Editing Pattern matching (section)

====Example string patterns====
In Mathematica, for instance,
<syntaxhighlight lang="mathematica">
StringExpression["a",_]
</syntaxhighlight>
will match a string that has two characters and begins with "a".

The same pattern in Haskell:

<syntaxhighlight lang="haskell">
['a', _]
</syntaxhighlight>

Symbolic entities can be introduced to represent many different classes of relevant features of a string. For instance,

 StringExpression[LetterCharacter, DigitCharacter]

will match a string that consists of a letter first, and then a number.

In Haskell, [[Guard (computer science)|guards]] could be used to achieve the same matches:

<syntaxhighlight lang="haskell">
[letter, digit] | isAlpha letter && isDigit digit
</syntaxhighlight>

The main advantage of symbolic string manipulation is that it can be completely integrated with the rest of the programming language, rather than being a separate, special purpose subunit. The entire power of the language can be leveraged to build up the patterns themselves or analyze and transform the programs that contain them.