The LaTeX3 package pegmatch

Caption     : Parsing Expression Grammars for TeX
Author      : Jianrui Lyu <tolvjr@163.com>
CTAN Page   : https://ctan.org/pkg/pegmatch
Repository  : https://github.com/lvjr/pegmatch
License     : The LaTeX Project Public License 1.3c

The pegmatch package ports PEG (Parsing Expression Grammars) to TeX. Following the design in LPEG (Parsing Expression Grammars for Lua), it defines patterns as LaTeX3 variables, and offers several operators to compose patterns. In general, PEG matching is much more powerful than RE (Regular Expressions) matching. At this time, pegmatch package only supports TeX strings. Also it is still in experimental status, hence some interfaces may change in future releases.