type expression for polymorphic variant with open matching #8414

vicuna · 2003-12-16T01:53:27Z

Original bug ID: 1978
Reporter: administrator
Status: closed
Resolution: fixed
Priority: normal
Severity: minor
Category: ~DO NOT USE (was: OCaml general)

Bug description

Full_Name: Peter Hercek
Version: 3.07+2
OS: Linux
Submission from: ethernet-012-packplace.citizens.swva.net.66.37.66.in-addr.arpa (66.37.66.12)

Hi,

I checked it on Linux, but the behavior is the same on Windows with version
3.07.
This may be a documentation error and not an OCaml parser/lexer error. My report
is based on the pdf documentation for OCaml 3.07 (September 29, 2003).

Here is my test with OCaml console:
Objective Caml version 3.07+2

let f x:[<|`A|`B] = x;;

val f : ([< A | B ] as 'a) -> 'a =

let f x:[>|`A|`B] = x;;

Syntax error

let f x:[> |`A|`B] = x;;

#quit;;

It looks like the reason is that ">|" is a lexical symbol and "[>" is not a
lexical symbol.
Well, "[>" should not be lexical symbol based on the BNF grammar for
"variant-type" nonterminal. Uff, this reasoning is valid for "[<" too and "[<"
is a keyword (ie a lexical symbol). On the other side ">|" should not be a
lexical symbol, because there is no mention about in in the whole OCaml 3.07
manual.

Regards,
Peter.

The text was updated successfully, but these errors were encountered:

vicuna · 2003-12-18T16:28:59Z

Comment author: administrator

Objective Caml version 3.07+2

let f x:[<|A|B] = x;;

val f : ([< A | B ] as 'a) -> 'a =

let f x:[>|A|B] = x;;

Syntax error

let f x:[> |A|B] = x;;

[...]

It looks like the reason is that ">|" is a lexical symbol and "[>" is not a
lexical symbol.

That's how it is in the implementation now. I regard this as a design bug.
There is no reason for "[>" not to be a symbol while "[<" is a symbol.

Well, "[>" should not be lexical symbol based on the BNF grammar for
"variant-type" nonterminal.

The BNF grammar needs to be fixed.

On the other side ">|" should not be a
lexical symbol, because there is no mention about in in the whole OCaml 3.07
manual.

Your reasoning is incorrect. ">|" is an identifier, and we obvioulsy cannot
list
all valid identifiers in the manual...

I have fixed the problem in the CVS tree by giving "[>" the same status as
"[<".
We still have to fix the BNF grammar.

Thanks for your bug report,

-- Damien

vicuna · 2003-12-18T16:28:59Z

Comment author: administrator

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Action: failed
Status: 5.1.2
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Diagnostic-Code: SMTP; 550 Host unknown
Last-Attempt-Date: Thu, 18 Dec 2003 17:28:59 +0100 (MET)

Return-Path: caml-bugs@pauillac.inria.fr
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Date: Thu, 18 Dec 2003 17:28:57 +0100 (MET)
Message-Id: 200312181628.RAA16833@pauillac.inria.fr
From: Damien Doligez caml-bugs@pauillac.inria.fr
To: peter@syncad.dot.com
Subject: Re: type expression for polymorphic variant with open matching (#8414)
X-Loop: caml-bugs@pauillac.inria.fr
MIME-Version: 1.0

Objective Caml version 3.07+2

let f x:[<|A|B] = x;;

val f : ([< A | B ] as 'a) -> 'a =

let f x:[>|A|B] = x;;

Syntax error

let f x:[> |A|B] = x;;

[...]

It looks like the reason is that ">|" is a lexical symbol and "[>" is not a
lexical symbol.

That's how it is in the implementation now. I regard this as a design bug.
There is no reason for "[>" not to be a symbol while "[<" is a symbol.

Well, "[>" should not be lexical symbol based on the BNF grammar for
"variant-type" nonterminal.

The BNF grammar needs to be fixed.

On the other side ">|" should not be a
lexical symbol, because there is no mention about in in the whole OCaml 3.07
manual.

Your reasoning is incorrect. ">|" is an identifier, and we obvioulsy cannot
list
all valid identifiers in the manual...

I have fixed the problem in the CVS tree by giving "[>" the same status as
"[<".
We still have to fix the BNF grammar.

Thanks for your bug report,

-- Damien

vicuna · 2004-06-18T09:43:58Z

Comment author: administrator

implementation fixed --DD 2003-12-18
doc fixed --DD 2004-06-18

vicuna closed this as completed Jun 18, 2004

vicuna added the bug label Mar 19, 2019

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type expression for polymorphic variant with open matching #8414

type expression for polymorphic variant with open matching #8414

vicuna commented Dec 16, 2003

vicuna commented Dec 18, 2003

let f x:[<|`A|`B] = x;;

let f x:[>|`A|`B] = x;;

let f x:[> |`A|`B] = x;;

vicuna commented Dec 18, 2003

let f x:[<|`A|`B] = x;;

let f x:[>|`A|`B] = x;;

let f x:[> |`A|`B] = x;;

vicuna commented Jun 18, 2004

type expression for polymorphic variant with open matching #8414

type expression for polymorphic variant with open matching #8414

Comments

vicuna commented Dec 16, 2003

Bug description

let f x:[<|A|B] = x;;

let f x:[>|A|B] = x;;

let f x:[> |A|B] = x;;

#quit;;

vicuna commented Dec 18, 2003

let f x:[<|A|B] = x;;

let f x:[>|A|B] = x;;

let f x:[> |A|B] = x;;

vicuna commented Dec 18, 2003

let f x:[<|A|B] = x;;

let f x:[>|A|B] = x;;

let f x:[> |A|B] = x;;

vicuna commented Jun 18, 2004

let f x:[<|`A|`B] = x;;

let f x:[>|`A|`B] = x;;

let f x:[> |`A|`B] = x;;

let f x:[<|`A|`B] = x;;

let f x:[>|`A|`B] = x;;

let f x:[> |`A|`B] = x;;

let f x:[<|`A|`B] = x;;

let f x:[>|`A|`B] = x;;

let f x:[> |`A|`B] = x;;