4. Using runghc¶
runghc
allows you to run Haskell programs without first having to
compile them.
4.1. Usage¶
The 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
option --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 --
or --ghc-arg=<arg>
to disambiguate GHC
flags when needed. For example, -f
is recognized by runghc, therefore to
pass -fliberate-case
to GHC use any of the following:
runghc -- -fliberate-case
runghc --ghc-arg=-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
following:
runghc -package --ghc-arg=foo Main.hs
runghc --ghc-arg=-package --ghc-arg=foo Main.hs