https://github.com/lyokha/ghc-stdin

A frontend plugin for GHC to compile source code from the standard input
https://github.com/lyokha/ghc-stdin

frontend ghc haskell plugin

Last synced: 26 days ago
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A frontend plugin for GHC to compile source code from the standard input

• Host: GitHub
• URL: https://github.com/lyokha/ghc-stdin
• Owner: lyokha
• License: bsd-3-clause
• Created: 2022-08-03T15:55:38.000Z (over 2 years ago)
• Default Branch: master
• Last Pushed: 2023-11-29T20:29:07.000Z (11 months ago)
• Last Synced: 2024-09-30T09:04:02.045Z (about 1 month ago)
• Topics: frontend, ghc, haskell, plugin
• Language: Haskell
• Homepage:
• Size: 15.6 KB
• Stars: 6
• Watchers: 2
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • Changelog: Changelog.md
  • License: LICENSE

Awesome Lists containing this project

README

        
GHC frontend plugin GhcStdin

============================

[![Build Status](https://github.com/lyokha/ghc-stdin/workflows/CI/badge.svg)](https://github.com/lyokha/ghc-stdin/actions?query=workflow%3ACI)

[![Hackage](https://img.shields.io/hackage/v/ghc-stdin.svg?label=hackage%20%7C%20ghc-stdin&logo=haskell&logoColor=%239580D1)](https://hackage.haskell.org/package/ghc-stdin)

In GHC, it is not possible to read source code from the standard input.

```ShellSession

$ echo 'module Main where main = putStrLn "Ok"' | ghc -o simple_ok

ghc-9.2.3: no input files

Usage: For basic information, try the `--help' option.

```

This plugin makes this possible.

```ShellSession

$ echo 'module Main where main = putStrLn "Ok"' | ghc --frontend GhcStdin -ffrontend-opt="-o simple_ok"

[1 of 1] Compiling Main             ( ghc-stdin-d8c31cf0ed893d79/ghc-stdin260612-0.hs, ghc-stdin-d8c31cf0ed893d79/ghc-stdin260612-0.o )

Linking simple_ok ...

$ ./simple_ok

Ok

```

Notice that GHC flags are passed via *-ffrontend-opt* in a single string.

Another use case is collecting exported FFI C functions from a module and

putting them in a new shared library.

```ShellSession

$ export NGX_MODULE_PATH=/var/lib/nginx/x86_64-linux-ghc-$(ghc --numeric-version)

$ echo 'module NgxHealthcheck where import NgxExport.Healthcheck ()' | ghc --frontend GhcStdin -ffrontend-opt="-Wall -O2 -dynamic -shared -fPIC -flink-rts -threaded -L$NGX_MODULE_PATH -lngx_healthcheck_plugin -o ngx_healthcheck.so" 

[1 of 1] Compiling NgxHealthcheck   ( ghc-stdin-74de48274545714b/ghc-stdin266454-0.hs, ghc-stdin-74de48274545714b/ghc-stdin266454-0.o )

Linking ngx_healthcheck.so ...

```

(this is a real-world example taken from

[nginx-healthcheck-plugin](https://github.com/lyokha/nginx-healthcheck-plugin)).

Internally, the plugin creates a temporary directory with a temporary source

file inside it with the contents read from the standard input. Then it spawns

another GHC process to compile this file with the options passed in

*-ffrontend-opt*.