Implement elif.

src/Snake/Actions.nqp

@@ -62,8 +62,15 @@ method simple-statement:sym<expr>($/) { make $<EXPR>.ast; }
 
 # 8: Compound statements
 method compound-statement:sym<if>($/) {
-    my $ast := QAST::Op.new(:op<if>, $<EXPR>.ast, $<suite>[0].ast);
-    $ast.push($<suite>[1].ast) if +$<suite> > 1;
+    my $ast := QAST::Op.new(:op<if>, $<EXPR>.ast, $<suite>.ast);
+    my $cur := $ast;
+    while nqp::elems($<elif>) > 0 {
+        my $new := QAST::Op.new(:op<if>, nqp::shift($<elif>).ast, nqp::shift($<elif>).ast);
+        $cur.push: $new;
+        $cur := $new;
+    }
+    $cur.push($<else>.ast) if $<else>;
+
     make $ast;
 }
 

src/Snake/Grammar.nqp

@@ -194,7 +194,8 @@ proto token compound-statement {*}
 rule compound-statement:sym<if> {
     :my int $indent := nqp::atpos_i(@*INDENT, 0);
     <sym> <EXPR> ':' <suite>
-    [<.INDENT: $indent> 'else' ':' <suite>]?
+    [<.INDENT: $indent> 'elif' <elif=.EXPR> ':' <elif=.suite>]?
+    [<.INDENT: $indent> 'else' ':' <else=.suite>]?
 }
 
 proto token suite {*}

t/sanity/if.t

@@ -1,8 +1,16 @@
+nqp::say('1..2')
+
 if 1:
-    nqp::say('1..1')
     if 0:
         nqp::say("BAIL OUT!")
 else:
     nqp::print('not ')
 
 nqp::say('ok 1 - else attachment')
+
+if 0:
+    nqp::say("BAIL OUT!")
+elif 1:
+    nqp::say("ok 2 - elif")
+else:
+    nqp::say("BAIL OUT!")