Margaret - Janet's peg/match in Janet

This aims to be a pure-Janet implementation of Janet's peg/match.

Apart from having fun, here are some reasons why this could be of some interest.

Setup

• Clone this repository and cd to the relevant directory

• Ensure janet and jpm are on your PATH

• Install if you like: jpm install

Usage

Basic Use

meg/match is an attempt at implementing peg/match, so for example, if margaret has already been installed:

(import margaret/meg)

(meg/match ~(capture (some "smile")) "smile!")

should work.

Tracing

There is some primitive support for tracing. It can be enabled by setting the VERBOSE environment variable to a non-empty string.

Either:

• set the VERBOSE env var (say to "1") before starting janet, or
• use (os/setenv "VERBOSE" "1") in code

before calling meg/match.

Output format is very much in-flux but ATM one can see:

• capture stack
• tags
• specials execution order

...and other details.

See here for more.

Users

• janet-pegdoc reuses examples from margaret to show sample invocations of peg/match as well as a source for generating quizzes.

• small-peg-tracer uses the emulation and tracing capabilities of margaret while generating views of simulated peg/match execution.

Other Docs

• The Specials lists what's currently implemented
• Tutorials of a sort
• Testing details
• Implementation Notes for the curious
• Credits to acknowledge help