pgpg-experiments

This is a template package for experimenting with the Pretty Good Parser Generator. One Go module at the repo root depends on github.com/johnkerl/pgpg/go; each subdirectory is a separate example app.

Build

From the repo root:

go  build -o ast-print/ast-print      ./ast-print
go  build -o json-stream/json-stream  ./json-stream
go  build -o pascal-s/pascal-s        ./pascal-s
go  build -o pemdas-eval-gen/tryparse ./pemdas-eval-gen

See each subdirectory's README.md for how to run and regenerate.

Updating the pgpg dependency

When new versions of PGPG are tagged (e.g. go/v0.2.0), from the repo root:

go get github.com/johnkerl/pgpg/go@v0.2.0
go mod tidy

Using one app as a template

To start your own project from one of these apps: copy the app directory (e.g. pemdas-eval-gen/) into a new repo, add a go.mod at the root with module your-module-name-goes-here, and require github.com/johnkerl/pgpg/go v0.1.0 (or the latest version). Then change that app's imports from github.com/johnkerl/pgpg-experiments/... to <your-module>/generated/... so the single main package builds under your module.

Co-developing with PGPG

To work on pgpg-experiments and pgpg in parallel (e.g. developing/tweaking the pgpg library while testing in these apps), use a go.work file so the Go toolchain uses your local pgpg checkout instead of the published module.

1. Clone both repos as siblings:

   git clone https://github.com/johnkerl/pgpg
   git clone https://github.com/johnkerl/pgpg-experiments
   

   so you have pgpg/ and pgpg-experiments/ next to each other.

2. Create go.work in the pgpg-experiments root:

   cd pgpg-experiments
   go work init .
   go work use ../pgpg/go
   

   Or create it manually:

   go 1.25
   
   use (
       .
       ../pgpg/go
   )
   

3. Build and run as usual. The workspace makes go build and go test use your local pgpg code.

4. Do not check go.work or go.work.sum in to source control. It's listed in .gitignore. Each developer creates their own when needed.

5. To switch back to the published module, remove or rename go.work. To temporarily suppress, export GOWORK=off for your current terminal session.