4. Using runghc¶
runhaskell, which is its equivalent) allows you to run Haskell programs using the interpreter, instead of having to
compile them first.
runghc command-line looks like:
runghc [runghc flags] [GHC flags] module [program args]
Any flags not recognized by runghc are automatically passed to GHC.
If a flag is recognized by both runghc and GHC but you want to
pass it to GHC then you can place it after a
-- separator. Flags after the
separator are treated as GHC only flags. Alternatively you can use the runghc
--ghc-arg=<arg> to pass any flag or argument directly to GHC.
module could be a Haskell source filename with or without the extension.
If for some reason the filename starts with a
- you can use a second
-- to indicate the end of flags. Anything following a second
-- will be considered a program file or module name followed by its
arguments. For example:
runghc -- -- -hello.hs
4.2. runghc flags¶
runghc accepts the following flags:
-f /path/to/ghc: tell runghc the path of GHC executable to use to run the program. By default runghc will search for GHC in the directories in the system search path.
--ghc-arg=<arg>: Pass an option or argument to GHC
--help: print usage information.
--version: print version information.
4.3. GHC Flags¶
As discussed earlier, use
--ghc-arg=<arg> to disambiguate GHC
flags when needed. For example,
-f is recognized by runghc, therefore to
-fliberate-case to GHC use any of the following:
runghc -- -fliberate-case
Note that any non-flag arguments are never passed to GHC. An unused non-flag
argument will be considered as the name of the program to run. If a GHC flag
takes an argument use
--ghc-arg=<arg> to pass the argument to GHC.
For example, if you want to pass
-package foo to GHC use any of the
runghc -package --ghc-arg=foo Main.hs
runghc --ghc-arg=-package --ghc-arg=foo Main.hs