Add partial-apply

extra/partial-apply/partial-apply.factor

@@ -0,0 +1,26 @@
+
+USING: kernel sequences quotations math parser
+       shuffle combinators.cleave combinators.lib sequences.lib ;
+
+IN: partial-apply
+
+! Basic conceptual implementation. Todo: get it to compile.
+
+: apply-n ( obj quot i -- quot ) 1+ [ -nrot ] curry swap compose curry ;
+
+SYMBOL: _
+
+SYMBOL: ~
+
+: blank-positions ( quot -- seq )
+  [ length 2 - ] [ _ indices ] bi [ - ] map-with ;
+  
+: partial-apply ( pattern -- quot )
+  [ blank-positions length nrev ]
+  [ peek 1quotation ]
+  [ blank-positions ]
+  tri
+  [ apply-n ] each ;
+
+: $[ \ ] [ >quotation ] parse-literal \ partial-apply parsed ; parsing
+