bugGNU Octave - Bugs: bug #38758, Parser oddity with 'if' statements...

 
 

bug #38758: Parser oddity with 'if' statements and spurious display with nargin

Submitted by:  Guillaume <gyom>
Submitted on:  Wed 17 Apr 2013 11:25:53 AM UTC  
 
Category:  Interpreter Severity:  3 - Normal
Priority:  5 - Normal Item Group:  Other
Status:  Fixed Assigned to:  John W. Eaton <jwe>
Originator Name:  Guillaume Open/Closed:  Closed
Release:  dev Operating System:  Any

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Thu 20 Jun 2013 02:13:10 AM UTC, comment #3:

I checked in the following change.

http://hg.savannah.gnu.org/hgweb/octave/rev/0bf1d559b321

John W. Eaton <jwe>
Project AdministratorIn charge of this item.
Wed 19 Jun 2013 10:46:18 PM UTC, comment #2:

I think the problem is also related to the path the parser is taking through if statements. For example, using a pair of parentheses around the condition of the if statement also fixes the problem.

Ordinarily code of the form

STATEMENT1, STATEMENT2

is equivalent to

STATEMENT1
STATEMENT2

as the comma just tells the parser that a new statement has begun. This seems to be the case here for whatever reason.

In fact, I would guess that the problem is that the if conditional is not being greedy enough and stops after accepting nargin. Thus, the parsing results in

Rik <rik5>
Project Administrator
Sat 11 May 2013 10:06:44 AM UTC, comment #1:

Confirmed.

Clemens Buchacher <drizzd>
Wed 17 Apr 2013 11:25:53 AM UTC, original submission:

Since recent changes in the Octave parser, I observe spurious displays due to lines such as:

it displays:

It doesn't happen with different call syntax:

Guillaume <gyom>

 

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    Follow 6 latest changes.

    Date Changed by Updated Field Previous Value => Replaced by
    2013-06-20 jwe StatusConfirmed => Fixed
        Open/ClosedOpen => Closed
    2013-06-19 jwe Assigned toNone => jwe
    2013-06-19 rik5 SummarySpurious display with nargin => Parser oddity with 'if' statements and spurious display with nargin
        Carbon-Copy- => Added jwe
    2013-05-11 jordigh StatusNone => Confirmed

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