support unless+elsif+else

rakudo-p5 · Apr 7, 2013 · b9c89f6 · b9c89f6
1 parent c1b6b95
commit b9c89f6
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Showing 3 changed files with 20 additions and 15 deletions.
diff --git a/TODO_compound_statements.md b/TODO_compound_statements.md
@@ -11,6 +11,8 @@ Done:
     if (EXPR) BLOCK elsif (EXPR) BLOCK ... else BLOCK
     unless (EXPR) BLOCK
     unless (EXPR) BLOCK else BLOCK
+    unless (EXPR) BLOCK elsif (EXPR) BLOCK ...
+    unless (EXPR) BLOCK elsif (EXPR) BLOCK ... else BLOCK
     LABEL while (EXPR) BLOCK
     LABEL for (EXPR; EXPR; EXPR) BLOCK
     LABEL for VAR (LIST) BLOCK
@@ -20,8 +22,6 @@ Done:
 Almost (LHF):
 
     given (EXPR) BLOCK
-    unless (EXPR) BLOCK elsif (EXPR) BLOCK ...
-    unless (EXPR) BLOCK elsif (EXPR) BLOCK ... else BLOCK
     LABEL until (EXPR) BLOCK
 
 Todo:

diff --git a/lib/Perl6/P5Actions.pm b/lib/Perl6/P5Actions.pm
@@ -822,36 +822,34 @@ class Perl6::P5Actions is HLL::Actions does STDActions {
 
 
     ## Statement control
-
-    method statement_control:sym<if>($/) {
-        $*W.get_env('V5DEBUG') && say("statement_control:sym<if>($/)");
+    sub if_statement($/) {
         my $count := +$<xblock> - 1;
         my $past := xblock_immediate( $<xblock>[$count].ast );
-        # push the else block if any, otherwise 'if' returns C<Nil> (per S04)
+        # push the else block if any
         $past.push( $<else>
                     ?? pblock_immediate( $<else>[0].ast )
                     !!  QAST::Var.new(:name('Nil'), :scope('lexical'))
         );
-        # build if/then/elsif structure
+        # build if/unless + elsif + else structure
         while $count > 0 {
             $count--;
             my $else := $past;
             $past := xblock_immediate( $<xblock>[$count].ast );
             $past.push($else);
         }
-        make $past;
+        $past;
+    }
+
+    method statement_control:sym<if>($/) {
+        $*W.get_env('V5DEBUG') && say("statement_control:sym<if>($/)");
+        make if_statement($/)
     }
 
     method statement_control:sym<unless>($/) {
         $*W.get_env('V5DEBUG') && say("statement_control:sym<unless>($/)");
-        my $past := xblock_immediate( $<xblock>.ast );
+        my $past := if_statement($/);
         $past.op('unless');
-        # push the else block if any
-        $past.push( $<else>
-                    ?? pblock_immediate( $<else>[0].ast )
-                    !!  QAST::Var.new(:name('Nil'), :scope('lexical'))
-        );
-        make $past;
+        make $past
     }
 
     method statement_control:sym<while>($/) {

diff --git a/lib/Perl6/P5Grammar.pm b/lib/Perl6/P5Grammar.pm
@@ -1423,6 +1423,13 @@ grammar Perl6::P5Grammar is HLL::Grammar does STD5 {
     rule statement_control:sym<unless> {
         <sym>
         <xblock>
+        [
+            [
+            | 'else'\h*'if' <.typed_panic: 'X::Syntax::Malformed::Elsif'>
+            | 'elif' { $/.CURSOR.typed_panic('X::Syntax::Malformed::Elsif', what => "elif") }
+            | 'elsif' <xblock>
+            ]
+        ]*
         [ 'else' <else=.sblock> ]?
     }