26.3 Predicates

Function: char-set? obj

Return #t if obj is an object of type char-set, else return #f.

Function: char-set?/internals obj

Return #t if obj is an object of type char-set and its internal representation is valid; otherwise return #f. This function is more time–consuming than char-set?, and it is meant for debugging purposes.

Function: char-set-empty? cs

Return #t if the char-set is empty, else return #f.

Function: char-set-contains? cs char

Return #t if char is an element of cs.

Function: char-set=? cs …

Return #t if the arguments represent the same char-set, else return #f. When called with no arguments: return #t. When called with one argument: return #t.

Function: char-set<? cs …

Return #t if all the elements of cs are strictly less than all the elements of the subsequent cs, else return #f. Empty sets cannot be ordered, so if an argument is empty the return value is #f. When called with no arguments: return #t. When called with one argument: return #t.

Function: char-set<=? cs …

Return #t if all the elements of cs are non–strictly less than all the elements of the subsequent cs, else return #f. Empty sets cannot be ordered, so if an argument is empty the return value is #f. When called with no arguments: return #t. When called with one argument: return #t.

Function: char-set-subset? cs ...

Function: char-set-subset?/strict cs ...

Return #t if the arguments, in the given order, are subsets of each other or strict subsets of each other, else return #f. When called with zero or one argument: return #t.

Function: char-set-superset? cs ...

Function: char-set-superset?/strict cs ...

Return #t if the arguments, in the given order, are supersets of each other or strict supersets of each other, else return #f. When called with zero or one argument: return #t.