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Is there a way to determine the type of an element within a list in Prolog? I know that variables aren’t explicitly typed in Prolog, but I need to check whether an element is a number, a specific character, etc. How can this be accomplished?
Prolog defines a group of built-in predicates for type testing purposes:
var/1,atom/1,integer/1,float/1,atomic/1,compound/1,nonvar/1,number/1, all of them with quite a self-explanatory meaning if you know the data types of the language. For specific characters, you may exploit unification with that character, after checking that the element is not a free variable (otherwise unification is always successful).