On Wednesday, 15 February 2017 22:33:42 GMT Chris Angelico wrote:
> On Wed, Feb 15, 2017 at 10:18 PM, Steven D'Aprano <st...@pearwood.info>
wrote:
> > Python doesn't have thunks, but there is a relatively heavyweight
> > solution for delayed evaluation: wrap the code in a function.
> >
> > debugLog( ‘info is %r’, lambda: expensiveFunction() )
> >
> >
> > and then adjust debugLog so that if the argument is a function, it will
> > call the function only when needed:
> >
> > def debugLog(message, value):
> > if debug_log_enabled:
> > if isinstance(value, types.FunctionType):
> > value = value()
> >
> > log(message % value)
>
> Or use the function as the __repr__ of some object, which comes to the
> same thing without requiring special code inside debugLog.
__repr__ is interesting however.
Typically I describe in a string why the value is being logged. That means
that the object is always a string. I cannot recall using debugLog( obj )
in production.
dlog('This is the state of obj at the start of event processing: %r' % (obj,))
Barry
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