Esrap-PEG is a thin wrapper on top of Esrap that uses Esrap to parse PEG grammars and can use the resulting AST to define rules for an Esrap parser that parses the PEG grammar in question. See http://pdos.csail.mit.edu/~baford/packrat/popl04/peg-popl04.pdf and http://pdos.csail.mit.edu/~baford/packrat/ for more information. I use the canonical PEG definition with two exceptions. First, I allow octal escape \377 (original article says [0-2] for the first digit for some reason). Second, I allow \u followed by 4 hexadecimal digits for full Unicode escape. The library provides means to parse PEG syntax, to define rules in run-time without compiling any closures and to generate code that implements the rules in compiled module. It does a walk around the tree to define rules or to return code defining the rules. This parser uses the same permissive license as Esrap. Licence: Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.