Re: `argn' ? … still part of Octave?

[Carnë Draug]

On 24 October 2011 13:23, Ben Abbott <address@hidden> wrote:
> On Oct 24, 2011, at 6:09 AM, Carnë Draug wrote:
>
>> On 23 October 2011 19:21, Ben Abbott <address@hidden> wrote:
>>> On Oct 5, 2011, at 9:31 PM, Carnë Draug wrote:
>>>
>>>> On 6 October 2011 01:27, John W. Eaton <address@hidden> wrote:
>>>>> | idea is to use arg (or inputname) to get the name of the variable in
>>>>> | the caller and change its value with assignin('caller',...)
>>>>>
>>>>> OK, I guess you can try that, but it will be somewhat slow and
>>>>> it seems to me that it will definitely be clumsy.
>>>>
>>>> I know. But the class I'm trying to implement (inputParser) already
>>>> exists in MatLab. It's for the sake of compatibility. And I'm learning
>>>> something new in the process too :)
>>>>
>>>> Carnë
>>>
>>> Carnë,
>>>
>>> Any progress on implementing a compliant inputParser?
>>>
>>> I had contacted Nico Schlomer and cooperated with him to modify his 
>>> matlab2tikz to allow it to run on Octave. He had made good use of Matlab's 
>>> inputParser. The replacement used by matlab2tikz contains much of the same 
>>> functionality.
>>>
>>>        http://win.ua.ac.be/~nschloe/content/matlab2tikz
>>>
>>> You may find some code there that is helpful toward your effort (Take a 
>>> look at matlab2tikzInputParser.m)
>>
>> Hi Ben,
>>
>> yes. I finished it some days ago but I still need to write the
>> documentation and would like to test it a bit more before submitting
>> it ( https://gitorious.org/octave-devel/inputparser ). I do not have
>> matlab to test how compliant it is, I've just been following what they
>> have written on the inputParser documentation. Hopefully it'll be
>> ready sometime during next weekend.
>>
>> But thank you for the link. I looked on the way he did it and found it
>> very interesting how he mimicked an object by creating a struct with
>> fields that are simply function handles for functions that were only
>> in scope when the struct was created.
>>
>> Carnë
>
> The parser code now used by matalbtikz is mostly mine. I has originally tried 
> to do what you are working on. My original code with the "@inputParser" 
> directory is attached.
>
> There is a simple example from the ML docs below.
>
>       p = inputParser;
>
>       p.addRequired('a');
>       p.addOptional('b',1);
>       p.addParamValue('c',2);
>
>       p.parse(10, 20, 'c', 30);
>       res = p.Results
>
>       res =
>          a: 10
>          b: 20
>          c: 30
>
> I was unable to fake the self modifying methods (I'll take a look at how you 
> did that later today). Instead, my implementation works as ...
>
>       p = inputParser;
>
>       p = p.addRequired(p, 'a');
>       p = p.addOptional(p, 'b',1);
>       p = p.addParamValue(p, 'c',2);
>
>       p = p.parse(p, 10, 20, 'c', 30);
>       res = p.Results
>
>       res =
>          a: 10
>          b: 20
>          c: 30

Mine is working the same, it's nice to know the parsing seems
compatible (I used this function http://pastebin.com/AyvqMX12 to test
it that I got from the documentation online). I did manage an ugly
kludge to mimic the self modifying API but discussing it with jwe on
#octave, he didn't like it and he was right. For example, if the
object was stored inside a structure, my hack would actually replace
the whole structure. So in the end, I never applied it. It's commented
out on the code (pretty much all the class code is in subsref)

  ## the following at the end may allow to use the obj.method notation one day
  ## jwe is very against this ugly hack
  ## what would happen if the user has the obj inside a struct? Bad things!
#  ori = inputname(1);
#  assignin('caller', ori, inPar);

But matlab also has a p = addRequired (p, ...) type of API. My code
should also work fine if used that way so it should be possible to
write code that is 100% compatible.

octave:1> p = inputParser;
octave:2> p = addRequired(p, 'a');
octave:3> p = addOptional(p, 'b',1);
octave:4> p = addParamValue(p, 'c',2);
octave:5> p = parse(p, 10, 20, 'c', 30);
octave:6> res = p.Results
res =

  scalar structure containing the fields:

    a =  10
    b =  20
    c =  30


I won't have much time the next days and going to Dublin tomorrow, but
will look at it again on Thursday. I noticed that you also implemented
comparison operators for the class. Is that your "expansion" of the
class, or is it for compatibility with Matlab?

Carnë