any macro-like construct/technique/trick?

[Kay Schluehr]

Kay Schluehr wrote:
> Mac wrote:
> > Is there a way to mimic the behaviour of C/C++'s preprocessor for
> > macros?  The problem: a lot of code like this:
> >
> > def foo():
> >     # .... do some stuff
> >     if debug:
> >         emit_dbg_obj(DbgObjFoo(a,b,c))
> >
> >     # .... do more stuff
> >     if debug:
> >         emit_dbg_obj(DbgObjBar(d,e))
> >
> >     # ... and so on ...
> >
> > Notes:
> >
> > * the two-lines of debug conditional tend to really break up the flow
> > of the surrounding code
> >
> > * in C you could wrap them with a macro so you could do
> > DEBUG_EMIT(DbgObjFoo(a,b,c)), etc, with the macro only instantiating
> > the object and processing it if the debug flag was set.  The one-liner
> > is MUCH less disruptive visually when reading code
>
> Make emit_dbg_obj() a class to create one-liners:
>
> class Emit_dbg_obj:
>     debug = True
>     def __init__(self, algo):
>         self.algo = algo
>
>     def call_if_debug(self):
>         if self.debug:
>             return self.algo
>
> def foo2():
>     # .... do some stuff
>     Emit_dbg_obj(DbgObjFoo(a,b,c)).call_if_debug()
>
>     # .... do more stuff
>     Emit_dbg_obj(DbgObjFoo(c,d)).call_if_debug()
>
>
> Ciao,
> Kay

Hmmm... this won't work as expected.

class Emit_dbg_obj:
    debug = True
    def __init__(self, algo, args):
        self.algo = algo
        self.args = args


    def call_if_debug(self):
        if self.debug:
            self.algo(*self.args)

def foo2():
    # .... do some stuff
    Emit_dbg_obj(DbgObjFoo,(a,b,c)).call_if_debug()

    # .... do more stuff
    Emit_dbg_obj(DbgObjFoo,(c,d)).call_if_debug()


Regards,
Kay