Functions vs OOP

rusi rustompmody at gmail.com
Sun Sep 4 15:13:58 CEST 2011


On Sep 3, 9:15 pm, William Gill <nore... at domain.invalid> wrote:
> During some recent research, and re-familiarization with Python, I came
> across documentation that suggests that programming using functions, and
> programming using objects were somehow opposing techniques.

Staying with (for the moment) the suggestion that OO-P and F-P are
complementary, I believe it is worthwhile to distinguish syntactic OO-
P vs F-P from semantic OO-P vs F-P.

Syntactically: f(x) is functional x.f() is object oriented.
Semantically if f's return value depends only on x ie does not depend
on state it is functional (in the math sense) -- the jargon is that f
is referentially transparent.

Referential opaqueness is usually such a source of problems that it
turns out good to contain the problem somewhat -- hence the wish for
encapsulation.

One can find in the python library itself all 4 combinations:
syntactically and semantically OO : sort
syntactically and semantically FP: sorted
syntactically OO semantically FP: join



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