A Parsing Expression Grammar ( hence peg) is a way to create grammars similar in principle to regular expressions but which allow better code integration. Specifically, peg is an implementation of the Packrat parser generator originally implemented as peg/leg by Ian Piumarta in C. A Packrat parser is a "descent recursive parser" capable of backtracking and negative look-ahead assertions which are problematic for regular expression engines.

See peg-file-syntax.md for creating your own *.peg file.

1. Add peg as a tool dependency

   go get -tool github.com/pointlander/peg@main
   

2. Create your mygrammar.peg

3. Add a //go:generate line in a Go source of your package

   //go:generate go tool peg mygrammar.peg

   ---

   Widespread community design pattern: Add lines like this in doc.go.

4. Generate mygrammar.peg.go from mygrammar.peg

   go generate
   

This creates the file peg.peg.go

go tool peg -inline -switch peg.peg

go tool peg -h

• Golang, see go.mod for version
• golangci-lint latest version (v2 or later)
• Bash 3.2.x or higher

Bootstrap and generate grammar *.peg.go. This commands should initially be executed once before other commands.

go generate

go build

(go generate required once beforehand)

Use the version from the tag if the current commit has a tag. If not use the current commit hash.

go build -ldflags "-X main.Version=$(git describe --tags --exact-match 2>/dev/null || git rev-parse --short HEAD)"

Additionally, since Go 1.18 the go command embeds version control information. Read the information:

go version -m peg

go test -short ./...

(go generate required once beforehand)

golangci-lint run

(go generate required once beforehand)

golangci-lint fmt

go test -benchmem -bench .

(go generate required once beforehand)

Andrew Snodgrass