Install requisites:

• chezscheme - you should have the scheme command available in your $PATH.
• libpcre2 - purescm has a runtime dependency on the 16-bit variant of pcre2. Check your package manager for pcre2 or pcre2-16 or similar.
• icu - libicu is used for locale-aware case conversions.

You can install purescm with npm:

npm i --global purescm 

The best way to use purescm is to use the spago integration for alternative PureScript backends. In spago.yaml use the backend config like so:

workspace: backend: cmd: purescm args: - "build" 

Then to compile your purescm project you can run:

spago build 

This will produce output under output/. You can run the compiled program with:

purescm run 

Scheme files can be precompiled to a single Chez program:

purescm bundle-app 

which generates a single file output/main which can be run with scheme or petite:

scheme --program output/main 

To run all tests, run npm run test. This will run both the scheme runtime unit tests and the snapshot tests.

To overwrite old snapshots with the latest output, run npm run test -- -a "--accept". To add a new snapshot, create a file called Snapshot.X.purs where X indicates what is being tested. If a snapshot needs a dependency, install it by running cd test-snapshots && spago install <packages...>.

In order to represent Array and record types in purescm, the backend has a runtime dependency on implementation of SRFI 214 (Flexvectors). This is due in part to how vectors are more like "arrays" than "array lists".

We vendor chez-srfi using the following steps:

1. Clone chez-srfi at the project root.

2. Navigate to chez-srfi and run ./install.chezscheme.sps ../lib.

3. To verify, simply invoke the Scheme REPL:

$ scheme --libdirs ./lib: Chez Scheme Version 9.5.8 Copyright 1984-2022 Cisco Systems, Inc. > (import (srfi :125)) >