Optional arguments: General case

Work In Progress

This page is a draft

OK so we now know how to have a few optional arguments with a default value, but what if we want to do something entierly different depending on the number of arguments provided ?

Objective

A range macro similar to the python builtin function, that allows one to iterate over a range of integers:

• range(STOP) iterates from 0 to STOP, STOP excluded

• range(START, STOP) iterates from START to STOP, STOP excluded

• range(START, STOP, STEP) iterates from START to STOP by steps of STEP, STOP excluded

Examples:

• range(5): 0 1 2 3 4

• range(3, 8): 3 4 5 6 7

• range(2, 7, 3): 2 5

How will it look like in C ? Well it’s up to you, here are a few propositions:

Syntax 1

Indented correctly by you text editor by default

for (int in_range(i, 5))
	/* 0 1 2 3 4 */;
for (int in_range(i, 3, 8))
	/* 3 4 5 6 7 */;
for (int in_range(i, 2, 7, 3))
	/* 2 5 */;

Syntax 2

Single parenthesis level

for_in_range(int, i, 5)
	/* 0 1 2 3 4 */;
for_in_range(int, i, 3, 8)
	/* 3 4 5 6 7 */;
for_in_range(int, i, 2, 7, 3)
	/* 2 5 */;

Syntax 3

Explicit variable declaration

int i;
for_in_range(i, 5)
	/* 0 1 2 3 4 */;
for_in_range(i, 3, 8)
	/* 3 4 5 6 7 */;
for_in_range(i, 2, 7, 3)
	/* 2 5 */;