Document lset.

doc/utils.md

@@ -68,6 +68,87 @@ predicate.
 
 ### Set (List)
 
+    (import util-set-list)
+
+This module implements linear-time set with custom comparator.
+
+    (make-lset [comparator])
+
+* ```comparator``` - comparison procedure, defaults to ```equal?```
+
+Creates new lset with given comparator.
+
+    (lset-empty? ls)
+
+* ```ls``` - lset instance
+
+Returns ```#t``` if given lset contains no elements.
+
+    (lset-member? ls el)
+
+* ```ls``` - lset instance
+* ```el``` - element to check
+
+Returns ```#t``` if given element ```el``` is contained in the lset
+```ls``` using its equality comparator.
+
+    (lset-count ls)
+
+* ```ls``` - lset instance
+
+Returns the number of elements in given lset.
+  
+    (lset-add ls [el ...])
+
+* ```ls``` - lset instance
+* ```el``` - element(s) to add
+
+Adds given element(s) ```el``` to the lset instance ```ls``` returning
+a new lset instance.
+
+    (lset-remove ls el)
+
+* ```ls``` - lset instance
+* ```el``` - element to remove
+
+If given lset instance ```ls``` contains the element ```el```
+provided, it is removed and the new lset is returned. If the element
+is not contained in ```ls```, it is returned intact.
+
+    (list->lset lst [comparator])
+
+* ```lst``` - list to convert
+* ```comparator``` - equality comparison procedure, defaults to ```equal?```
+
+Returns a new lset with the comparator provided containing all
+elements in given list.
+
+    (lset->list ls)
+
+* ```ls``` - lset instance
+
+Returns the list of elements in given lset.
+
+    (lset-merge ls1 ls2)
+
+* ```ls1``` - lset instance
+* ```ls2``` - lset instance
+
+Returns a new lset instance with all elements in both lset instances given.
+
+    (lset-intersect ls1 ls2)
+
+* ```ls1``` - lset instance
+* ```ls2``` - lset instance
+
+Returns a new lset instance containing elements present both in
+```ls1``` and ```ls2```.
+
+    (lset-subtract ls1 ls2)
+
+Returns a new lset instance from ```ls1``` with all elements in
+```ls2``` removed from it.
+
 ### String
 
     (import util-string)