what is lambda used for in real code?

[Steven Bethard]

I wrote:
> * Functions I don't know how to rewrite
> Some functions I looked at, I couldn't figure out a way to rewrite them 
> without introducing a new name or adding new statements.
> 
[snip]
>
> inspect.py: def formatargspec(args, varargs=None, varkw=None,
>                   ...
>                   formatvarargs=lambda name: '*' + name,
>                   formatvarkw=lambda name: '**' + name,
>                   formatvalue=lambda value: '=' + repr(value),
> inspect.py: def formatargvalues(args, varargs, varkw, locals,
>                     ...
>                     formatvarargs=lambda name: '*' + name,
>                     formatvarkw=lambda name: '**' + name,
>                     formatvalue=lambda value: '=' + repr(value),

Realized today that I do know how to rewrite these without a lambda, 
using bound methods:
     def formatargspec(args, varargs=None, varkw=None,
                       ...
                       formatvarargs='*%s'.__mod__,
                       formatvarkw='**%s'.__mod__,
                       formatvalue='=%r'.__mod__,
I like this rewrite a lot because you can see that the function is 
basically just the given format string. YMMV, of course.

Similarly, if DEF_PARAM, DEF_BOUND and glob are all ints (or supply the 
int methods), I can rewrite

> symtable.py:       self.__params = self.__idents_matching(lambda x:
>                                                           x & DEF_PARAM)
> symtable.py:       self.__locals = self.__idents_matching(lambda x:
>                                                           x & DEF_BOUND)
> symtable.py:       self.__globals = self.__idents_matching(lambda x:
>                                                            x & glob)

with the bound methods of the int objects:
     self.__params = self.__idents_matching(DEF_PARAM.__rand__)
     self.__locals = self.__idents_matching(DEF_BOUND.__rand__)
     self.__globals = self.__idents_matching(glob.__rand__)
(Actually, I could probably use __and__ instead of __rand__, but 
__rand__ was the most direct translation.)


Ahh, the glory of bound methods... ;)

Steve