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April 18, 2009
Re: Fully dynamic d by opDotExp overloading
Andrei Alexandrescu:
> Pascalize!S s;
> s.foo(); // works
> s.Foo(); // works too
> s.fOo(); // yup, works again

I can show something even more extreme :-)

What we are discussing in this thread is named the __getattr__ method in Python:
http://docs.python.org/reference/datamodel.html#object.__getattr__

Note that in Python there's something even more powerful, __getattribute__:
http://docs.python.org/reference/datamodel.html#object.__getattribute__

So I have created this, that I actually use in a large Graph class of mine that has many methods:
http://code.activestate.com/recipes/409000/
Such class can be used from the interactive shell too, to play with graphs in an interactive way, modify them, plot them, etc.
Often you may not remember the name of a method you need, or you may mistype it. In such situation __getattr__ is being called. It collects the class method names, removed the useless ones, and performs a similarity search between the given wrong method name and the strings in that list. Then returns the 4-5 most similar ones, each one followed by their docstring, that shows the function signature and the purpose of the method. So you can usually find the method you were looking for, and use it. This is useful both when using such Graph class from the command line and when you are writing code without an IDE that helps you finding method names.
That Python code of mine becomes doable in D too (using for example my very fast approximate string distance. This is a case where you don't need the list of changes, but just the distance number. So superdan can rest in peace).

Bye,
bearophile
April 18, 2009
Re: Fully dynamic d by opDotExp overloading
bearophile wrote:
> Andrei Alexandrescu:
>> Pascalize!S s;
>> s.foo(); // works
>> s.Foo(); // works too
>> s.fOo(); // yup, works again
> 
> I can show something even more extreme :-)
> 
> What we are discussing in this thread is named the __getattr__ method in Python:
> http://docs.python.org/reference/datamodel.html#object.__getattr__
> 
> Note that in Python there's something even more powerful, __getattribute__:
> http://docs.python.org/reference/datamodel.html#object.__getattribute__
> 
> So I have created this, that I actually use in a large Graph class of mine that has many methods:
> http://code.activestate.com/recipes/409000/
> Such class can be used from the interactive shell too, to play with graphs in an interactive way, modify them, plot them, etc.
> Often you may not remember the name of a method you need, or you may mistype it. In such situation __getattr__ is being called. It collects the class method names, removed the useless ones, and performs a similarity search between the given wrong method name and the strings in that list. Then returns the 4-5 most similar ones, each one followed by their docstring, that shows the function signature and the purpose of the method. So you can usually find the method you were looking for, and use it. This is useful both when using such Graph class from the command line and when you are writing code without an IDE that helps you finding method names.
> That Python code of mine becomes doable in D too (using for example my very fast approximate string distance. This is a case where you don't need the list of changes, but just the distance number. So superdan can rest in peace).
> 
> Bye,
> bearophile

There's an interesting idea...

Instead of "No member 'foo'", you could have "No member 'foo'; did you
mean 'far' or 'fur'?"

 -- Daniel
April 18, 2009
Re: Fully dynamic d by opDotExp overloading
Daniel Keep wrote:
> 
> bearophile wrote:
>> Andrei Alexandrescu:
>>> Pascalize!S s;
>>> s.foo(); // works
>>> s.Foo(); // works too
>>> s.fOo(); // yup, works again
>> I can show something even more extreme :-)
>>
>> What we are discussing in this thread is named the __getattr__ method in Python:
>> http://docs.python.org/reference/datamodel.html#object.__getattr__
>>
>> Note that in Python there's something even more powerful, __getattribute__:
>> http://docs.python.org/reference/datamodel.html#object.__getattribute__
>>
>> So I have created this, that I actually use in a large Graph class of mine that has many methods:
>> http://code.activestate.com/recipes/409000/
>> Such class can be used from the interactive shell too, to play with graphs in an interactive way, modify them, plot them, etc.
>> Often you may not remember the name of a method you need, or you may mistype it. In such situation __getattr__ is being called. It collects the class method names, removed the useless ones, and performs a similarity search between the given wrong method name and the strings in that list. Then returns the 4-5 most similar ones, each one followed by their docstring, that shows the function signature and the purpose of the method. So you can usually find the method you were looking for, and use it. This is useful both when using such Graph class from the command line and when you are writing code without an IDE that helps you finding method names.
>> That Python code of mine becomes doable in D too (using for example my very fast approximate string distance. This is a case where you don't need the list of changes, but just the distance number. So superdan can rest in peace).
>>
>> Bye,
>> bearophile
> 
> There's an interesting idea...
> 
> Instead of "No member 'foo'", you could have "No member 'foo'; did you
> mean 'far' or 'fur'?"
> 
>   -- Daniel

Heh. The string kernels in std.numeric 
(http://erdani.dreamhosters.com/d/web/phobos/std_numeric.html) are to 
help with exactly that.

Andrei
April 18, 2009
Re: Fully dynamic d by opDotExp overloading
Daniel Keep, el 18 de abril a las 19:08 me escribiste:
> > So I have created this, that I actually use in a large Graph class of mine that has many methods:
> > http://code.activestate.com/recipes/409000/
> > Such class can be used from the interactive shell too, to play with graphs in an interactive way, modify them, plot them, etc.
> > Often you may not remember the name of a method you need, or you may
> > mistype it. In such situation __getattr__ is being called. It collects
> > the class method names, removed the useless ones, and performs
> > a similarity search between the given wrong method name and the
> > strings in that list. Then returns the 4-5 most similar ones, each one
> > followed by their docstring, that shows the function signature and the
> > purpose of the method. So you can usually find the method you were
> > looking for, and use it. This is useful both when using such Graph
> > class from the command line and when you are writing code without an
> > IDE that helps you finding method names.  That Python code of mine
> > becomes doable in D too (using for example my very fast approximate
> > string distance. This is a case where you don't need the list of
> > changes, but just the distance number. So superdan can rest in peace).
> > 
> > Bye,
> > bearophile
> 
> There's an interesting idea...
> 
> Instead of "No member 'foo'", you could have "No member 'foo'; did you
> mean 'far' or 'fur'?"

Git[1] added that feature for Git commands recently and even when it's not
really *that* useful, is a nice feature =)

Maybe something like "candidates are: ..." following by each method and
file location (to empower IDEs) can be done.

I mean, the DMD frontend could do that, not opDot(Exp), of course ;)

-- 
Leandro Lucarella (luca) | Blog colectivo: http://www.mazziblog.com.ar/blog/
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----------------------------------------------------------------------------
Software is like sex: it's better when it's free.
	-- Linus Torvalds
April 18, 2009
Re: Fully dynamic d by opDotExp overloading
Andrei Alexandrescu wrote:
> Daniel Keep wrote:
>> There's an interesting idea...
>>
>> Instead of "No member 'foo'", you could have "No member 'foo'; did you
>> mean 'far' or 'fur'?"
> 
> Heh. The string kernels in std.numeric 
> (http://erdani.dreamhosters.com/d/web/phobos/std_numeric.html) are to 
> help with exactly that.

I remember, but can't find, some famous programmer posted to the net a 
simple spell checking algorithm that worked by counting letter 
additions, deletions, and transpositions to determine best matches.
April 18, 2009
Re: Fully dynamic d by opDotExp overloading
Walter Bright wrote:
> Andrei Alexandrescu wrote:
>> Daniel Keep wrote:
>>> There's an interesting idea...
>>>
>>> Instead of "No member 'foo'", you could have "No member 'foo'; did you
>>> mean 'far' or 'fur'?"
>>
>> Heh. The string kernels in std.numeric 
>> (http://erdani.dreamhosters.com/d/web/phobos/std_numeric.html) are to 
>> help with exactly that.
> 
> I remember, but can't find, some famous programmer posted to the net a 
> simple spell checking algorithm that worked by counting letter 
> additions, deletions, and transpositions to determine best matches.

I don't know who the famous programmer was but it sounds like he was 
referring to one of the edit distances. std.algorithm has an 
implementation of the popular Levenshtein distance.

http://erdani.dreamhosters.com/d/web/phobos/std_algorithm.html#levenshteinDistance

String kernels go way beyond that because they count the weighted length 
of all gapped substrings common to two strings.

http://erdani.dreamhosters.com/d/web/phobos/std_numeric.html#gapWeightedSimilarity

With such a similarity, more subtle errors can be detected.


Andrei
April 19, 2009
Re: Fully dynamic d by opDotExp overloading
A simple command line spell checker would be a cool demonstration of this!
April 19, 2009
Re: Fully dynamic d by opDotExp overloading
Walter Bright wrote:
> A simple command line spell checker would be a cool demonstration of this!

$ man bash
/cdspell

  If set, minor errors in the spelling of a directory com-
  ponent in a cd command will be  corrected.   The  errors
  checked for are transposed characters, a missing charac-
  ter, and one character too many.   If  a  correction  is
  found,  the corrected file name is printed, and the com-
  mand proceeds.  This option is only used by  interactive
  shells.
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