Editing Pascal (programming language) (section)

===Set types===
In contrast with other programming languages from its time, Pascal supports a set type:<ref name="Mandell1987">{{cite book |first=Steven L. |last=Mandell |title=Pascal Programming Today |url=https://archive.org/details/turbopascalprogr00mand |url-access=registration |year=1987 |publisher=West Publishing Company |isbn=978-0-314-33935-5}}</ref>

:<syntaxhighlight lang="pascal">
var
    Set1 : set of 1..10;
    Set2 : set of 'a'..'z';
</syntaxhighlight>

A set is a fundamental concept for modern mathematics, and they may be used in many algorithms. Such a feature is useful and may be faster than an equivalent construct in a language that does not support sets. For example, for many Pascal compilers:

:<syntaxhighlight lang="pascal">
if i in [5..10] then ...
</syntaxhighlight>

executes faster than:

:<syntaxhighlight lang="pascal">
if (i > 4) and (i < 11) then ...
</syntaxhighlight>

Sets of non-contiguous values can be particularly useful, in terms of both performance and readability:

:<syntaxhighlight lang="pascal">
if i in [0..3, 7, 9, 12..15] then ...
</syntaxhighlight>

For these examples, which involve sets over small domains, the improved performance is usually achieved by the compiler representing set variables as [[bit vector]]s. The set [[Operator (programming)|operators]] can then be implemented efficiently as bitwise machine code operations.