Changeset 4482 for trunk/library/numberlistp.lgt

Timestamp:

10/04/08 12:30:36 (3 months ago)

Author:

pmoura

Message:

Modified the implementation of the predicate product/2 in the library object "numberlist" to fail for empty lists.

Files:

• trunk/library/numberlistp.lgt (modified) (3 diffs)

trunk/library/numberlistp.lgt

@@ -3 +3 @@
 
     :- info([
-        version is 1.1,
+        version is 1.2,
         author is 'Paulo Moura',
-        date is 2007/4/20,
+        date is 2008/9/15,
         comment is 'List of numbers protocol.']).
 
@@ -11 +11 @@
     :- mode(product(+list(number), ?number), zero_or_one).
     :- info(product/2,
-        [comment is 'Calculates the product of all list values.',
+        [comment is 'Calculates the product of all list numbers. Fails if the list is empty.',
          argnames is ['List', 'Product']]).
 
     :- public(sum/2).
-    :- mode(sum(+list(number), ?number), zero_or_one).
+    :- mode(sum(+list(number), ?number), one).
     :- info(sum/2,
-        [comment is 'Calculates the sum of all list values.',
+        [comment is 'Calculates the sum of all list numbers. Returns zero if the list is empty.',
          argnames is ['List', 'Sum']]).
 
@@ -23 +23 @@
     :- mode(average(+list(number), ?float), zero_or_one).
     :- info(average/2,
-        [comment is 'Calculates the average of a list  of values.',
+        [comment is 'Calculates the average (i.e. arithmetic mean) of a list of numbers. Fails if the list is empty.',
          argnames is ['List', 'Average']]).