parse reference (needed by reference link)

src/Compiler.pir

@@ -261,6 +261,18 @@ Return generated HTML for all of its children.
     .return (code)
 .end
 
+=item html(Markdown::Reference node)
+
+=cut
+
+.sub 'html' :method :multi(_,['Markdown';'Reference'])
+    .param pmc node
+    .local pmc code
+    new code, 'CodeString'
+    set code, ''
+    .return (code)
+.end
+
 =item html(Markdown::Email node)
 
 =cut

src/Node.pir

@@ -31,6 +31,7 @@ for Markdown.
     p6meta.'new_class'('Markdown::OrderedList', 'parent'=>base)
     p6meta.'new_class'('Markdown::Para', 'parent'=>base)
     p6meta.'new_class'('Markdown::RefLink', 'parent'=>base)
+    p6meta.'new_class'('Markdown::Reference', 'parent'=>base)
     p6meta.'new_class'('Markdown::Space', 'parent'=>base)
     p6meta.'new_class'('Markdown::Strong', 'parent'=>base)
     p6meta.'new_class'('Markdown::Title', 'parent'=>base)

src/parser/actions.pm

@@ -255,6 +255,10 @@ method AutoLinkEmail($/) {
     make Markdown::Email.new( :text( $/[0].text() ) );
 }
 
+method Reference($/) {
+    make Markdown::Reference.new( );
+}
+
 method Code($/) {
     make Markdown::Code.new( :text( $/[0].text() ) );
 }

src/parser/grammar.pg

@@ -19,6 +19,7 @@ token TOP {
 token Block {
     <.BlankLine>* [
         | <BlockQuote> {*}      #= BlockQuote
+        | <Reference> {*}       #= Reference
         | <HorizontalRule> {*}  #= HorizontalRule
         | <Heading> {*}         #= Heading
         | <OrderedList> {*}     #= OrderedList
@@ -367,12 +368,52 @@ token AutoLinkEmail {
 
 token _Gt { '>' }
 
+token Reference {
+    <.NonindentSpace> <!_EmptyLabel> <Label> ':' <.Spnl> <RefSrc> <.Spnl> <RefTitle> <.BlankLine>*
+    {*}
+}
+
 token Label {
     '[' [ <!_EndLabel> <Inline> ]* ']'
 }
 
 token _EndLabel { ']' }
 
+token RefSrc { <.Nonspacechar>+ }
+
+token RefTitle {
+    | <RefTitleSingle>
+    | <RefTitleDouble>
+    | <RefTitleParens>
+    | <EmptyTitle>
+}
+
+token EmptyTitle { '' }
+
+token RefTitleSingle {
+    '\'' ( [ <!_RefTitleS> . ]* ) '\''
+}
+
+token _RefTitleS {
+    [ '\'' <.Sp> <.Newline> | <.Newline> ]
+}
+
+token RefTitleDouble {
+    '"' ( [ <!_RefTitleD> . ]* ) '"'
+}
+
+token _RefTitleD {
+    [ '"' <.Sp> <.Newline> | <.Newline> ]
+}
+
+token RefTitleParens {
+    '(' ( [ <!_RefTitleP> . ]* ) ')'
+}
+
+token _RefTitleP {
+    [ ')' <.Sp> <.Newline> | <.Newline> ]
+}
+
 token Ticks1 { '`' }
 token Ticks2 { '``' }
 token Ticks3 { '```' }