added composition operator "of"

fn/fns.fn

@@ -0,0 +1 @@
+print (car of cdr of cdr)([[], [], ['a']]);

fn/pettersson92.fn

@@ -109,7 +109,7 @@ let
     typedef code {
         symbol(string) |
         case(code, list(code)) |
-        of(pattern, code) |
+        when(pattern, code) |
         letrec(list(#(code, code)), code) |
         lambda(list(code), code) |
         apply(code, list(code))
@@ -195,7 +195,7 @@ let
                         }
                     }
                     (case(cond, rules)) { case(h(cond), rules |> h) }
-                    (of(pattern, action)) { of(pattern, h(action)) }
+                    (when(pattern, action)) { when(pattern, h(action)) }
                     (letrec(defs, body)) {
                         letrec(defs |> fn {
                             (#(name, value)) { #(h(name), h(value)) }
@@ -601,7 +601,7 @@ let
                 }
             }
             fn translateArc(arc(pat, _, state)) {
-                of(pat, translateState(state))
+                when(pat, translateState(state))
             }
             fn translateLambdas(lambdas) {
                 dict.values(lambdas) |> fn {
@@ -674,29 +674,29 @@ in
 //         #(symbol("Q$1"), lambda([symbol("x$2$0")], symbol("x$2$0"))),
 //         #(symbol("error"), lambda([], symbol("error")))],
 //         case(symbol("x$1"), [
-//             of(x$1=1,
+//             when(x$1=1,
 //                 case(symbol("x$2"), [
-//                     of(x$2=#(x$2$0=_, x$2$1=_),
+//                     when(x$2=#(x$2$0=_, x$2$1=_),
 //                         case(symbol("x$3"), [
-//                             of(x$3=cons(x$3$0=_, x$3$1=_),
+//                             when(x$3=cons(x$3$0=_, x$3$1=_),
 //                                 case(symbol("x$2$1"), [
-//                                     of(x$2$1=3,
+//                                     when(x$2$1=3,
 //                                         apply(symbol("cons"), [
 //                                             symbol("x$3$0"),
 //                                             symbol("x$3$1")])),
-//                                     of(x$2$1=_,
+//                                     when(x$2$1=_,
 //                                         apply(symbol("error"),
 //                                             []))])),
-//                             of(x$3=nil,
+//                             when(x$3=nil,
 //                                 apply(symbol("Q$1"),
 //                                     [symbol("x$2$0")]))]))])),
-//             of(x$1=_,
+//             when(x$1=_,
 //                 case(symbol("x$2"), [
-//                     of(x$2=#(x$2$0=_, x$2$1=_),
+//                     when(x$2=#(x$2$0=_, x$2$1=_),
 //                         case(symbol("x$3"), [
-//                             of(x$3=nil,
+//                             when(x$3=nil,
 //                                 apply(symbol("Q$1"),
 //                                     [symbol("x$2$0")])),
-//                             of(x$3=_,
+//                             when(x$3=_,
 //                                 apply(symbol("error"),
 //                                     []))]))]))])))

src/preamble.fn

@@ -141,6 +141,8 @@ fn error_(line, file, message) {
     exit(1);
 }
 
+infix right 120 "of" fn (f, g, x) { f(g(x)) };
+
 fn append {
     ([], b) { b }
     (h @ t, b) { h @ append(t, b) }

vim/syntax/fnatural.vim

@@ -34,7 +34,7 @@ syntax match fnOperator "\v\|"
 syntax match fnOperator "\v\<"
 syntax match fnOperator "\v\>"
 syntax match fnOperator "\v\="
-syntax keyword fnOperator and nand or nor not xor xnor
+syntax keyword fnOperator and nand or nor not xor xnor of
 highlight link fnOperator Operator
 
 syntax region fnString start=/\v'/ skip=/\v\\./ end=/\v'/