On Jan 18, 6:07 pm, "Gabriel Genellina" <gagsl-...@yahoo.com.ar> wrote: > En Mon, 18 Jan 2010 19:00:17 -0300, Steve Howell <showel...@yahoo.com> > escribió: > > > Hi, I have a style/design question relating to recursion and inner > > methods. > > > I wrote some code recently that implements a recursive algorithm that > > takes several parameters from the original caller. Once the algorithm > > starts running and recursing, those parameters remain the same, so I > > define an inner method called "recurse" that essentially curries those > > parameters. In particular, the recurse method can get passed to a > > callback method that the caller supplies, so that the caller can wrap > > the recursive step with their own logic. > > Python already have lexical scoping, you can take advantage of it. On any > non-prehistoric version of Python you may write: > > def indent_lines(lines, > branch_method, > leaf_method, > pass_syntax, > flush_left_syntax, > flush_left_empty_line, > indentation_method, > get_block, > ): > > def _indent_lines(lines): > output = [] > while lines: > # ... the real work ... > # recursive call: > output += branch_method(prefix, block, _indent_lines) > return output > > return _indent_lines(lines) > > The real work happens inside _indent_lines, and it has access to the outer > indent_lines scope, where all remaining parameters are defined. > > > The only thing I don't like about the technique that I'm using is that > > it seems needlessly repetitive to define mostly the same parameter > > list in two different places. The repetition seems mostly harmless, > > but it seems like some kind of a smell that I'm overlooking a simpler > > way to write the code. I just can't put my finger on what it is. > > Is the above technique what you were looking for? >
That was exactly what I was looking for. I just tried it out, and it works perfectly. Thanks! -- http://mail.python.org/mailman/listinfo/python-list
