bugGNU Octave - Bugs: bug #59377, Command syntax could be more...


bug #59377: Command syntax could be more clearly documented

Submitted by:  None
Submitted on:  Wed 28 Oct 2020 07:41:59 PM UTC  
Category:  Octave Function Severity:  3 - Normal
Priority:  5 - Normal Item Group:  Documentation
Status:  None Assigned to:  None
Originator Name:  Originator Email:  -email is unavailable-
Open/Closed:  Open Release:  dev
Operating System:  GNU/Linux

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Wed 28 Oct 2020 08:40:40 PM UTC, comment #3: 

The basics are documented here:

And fwiw in Matlab R2020b:

>> Inf -13

ans =


>> Inf - 13

ans =


Markus M├╝tzel <mmuetzel>
Project Member
Wed 28 Oct 2020 08:34:47 PM UTC, comment #2: 

OP here. I do not have Matlab, but I accept that if it's done with the aim of Matlab-compatibility that takes precedence over unexpected behavior.

Your other example with Inf did not work as described.

octave:105> Inf -13
ans = Inf
octave:106> Inf - 13
ans = Inf

Was one of them supposed to give an error?

Wed 28 Oct 2020 08:20:59 PM UTC, comment #1: 

It's a general feature of the langauge that could probably be more clearly documented.  If you call any function using "command" syntax, like

size 12345

It is parsed and evaluated as if you had written

size ("12345")

Any update to the docs should also attempt to explain the weird rules for Matlab compatible parsing of these kinds of expressions.  For example,

Inf -13   %% => Inf ('-13') => invalid call to Inf
Inf - 13  %% => subtraction => Inf() - 13

John W. Eaton <jwe>
Project Administrator
Wed 28 Oct 2020 07:41:59 PM UTC, original submission:  

The documentation for size only lists the function-like usage "size (foo)" or "size (foo, dim)" with optional output arguments. But the following command-like syntax turns out not to give an error on Octave 7.0.0:

octave:1> size 12345
ans =
   1   5

octave:2> size abcdef
ans =
   1   6

Reporting this as a missed error or warning in case this behavior was not intended.



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    Follow 2 latest changes.

    Date Changed by Updated Field Previous Value => Replaced by
    2020-10-28 jwe Item GroupMissed Error or Warning => Documentation
        SummaryUndocumented behavior for size, possibly a missed error or warning => Command syntax could be more clearly documented

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