Copyright | (c) Alexey Radkov 2022 |
---|---|
License | BSD-style |
Maintainer | alexey.radkov@gmail.com |
Stability | experimental |
Portability | non-portable (requires GHC with support of plugins) |
Safe Haskell | None |
Language | Haskell2010 |
A frontend plugin for GHC to compile source code from the standard input.
Synopsis
Documentation
frontendPlugin :: FrontendPlugin Source #
Frontend plugin for GHC to compile source code from the standard input.
In GHC, it is not possible to read source code from the standard input.
$ 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.
$ 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.
$ export NGX_MODULE_PATH=/var/lib/nginx/x86_64-linux-ghc-9.2.3 $ echo 'module NgxHealthcheck where import NgxExport.Healthcheck ()' | ghc --frontend GhcStdin -ffrontend-opt="-Wall -O2 -dynamic -shared -fPIC -lHSrts_thr-ghc$(ghc --numeric-version) -L$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).
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 options passed in -ffrontend-opt.