nmap-as and nmap combinators

basis/generalizations/generalizations-docs.factor

@@ -237,9 +237,17 @@ HELP: nspread
 } ;
 
 HELP: neach
-{ $values { "n" integer } }
+{ $values { "...seq" "a set of " { $snippet "n" } " sequences" } { "quot" "a quotation with stack effect " { $snippet "( ...element -- )" } } { "n" integer } }
 { $description "A generalization of " { $link each } ", " { $link 2each } ", and " { $link 3each } " that can iterate over any number of sequences in parallel." } ;
 
+HELP: nmap
+{ $values { "...seq" "a set of " { $snippet "n" } " sequences" } { "quot" "a quotation with stack effect " { $snippet "( ...element -- result )" } } { "n" integer } { "result" "a sequence of the same type as the first " { $snippet "seq" } } }
+{ $description "A generalization of " { $link map } ", " { $link 2map } ", and " { $link 3map } " that can map over any number of sequences in parallel." } ;
+
+HELP: nmap-as
+{ $values { "...seq" "a set of " { $snippet "n" } " sequences" } { "quot" "a quotation with stack effect " { $snippet "( ...element -- result )" } } { "exemplar" sequence } { "n" integer } { "result" "a sequence of the same type as " { $snippet "exemplar" } } }
+{ $description "A generalization of " { $link map-as } ", " { $link 2map-as } ", and " { $link 3map-as } " that can map over any number of sequences in parallel." } ;
+
 HELP: mnswap
 { $values { "m" integer } { "n" integer } }
 { $description "Swaps the top " { $snippet "m" } " stack elements with the " { $snippet "n" } " elements directly underneath." }
@@ -350,6 +358,8 @@ ARTICLE: "combinator-generalizations" "Generalized combinators"
     ncleave
     nspread
     neach
+    nmap
+    nmap-as
 } ;
 
 ARTICLE: "other-generalizations" "Additional generalizations"

basis/generalizations/generalizations-tests.factor

@@ -82,6 +82,10 @@ IN: generalizations.tests
 
 : neach-test ( a b c d -- )
     [ 4 nappend print ] 4 neach ;
+: nmap-test ( a b c d -- e )
+    [ 4 nappend ] 4 nmap ;
+: nmap-as-test ( a b c d -- e )
+    [ 4 nappend ] [ ] 4 nmap-as ;
 
 [ """A1a!
 B2b@
@@ -94,3 +98,21 @@ D4d$
     { "!" "@" "#" "$" }
     [ neach-test ] with-string-writer
 ] unit-test
+
+[ { "A1a!" "B2b@" "C3c#" "D4d$" } ]
+[ 
+    { "A" "B" "C" "D" }
+    { "1" "2" "3" "4" }
+    { "a" "b" "c" "d" }
+    { "!" "@" "#" "$" }
+    nmap-test
+] unit-test
+
+[ [ "A1a!" "B2b@" "C3c#" "D4d$" ] ]
+[ 
+    { "A" "B" "C" "D" }
+    { "1" "2" "3" "4" }
+    { "a" "b" "c" "d" }
+    { "!" "@" "#" "$" }
+    nmap-as-test
+] unit-test

basis/generalizations/generalizations.factor

@@ -128,5 +128,11 @@ MACRO: (neach) ( n -- )
     dup dup dup
     '[ [ [ _ nmin-length ] _ nkeep [ _ nnth-unsafe ] _ ncurry ] dip compose ] ;
 
-: neach ( ... seq quot n -- )
+: neach ( ...seq quot n -- )
     (neach) each-integer ; inline
+
+: nmap-as ( ...seq quot exemplar n -- result )
+    '[ _ (neach) ] dip map-integers ; inline
+
+: nmap ( ...seq quot n -- result )
+    dup '[ [ _ npick ] dip swap ] dip nmap-as ; inline