README.md · rowtype-yoga/purescm

git.iko.soy/rowtype-yoga/purescm

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1# purescm - Chez Scheme backend for PureScript

3## Installation

5Install requisites:

7* [`chezscheme`](https://cisco.github.io/ChezScheme/) - you should have the `scheme` command available in your `$PATH`.

8* [`libpcre2`](https://pcre2project.github.io/pcre2/) - `purescm` has a runtime dependency on the 16-bit variant of pcre2. Check your package manager for `pcre2` or `pcre2-16` or similar.

9* [`icu`](https://icu.unicode.org/) - `libicu` is used for locale-aware case conversions.

11You can install purescm with npm:

13```

14npm i --global purescm

15```

17## Usage

19The best way to use `purescm` is to use the [spago](https://github.com/purescript/spago) integration for alternative PureScript backends. In `spago.yaml` use the `backend` config like so:

21```

22workspace:

23 backend:

24 cmd: purescm

25 args:

26 - "build"

27```

29Then to compile your `purescm` project you can run:

31```

32spago build

33```

35This will produce output under `output/`. You can run the compiled program with:

37```

38purescm run

39```

41### Bundling

43Scheme files can be precompiled to a single Chez program:

45```

46purescm bundle-app

47```

49which generates a single file `output/main` which can be run with `scheme` or `petite`:

51```

52scheme --program output/main

53```

55## Development

57### Running the tests

59To run all tests, run `npm run test`. This will run both the scheme runtime unit tests and the snapshot tests.

61To overwrite old snapshots with the latest output, run `npm run test -- -a "--accept"`.

62To add a new snapshot, create a file called `Snapshot.X.purs` where `X` indicates what is being tested.

63If a snapshot needs a dependency, install it by running `cd test-snapshots && spago install <packages...>`.

65### Vendored Dependencies

67In 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](https://cisco.github.io/ChezScheme/csug9.5/objects.html#./objects:h5) are more like "arrays" than "array lists".

69We vendor [chez-srfi](https://github.com/arcfide/chez-srfi) using the following steps:

711. Clone `chez-srfi` at the project root.

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

753. To verify, simply invoke the Scheme REPL:

76```scheme

77$ scheme --libdirs ./lib:

78Chez Scheme Version 9.5.8

81> (import (srfi :125))

82>

83```