To add comments in Haskell, we use the ‘--’ symbol. This symbol tells the compiler to ignore everything that follows on that line. Here is an example:
-- This is a comment in Haskell
main :: IO ()
main = do
putStrLn "Hello World!" -- This is also a comment
In this example, we have two comments. The first comment is on its own line and the second comment is after a line of code. Both comments use the ‘--’ symbol. When the compiler encounters this symbol, it ignores everything that follows on that line.
Note that we can also use multi-line comments in Haskell by enclosing them in ‘{-’ and ‘-}’ symbols. Here is an example:
{- This is
a multi-line
comment in Haskell -}
main :: IO ()
main = do
putStrLn "Hello World!" {- This is also a comment -}
In this example, we have a multi-line comment. The comment starts with ‘{-’ and ends with ‘-}’. Everything in between these symbols is ignored by the compiler. We also have another comment after a line of code, and it’s enclosed in ‘{-’ and ‘-}’ symbols.