#lang scribble/manual

@title{if}

If statements in Pyret look very similar to if statements in Python.

@verbatim|{
fun sgn(x):
  if x < 0: -1
  elif x = 0: 0
  else: 1
}|

If statements can only have one expression after the colon. Nested if
statements require a newline, and follow the SLGC indent rule.

Else statements are not required, but when not using one, the
@tt[]{:done} keyword is required to let Pyret know that you have
finished the if statement.

@verbatim|{
fun sgn(x):
  if x < 0: -1
  elif x = 0: 0
  elif x > 0: 1
  :done
}|

Pyret will signal an error if you fall through the if statement.