i have a line of code which doesn’t work as i expect it too: parentspermission x y = if x && y == False then print(“no”) else print (“yes”) when i run parentspermission False False in ghci it gives me “yes” instead of “no” as it should be when false && false is false this may not be worth mention…

Check the precedences of (&&) and (==). Neither function is magical in the language.

a little addition is that when i ran parentspermission True False i got “no” as expected but when i ran parentspermission False True i somehow got “yes”

my understanding of this is the order i place && and ==, i would have usually placed a singlar equal sign after x && y but this isnt possible as a single equal sign is used to define functions.

The fix was to put x && y in parenthesis like so, (x && y) == False.

Noting that you are new to Haskell, you do not need ( ) around the "no" and "yes" values. To apply a function f :: a -> b to x :: a, you write f x. Accordingly, you can write print "no". Also, here, if you want Haskell code to be presented nicely, you can put it between ‘fences’ (each on their own …

I’d also add to this that I’d probably usually write if not (x && y) then ... else ... instead of (x && y) == False in the conditional. Edit: Also, welcome to Haskell :slight_smile:

Building on @slow-dive 's suggestion, there is a helpful (non-AI) tool named hlint: hlint: Source code suggestions which can help you learn by thinking through its suggestions. For example, if you put your code in a module: module MyModule ( parentspermission ) where parentspermission :: B…

A thing i would like to add although this may be a late response is that i started learning haskell via the learn you haskell for a great good website, but recently ive started reading real world haskell published by oreilly and i can say it is much better as it goes into much more depth

Where are you reading it? It seems the old https://book.realworldhaskell.org/ is dead.

You either purchase the book or use the ebook which is what im doing, i think this is an early version no one was supposed to get hands on but ive got it, just search up real world haskell in goole chrome and a link by red bean software will have a pdf called rwhdraft

Line of code not working as expected

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jaror July 26, 2026, 4:06pm 17

I’ve actually now gone and converted everything to markdown and started updating it. Maybe that is easier for you to read: