{ $description "Raises " { $snippet "x" } " to the power of " { $snippet "y" } ". If " { $snippet "y" } " is an integer the answer is computed exactly, otherwise a floating point approximation is used." }
{ $errors "Throws an error if " { $snippet "x" } " and " { $snippet "y" } " are both integer 0." } ;
+HELP: 10^
+{ $values { "x" number } { "y" number } }
+{ $description "Raises " { $snippet "x" } " to the power of 10. If " { $snippet "x" } " is an integer the answer is computed exactly, otherwise a floating point approximation is used." } ;
+
HELP: gcd
{ $values { "x" integer } { "y" integer } { "a" integer } { "d" integer } }
{ $description "Computes the positive greatest common divisor " { $snippet "d" } " of " { $snippet "x" } " and " { $snippet "y" } ", and another value " { $snippet "a" } " satisfying:" { $code "a*y = d mod x" } }
+{ $values { "n" number } { "quot1" quotation } { "quot2" quotation } }
+{ $description "Makes an implicit check if the number is zero. A zero is dropped and " { $snippet "quot1" } " is called. Otherwise, if the number is not zero, " { $snippet "quot2" } " is called on it." }
+{ $example
+ "USING: kernel math prettyprint sequences ;"
+ "3 [ \"zero\" ] [ sq ] if-zero ."
+ "9"
+} ;
+
+HELP: when-zero
+{ $values
+ { "n" number } { "quot" "the first quotation of an " { $link if-zero } } }
+{ $description "Makes an implicit check if the sequence is empty. A zero is dropped and the " { $snippet "quot" } " is called." }
+{ $examples "This word is equivalent to " { $link if-zero } " with an empty second quotation:"
+ { $example
+ "USING: sequences prettyprint ;"
+ "0 [ 4 ] [ ] if-zero ."
+ "4"
+ }
+ { $example
+ "USING: sequences prettyprint ;"
+ "0 [ 4 ] when-zero ."
+ "4"
+ }
+} ;
+
+HELP: unless-zero
+{ $values
+ { "n" number } { "quot" "the second quotation of an " { $link if-empty } } }
+{ $description "Makes an implicit check if the number is zero. A zero is dropped. Otherwise, the " { $snippet "quot" } " is called on the number." }
+{ $examples "This word is equivalent to " { $link if-zero } " with an empty first quotation:"