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Changes to lexer invalidate documentation
From: |
John W. Eaton |
Subject: |
Changes to lexer invalidate documentation |
Date: |
Sun, 12 Apr 2009 18:01:36 -0500 |
On 12-Apr-2009, Rik wrote:
| The parser has changed and the new output is:
| ---------------------
| functon y = f (x) y = x^2; endfunction
| parse error:
|
| syntax error
|
| >>> functon y = f (x) y = x^2; endfunction
This is valid through the ";", so I think the parser is doing the best
it can. For example, try this:
functon y = f (x) y = x^2;
and you'll see
error: `functon' undefined near line 1 column 1
So the syntax of this much is valid and the problem is that there is
no function called "functon" available to call. Then there is a
syntax error when the parser sees "endfunction" as an expression by
itself.
| I would argue that this is less desirable than the old behavior.
I think we're comparing different things. With an older version of
Octave, try
mark_as_command functon
functon y = f (x) y = x^2;
and you should see a message similar to what the current Octave
produces.
| indicating the error at the end of line it gives no clue where the real
| problem lies.
Octave doesn't try to guess that the functio name is misspelled, so
unless we decide to implement something like that (I'd rather not)
then I think it is the best we can do.
| I used hg bisect to track down the changeset which
| introduced the new behavior (changset 5dd06f19e9be).
Thanks, that helped me understand quickly why we see the new
behavior.
| If the new
| behavior can't be corrected it might be better to find a new error
| example which shows off the parser in a better light.
Yes, I agree that the behavior of this example is too complex for an
introduction to error messages. It would be better to have something
simpler.
Thanks,
jwe
- Changes to lexer invalidate documentation, Rik, 2009/04/12
- Changes to lexer invalidate documentation,
John W. Eaton <=
- Re: Changes to lexer invalidate documentation, Rik, 2009/04/12
- Re: Changes to lexer invalidate documentation, John W. Eaton, 2009/04/12
- Re: Changes to lexer invalidate documentation, Rik, 2009/04/13
- Re: Changes to lexer invalidate documentation, John W. Eaton, 2009/04/13
- Re: Changes to lexer invalidate documentation, Rik, 2009/04/13
- Re: Changes to lexer invalidate documentation, John W. Eaton, 2009/04/13