#Shorter syntax for lists of lists and a way to declare maps

You can save bytes on lists of lists. If you have a list [[1,2],[3,4]], you can actually declare it as [1:2,3:4], which saves 4 brackets = 4 bytes. Note that you can use something else than : (for example, ^).

1:2 isn't actually a list in that case (whereas [1,2] was), it is represented internally as :(1,2). Therefore you cannot use predicates that work on lists on those sublists that use colons.

This trick is mainly used to declare maps, i.e. a list of keys with values attached to them. For example, if you want to declare a map M that contains the spelling of a digit in both English and French, you could do something like this:

M=[0:'Zero':'Zéro',1:'One':'Un',2:'Two':'Deux', ... ] 

You can then for example retrieve elements of the map with a built-in predicate like member/2. For example, if you want the digit and English word corresponding to 'Quatre' in M, you could do:

member(Digit:Name:'Quatre',M). 

Shorter syntax for lists of lists and a way to declare maps

You can save bytes on lists of lists. If you have a list [[1,2],[3,4]], you can actually declare it as [1:2,3:4], which saves 4 brackets = 4 bytes. Note that you can use something else than : (for example, ^).

1:2 isn't actually a list in that case (whereas [1,2] was), it is represented internally as :(1,2). Therefore you cannot use predicates that work on lists on those sublists that use colons.

This trick is mainly used to declare maps, i.e. a list of keys with values attached to them. For example, if you want to declare a map M that contains the spelling of a digit in both English and French, you could do something like this:

M=[0:'Zero':'Zéro',1:'One':'Un',2:'Two':'Deux', ... ] 

You can then for example retrieve elements of the map with a built-in predicate like member/2. For example, if you want the digit and English word corresponding to 'Quatre' in M, you could do:

member(Digit:Name:'Quatre',M).