added 'until' keyword.

doc/LOLHALP

@@ -1,7 +1,6 @@
 The below things should be fairly straightforward to implement. Just look in
 the commit logs at how similar features were implemented.
 
-* 'until' keywords.
 * 'loop' keyword. (at least the infinitely looping version is easy.)
 * 'repeat' keyword.
 * 'ENTER', 'LEAVE', 'FIRST', 'NEXT', and 'LAST' phasers.

lib/Yapsi.pm

@@ -17,11 +17,11 @@ grammar Yapsi::Perl6::Grammar {
                        || <declaration> || <block>
                        || <saycall> || <increment> || <decrement> }
     token statement_control { <statement_control_if>
-                              || <statement_control_while> 
+                              || <statement_control_while_until> 
                               || <statement_control_unless> }
     rule  statement_control_if { 'if' <expression> <block>
                                  [ 'else' <else=.block> ]? }
-    rule  statement_control_while { 'while' <expression> <block> }
+    rule  statement_control_while_until { $<keyword>=[ 'while' | 'until' ] <expression> <block> }
     rule statement_control_unless { 'unless' <expression> <block> }
     token lvalue { <declaration> || <variable> || <increment> }
     token value { <variable> || <literal> || <declaration> || <saycall>
@@ -120,7 +120,7 @@ class Yapsi::Compiler {
                 my $*c = 0; # unique register counter
                 my $*l = 0; # unique label    counter
                 my @skip = 'block', 'statement_control_if',
-                           'statement_control_while', 'statement_control_unless';
+                           'statement_control_while_until', 'statement_control_unless';
                 my &sicify = -> $/, $key {
                     if $m !=== $/ && $key eq 'block' {
                         my $register = self.unique-register;
@@ -176,7 +176,7 @@ class Yapsi::Compiler {
                             "call $register";
                         push @blocksic, "`label $after-unless";
                     }
-                    elsif $key eq 'statement_control_while' {
+                    elsif $key eq 'statement_control_while_until' {
                         my $before-while = self.unique-label;
                         my $after-while = self.unique-label;
                         push @blocksic, "`label $before-while";
@@ -187,7 +187,14 @@ class Yapsi::Compiler {
                             :action(&sicify)
                         );
                         my ($register, $) = $<expression>.ast.list;
-                        push @blocksic, "jf $register, $after-while";
+                        given $<keyword> {
+                            when / while / {
+                                push @blocksic, "jf $register, $after-while";
+                            }
+                            when / until / {
+                                push @blocksic, "jt $register, $after-while";
+                            }
+                        }
                         my $block-name = $<block>.ast<name>;
                         $register = self.unique-register;
                         push @blocksic,

t/compiler.t

@@ -31,6 +31,9 @@ my @programs-that-compile =
     'my $a; if $a {}',
     'if my $a {} else { say 42 }',
     'my $a; while $a { say $a }',
+    'unless 0 { say 42 }',
+    'my $a=0; unless $a { say $a }',
+    'my $a=0; until $a { say 42; ++$a; }',
 ;
 
 sub escape($string) { $string.subst("\n", "\\n", :g) }
@@ -61,8 +64,8 @@ my @programs-that-don't-compile =   # '
     'if $a {}',
     'if 42 { $a }',
     'if 5 {} else { $a }',
-    'unless 0 { say "unless" }',
-    'unless $a { say $a }'
+    'unless {} ',
+    'unless a {} ',
 ;
 
 for @programs-that-don't-compile -> $program { # '

t/runtime.t

@@ -36,6 +36,8 @@ my @tests =
     'my $a; while $a { say 42 }',      "",          'non-executing while loop',
     'my $a = 42;unless $a { say 24 }',  "",          'non-executing unless block',
     'unless 0 { say 42 }',  "42\n",       'executing unless block',
+    'my $a=0; until $a { say 42; ++$a; }',"42\n", 'executing until loop structure',
+    'until 42 { say 24; }'              , "",     'non-executing until loop structure',
 #   TODO -- Need to "instantiate" lexpads from some kind of "proto-lexpads"
 #    'my $a = 3; while --$a { say my $b; $b = 42 }', "Any()\nAny()\n",
 #                'each time a block is entered, it gets a fresh lexical pad',