@Οurous I'm not sure if the alternatives for and and or can be used to save bytes, because they are longer than import StdEnv. But anyway I think it is kind of fun to reimplement as much of StdEnv as possible with only the core language feaures.
Reminds me of this CnR answer in Haskell, where all the Prelude functions are inaccessible.
?[True:t]= ?t;?_=False always returns False, but %[a:r]|a= %r=a;%_=True works for the same byte count.
Know how to learn the language
After all, how can anyone golf in a language they can't use!
Online
Clean isn't a well-known or well-documented language, and the name certainly doesn't make it easy to find much-needed resources to remedy these issues... or does it?
Clean was originally called ...
Forget about character encoding
Clean's compiler doesn't care about what encoding you think you've saved the source file as, just about the byte values in the file. This has some neat consequences.
In the body of the source code, only bytes with code-points corresponding to the printable ASCII ...
Know your Knodes
Some of the strongest constructs (for golfing) in functional languages are let ... in ....
Clean of course, has this, and something better - the #.
What is a node?
Clean's #, and the ubiquitous | (pattern guard) are both known as 'node expressions'. They represent specific nod...
Avoid import StdEnv when possible
To access built-in functions, even seemingly basic ones like (==) or map, an import statement is needed, usually import StdEnv because it imports the most common modules like StdInt, StdBool and so on (see here for more info on StdEnv).
However it can be possib...
Use shorter lambdas
Sometimes you find yourself using a lambda expression (to pass to map, or sortBy, etc.). When you're doing this (writing lambdas), there's the right... and the short way.
The right way:
This is sortBy, with an idiomatic lambda sorting lists from longest to shortest
sortBy ...
@Laikoni do you know of a shorter way to clear output than using StdIO with a GUI? I seem to remember finding something with System._Unsafe and using OS commands but I can't find it.