laindir / re

Proof of concept regex to teach myself syntax trees

This is a proof of concept regex compiler/executor. It should NOT be used in production. It does not adhere to any particular standard and is guaranteed to have severe shortcomings.

#Regular Expressions

Regular expressions are a syntax for describing regular languages. These are languages that can be parsed without any look ahead. The following elements are available:

##literal

Any character that does not have a special meaning matches itself.

##.

The dot matches any character.

##* The star operatior indicates that the preceding subexpression may be repeated zero or more times to be matched by the star.

##( and ) Parentheses group tokens into a subexpression.

##{x,y} ###Not Implemented Braces escaped with a backslash indicate that the preceding subexpression may be repeated at least x times but not more than y times. If y is omitted, the subexpression may be matched x or more times. If y and the comma are omitted, the subexpression must be matched exactly x times.

##| The pipe stands for alternation between two subexpressions. If either subexpression matches, their alternation also matches.