I've been told you can interpret Haskell files (which I assume means they will work like Ruby/Python/Perl). I can't find the command line option on GHC to do this, though. It always wants to compile my file. Took a look at GHCi as well, but it always dumps me into a repl.
I'm basically wanting to just do ghc -i MyFile.hs
(where -i is a made up flag that I'm pretending correllates to interpreted mode) and have it execute so that I can get quick feedback while I'm trying out ideas and learning.
If you have installed the Haskell Platform, open a terminal and type ghci (the name of the executable of the GHC interpreter) at the command prompt. Alternatively, if you are on Windows, you may choose WinGHCi in the Start menu. And you are presented with a prompt. The Haskell system now attentively awaits your input.
Open a command window and navigate to the directory where you want to keep your Haskell source files. Run Haskell by typing ghci or ghci MyFile. hs. (The "i" in "GHCi" stands for "interactive", as opposed to compiling and producing an executable file.)
GHCi interprets the whole line as an expression to evaluate. The expression may not span several lines - as soon as you press enter, GHCi will attempt to evaluate it. In Haskell, a let expression is followed by in .
GHCi is the interactive interface to GHC. From the command line, enter "ghci" (or "ghci -W") followed by an optional filename to load. Note: We recommend using "ghci -W", which tells GHC to output useful warning messages in more situations. These warnings help to avoid common programming errors.
$ runhaskell MyFile.hs
Alternatively, runghc
(they're the same thing). ghci MyFile.hs
will also start an interactive REPL session with MyFile.hs
loaded, but if you want to run a main program then runhaskell
is the way to go.
It's probably a good idea to get into the habit of testing parts of your program as isolated units in GHCi rather than running the whole thing each time, but obviously for shorter scripts it's simplest and easiest just to run the entire thing.
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