ml", line 10, characters 1-7:
Error: This expression has type [> ` False ] but is here used with type foo
       The second variant type does not allow tag(s) ` False

(*
  This is pa_foo.ml

  ocamlc -c -pp camlp4orf -I +camlp4 pa_foo.ml
*)

open Camlp4.PreCast
open Syntax

EXTEND Gram
  GLOBAL: str_item;
  str_item: [
    [ "FOO" -> <:str_item< type foo = [ = `False ] >> ]
  ];
END
;;
(*********************************************************)

(*
  This is foo.ml

  camlp4o -parser pa_foo.cmo -printer o foo.ml
  ocamlc -c -pp 'camlp4o -parser pa_foo.cmo' foo.ml
*)

FOO ;;

(`False : foo)

(*********************************************************)

Pretty-printing goes well:

$ camlp4o -parser pa_foo.cmo -printer o foo.ml
(*
  This is foo.ml

  camlp4o -parser pa_foo.cmo -printer o foo.ml
  ocamlc -c -pp 'camlp4o -parser pa_foo.cmo' foo.ml
*)
type foo = [ | `False ]

let _ = (`False : foo)

---

So one first workaround is to preprocess files with 'camlp4o -printer o ...'.
Another workaround is to avoid using `True or `False.
A third workaround is to use quotations in the classic syntax.

Issue History
Date Modified	Username	Field	Change
2009-01-31 01:31	Martin Jambon	New Issue
2009-03-28 17:18	xleroy	Status	new => assigned
2009-03-28 17:18	xleroy	Assigned To	=> ertai
2011-09-05 15:38	xclerc	Assigned To	ertai => xclerc
2011-09-05 15:39	xclerc	Status	assigned => resolved
2011-09-05 15:39	xclerc	Fixed in Version	=> 3.12.1+dev
2011-09-05 15:39	xclerc	Resolution	open => fixed
2012-09-25 20:06	xleroy	Status	resolved => closed

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