domain

From the SETL Wiki

domain
Category	map
Syntax	prefix
Compatibility
CIMS SETL	yes
SETL-S	yes
SETL2	yes
GNU SETL	yes

Contents 1 Purpose 2 Synopsis 3 Description 4 Examples 5 Notes

Purpose

Get the set of all keys in a map

Synopsis

 domain m

Description

Returns the set of keys occurring in m, which must be a map.

Equivalent to {k: [k, v] in m}

Examples

1. domain {}
   

   Result: {}

2. domain {[1, 10], [1, 11], [2, 20]}
   

   Result: {1, 2}

3. (SETL2 only)

   domain({[1, 10], [1, 11], [2]})
   

   Result: {1, 2}, though m(2) = om.

Notes

• This is one of few prefix operators in SETL2. Most prefix operators from SETL are implemented as built-in procedures in SETL2.