Add sub calls to example compiler.

src/Squaak/Actions.pm

@@ -89,6 +89,21 @@ method statement:sym<if>($/) {
     make $past;
 }
 
+method statement:sym<sub_call>($/) {
+    my $invocant := $<primary>.ast;
+    my $past     := $<arguments>.ast;
+    $past.unshift($invocant);
+    make $past;
+}
+
+method arguments($/) {
+    my $past := PAST::Op.new( :pasttype('call'), :node($/) );
+    for $<expression> {
+        $past.push($_.ast);
+    }
+    make $past;
+}
+
 method statement:sym<throw>($/) {
     make PAST::Op.new( $<expression>.ast,
                        :pirop('throw'),

src/Squaak/Grammar.pm

@@ -61,6 +61,14 @@ rule statement:sym<if> {
     'end'
 }
 
+rule statement:sym<sub_call> {
+    <primary> <arguments>
+}
+
+rule arguments {
+    '(' [<expression> ** ',']? ')'
+}
+
 rule statement:sym<throw> {
     <sym> <expression>
 }