On Saturday, July 30, 2016 at 10:45:23 PM UTC+5:30, Chris Angelico wrote: > On Sun, Jul 31, 2016 at 2:58 AM, Rustom Mody wrote: > >> Where, in any useful production code, is the difference between > >> functions and procedures actually helpful? Or where, in student code, > >> would it be useful to distinguish? I've been teaching Python to > >> students with a variety of backgrounds, and nobody has yet been > >> bothered by this. Not a single one. > >> > >> ChrisA > > > > In English — and all Indo-European¹ languages — there are two moods > > “It is raining” is in declarative mood > > “Come in!” is in imperative mood > > > > Now there is a realm in which they are not distinct > > > > “It is raining!” said Harry Potter to Hermione and it started raining > > “Come in!” said Harry, And the chair walked hoppety-hop into the room > > > > So sure if you want to teach magic to your kids, all power to you. > > Myself, I’ll stick to what I know better than magic — programming > > Answer the question, maybe... when *in programming* is this > distinction important?
eg 1 We can write am assignment in a loop Can we write a loop in an assignment like? x = while x ... Less interesting answer — No we cannot More pertinent — In our zany new language we are inventing we are going to allow this. Ok... What will it mean? eg 2 A function can - return a constant - a variable - more generally an expression How about returning a while loop? In short you use the imperative-declarative distinction every day all the time every line of code that you write. Some languages reify that as an expression/statement function/procedure division — Pascal. But even if your language does not support that reification you would not be able to write a single line of correct code without it. Broadly (and simplistically): - When you ask a question — condition of if or while — you need a declarative entity - When you do an action — assignment, body of if/loop — you need an imperative entity -- https://mail.python.org/mailman/listinfo/python-list
