[nqp] Add named argument handling.

src/NQP/Actions.pm

@@ -116,10 +116,19 @@ method statement_control:sym<return>($/) {
 
 ## Terms
 
+method noun:sym<colonpair>($/) { make $<colonpair>.ast; }
 method noun:sym<variable>($/) { make $<variable>.ast; }
 method noun:sym<scope_declarator>($/) { make $<scope_declarator>.ast; }
 method noun:sym<routine_declarator>($/) { make $<routine_declarator>.ast; }
 
+method colonpair($/) {
+    my $past := $<circumfix> 
+                ?? $<circumfix>[0].ast 
+                !! PAST::Val.new( :value( !$<not> ) );
+    $past.named( ~$<identifier> );
+    make $past;
+}
+
 method variable($/) {
     my $past := PAST::Var.new( :name(~$/) );
     if $<twigil>[0] eq '*' { 

src/NQP/Grammar.pm

@@ -4,6 +4,13 @@ token TOP {
     <comp_unit> 
 }
 
+## Lexer stuff
+
+token identifier { <ident> }
+
+
+## Top-level rules
+
 token comp_unit { 
     <.newpad>
     <statementlist> 
@@ -96,10 +103,19 @@ token statement_control:sym<return> {
 
 ## Terms
 
+token noun:sym<colonpair>          { <colonpair> }
 token noun:sym<variable>           { <variable> }
 token noun:sym<scope_declarator>   { <scope_declarator> }
 token noun:sym<routine_declarator> { <routine_declarator> }
 
+token colonpair {
+    ':' 
+    [ 
+    | $<not>='!' <identifier>
+    | <identifier> <circumfix>?
+    ]
+}
+
 token variable {
     <sigil> <twigil>? <desigilname=ident>
 }
@@ -154,7 +170,7 @@ rule default_value { '=' <EXPR('i=')> }
 proto token term { <...> }
 
 token term:sym<identifier> {
-    <identifier=ident> <args>
+    <identifier> <args>
 }
 
 token args {

src/cheats/hll-compiler.pir

@@ -20,7 +20,7 @@
 
     null parseactions
     $S0 = options['target']
-#    if $S0 == 'parse' goto have_parseactions
+    if $S0 == 'parse' goto have_parseactions
     parseactions = self.'parseactions'()
   have_parseactions:
 

t/nqp/23-named-args.t

@@ -0,0 +1,20 @@
+#! nqp
+
+# test named parameters and arguments
+
+plan(4);
+
+sub f1 ($x, :$y) { $x - $y; }
+say('ok ', f1(2, :y(1)), ' # named args passable');
+
+sub f2 ($x, :$y) { $x; }
+say('ok ', f2(2), ' # named args ignorable');
+
+sub f3 (:$x, :$y) { $x - $y; }
+say('ok ', f3(:y(2), :x(5)), ' # args reorderable');
+
+sub f4 ($w, $x, :$y, :$z) { $w + $x + $y + $z; }
+say('ok ', f4(:z(2), -3, :y(1), 4), ' # named/positional intermixable');
+
+
+# XXX: test mandatory named args are actually mandatory