Make autocall regexp's configurable.

[bfroehle]

As discussed in #81, there is some (small) demand that that the autocall regular expressions be configurable. For example:

$ ipython --AutocallChecker.exclude_regexp='^[,&^\\|\\*/]|^is |^not |^in |^and |^or ' --autocall=2
Python 2.7.3 (default, Apr 20 2012, 22:39:59) 
Type "copyright", "credits" or "license" for more information.

IPython 0.13.dev -- An enhanced Interactive Python.
?         -> Introduction and overview of IPython's features.
%quickref -> Quick reference.
help      -> Python's own help system.
object?   -> Details about 'object', use 'object??' for extra details.

In [1]: def f(*args): print args

In [2]: f -1
------> f(-1)
(-1,)

The attached pull request:

1. Creates a new trait type "CRegExp" which casts a string or regular expression into a compiled regular expression.
2. Makes the autocall regular expressions, which are only used in AutocallChecker configurable.

[bfroehle]

I should mention that even with this change I cannot get f +1 to convert to f(+1), but that seems beyond the scope here.

In [3]: f +1
---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
/home/bfroehle/src/ipython/<ipython-input-3-14b45bdc9b4b> in <module>()
----> 1 f +1

TypeError: unsupported operand type(s) for +: 'function' and 'int'

[takluyver]

Could you add tests for one or both of these parts? Thanks.

[takluyver]

Test results for commit d1f107f merged into master
Platform: linux2

• python2.7: OK
• python3.1: OK (libraries not available: matplotlib pymongo qt wx wx.aui zmq)
• python3.2: OK (libraries not available: pymongo wx wx.aui)

Not available for testing: python2.6

[bfroehle]

Could you add tests for one or both of these parts? Thanks.

Yes, see attached. There might be an easier way to do so, but I ended up creating a new AutocallChecker instance and adding it to the top of the list of checkers in ip.prefilter_manger.

[bfroehle]

Test results for commit 9d723ae merged into master
Platform: linux2

• python2.7: OK
• python3.2: OK (libraries not available: matplotlib pymongo wx wx.aui)

Not available for testing: python2.6, python3.1

[takluyver]

Looks good to me, but I'll let someone else have a quick glance over it (ping @fperez, @ellisonbg, @minrk)

[fperez]

Is this really the right description? If the validation attempts to compile, why is the trait itself called 'compiled'? I'm a little confused.

[bfroehle]

I suppose it should have the word "coerced" in there? That's why there is the C prefix, to be consistent with other traits.

[fperez]

I guess what it needs is a more complete docstring: regexps lingo is often ambiguous, because people often use the word 'regex' to describe either the pattern (which is a plain string) or the compiled regex (which is a very different object from a string). So I'd like the dosctring here to unambigously and explicitly indicate what it refers to, what it validates, what the constructor takes, etc. In other traits we don't need as much info b/c everybody has a reasonable idea of what an Int should be. But I think regexes deserve special consideration to avoid confusion in the future.

[minrk]

This accepts either a compiled expression or a string, but the attribute will always be a compiled regular expression object (re.compile(re.compile(pat)) is allowed). Adding 'casting' to the description would be appropriate.

[bfroehle]

A casting compiled regular expression trait.

Accepts both strings and compiled regular expressions. The resulting
attribute will be a compiled regular expression.

[minrk]

very clear, thanks!

[fperez]

yes, that's perfect, thanks!

[bfroehle]

Now with the improved docstring.