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.)

How do I run a program in GHCi?

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.)

How do I run GHCi in terminal?

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.

How do you write multiple lines in GHCi?

Update. As an alternative you can turn on multi-line input mode with :set +m , then type let on its own, hit Enter, then paste definitions with no indentation required.

Is GHCi interpreted?

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.

How do I run a Visual Studio code in Haskell?

Features. Press command + shift + P to: Load GHCi(or Stack/Cabal repl) with current file: Load GHCi. Run current Haskell file: Run Haskell File.

What is stack ghci?

stack ghci allows you to load components and files of your project into ghci . It uses the same TARGET syntax as stack build , and can also take options like –test , –bench , and –flag . Similarly to stack build , the default is to load up ghci with all libraries and executables in the project.

How do I use let in Haskell?

The keyword let is used in three ways in Haskell.

1. The first form is a let-expression. let variable = expression in expression.
2. The second is a let-statement. This form is only used inside of do-notation, and does not use in .
3. The third is similar to number 2 and is used inside of list comprehensions. Again, no in .

Is Haskell based on C?

The Glasgow Haskell Compiler supports an extended type system based on the theoretical System FC. Major extensions to the type system include: Arbitrary-rank and impredicative polymorphism.