[css3-syntax] Allowed the 'consume a primitive' subalgo to return nothing when it finds a non-preserved token.

--HG--
extra : rebase_source : f6b10d5de666649e33f92a8b84a154cae4ba1785

Author: tabatkins

css3-syntax/Overview.html

@@ -11,10 +11,10 @@
 
   <meta content="CSS Syntax Module Level 3 (CSS3 Syntax)" name=dcterms.title>
   <meta content=text name=dcterms.type>
-  <meta content=2013-01-30 name=dcterms.issued>
+  <meta content=2013-01-31 name=dcterms.issued>
   <meta content="http://dev.w3.org/csswg/css3-syntax/" name=dcterms.creator>
   <meta content=W3C name=dcterms.publisher>
-  <meta content="http://www.w3.org/TR/2013/ED-css3-syntax-20130130/"
+  <meta content="http://www.w3.org/TR/2013/ED-css3-syntax-20130131/"
    name=dcterms.identifier>
   <link href="#contents" rel=contents>
   <link href="#index" rel=index>
@@ -48,7 +48,7 @@
 
    <h1>CSS Syntax Module Level 3</h1>
 
-   <h2 class="no-num no-toc" id=longstatus-date>Editor's Draft 30 January
+   <h2 class="no-num no-toc" id=longstatus-date>Editor's Draft 31 January
     2013</h2>
 
    <dl>
@@ -2745,18 +2745,11 @@ <h2 id=parsing><span class=secno>5. </span> Parsing</h2>
    <dt><dfn id=preserved-tokens>preserved tokens</dfn>
 
    <dd> The tokens that can appear in the tree are: ident, hash, string, url,
-    delim, number, percentage, dimension, unicode-range, whitespace, cdo,
-    cdc, colon, semicolon, at-keyword, ], ), and }.
+    delim, number, percentage, dimension, unicode-range, whitespace, colon,
+    semicolon, at-keyword,
     <p class=note> This means that the following tokens emitted by the
      tokenizer stage will <strong>not</strong> appear in the stylesheet
-     object: function, bad-string, bad-url, [, (, {.
-
-    <p class=issue> Currently bad-url and bad-string tokens can also appear
-     in the tree. Is it worth it to complexify the parser with error-handling
-     for this kind of thing (every call to "<a
-     href="#consume-a-primitive0"><i>consume a primitive</i></a>" might
-     fail)? Or should I just leave them alone, assume that grammar-checking
-     will kill them, and leave their serialization undefined?
+     object: function, bad-string, bad-url, cdo, cdc, [, ], (, ), {. and }.
 
    <dt><dfn id=function>function</dfn>
 
@@ -2896,6 +2889,8 @@ <h4 id=top-level-mode><span class=secno>5.3.1. </span> <dfn
 
    <dd> Do nothing. Remain in this mode.
 
+   <dt>bad-string token
+
    <dt>at-keyword token
 
    <dd> Create an at-rule with its name set to the value of the <a
@@ -2995,9 +2990,18 @@ <h4 id=at-rule-prelude-mode><span class=secno>5.3.2. </span> <dfn
 
    <dt>anything else
 
-   <dd> <a href="#consume-a-primitive0"><i>Consume a primitive</i></a> and
-    append the returned value to the prelude of the <a
+   <dd> <a href="#consume-a-primitive0"><i>Consume a primitive</i></a>. If
+    anything was returned, append the returned value to the prelude of the <a
     href="#current-rule"><i>current rule</i></a>. Remain in this mode.
+    <p> Otherwise, this is a <i>parse error</i>. <a
+     href="#discard-the-current-rule0"><i>Discard the current rule</i></a>.
+     If the <a href="#current-rule"><i>current rule</i></a> is <a
+     href="#declaration-filled"><i>declaration-filled</i></a> or <a
+     href="#rule-filled"><i>rule-filled</i></a>, switch to the <a
+     href="#next-block-error-mode0"><i>next-block error mode</i></a>;
+     otherwise, switch to the <a
+     href="#next-block-or-statement-error-mode0"><i>next-block-or-statement
+     error mode</i></a>.
   </dl>
 
   <h4 id=rule-block-mode><span class=secno>5.3.3. </span> <dfn
@@ -3076,9 +3080,13 @@ <h4 id=selector-mode><span class=secno>5.3.4. </span> <dfn
 
    <dt>anything else
 
-   <dd> <a href="#consume-a-primitive0"><i>Consume a primitive</i></a> and
-    append the returned value to the selector of the <a
-    href="#current-rule"><i>current rule</i></a>. Remain in this mode.
+   <dd> <a href="#consume-a-primitive0"><i>Consume a primitive</i></a>. If
+    anything was returned, append the returned value to the selector of the
+    <a href="#current-rule"><i>current rule</i></a>. Remain in this mode.
+    <p> Otherwise, this is a <i>parse error</i>. <a
+     href="#discard-the-current-rule0"><i>Discard the current rule</i></a>.
+     Switch to the <a href="#next-block-error-mode0"><i>next-block error
+     mode</i></a>.
   </dl>
 
   <h4 id=declaration-block-mode><span class=secno>5.3.5. </span> <dfn
@@ -3221,9 +3229,13 @@ <h4 id=declaration-value-mode><span class=secno>5.3.7. </span> <dfn
     match for one of the property names on the <a
     href="#hashless-color-quirk-list"><i>hashless color quirk list</i></a>,
     <a href="#consume-a-primitive-with-the-hashless-co0"><i>consume a
-    primitive with the hashless color quirk</i></a> and append the returned
-    value to the value of the <a href="#current-declaration"><i>current
-    declaration</i></a>. Remain in this mode.
+    primitive with the hashless color quirk</i></a>. If anything was
+    returned, append the returned value to the value of the <a
+    href="#current-declaration"><i>current declaration</i></a> and remain in
+    this mode; otherwise, unset the <a href="#current-declaration"><i>current
+    declaration</i></a> and switch to the <a
+    href="#next-declaration-error-mode0"><i>next-declaration error
+    mode</i></a>.
     <p> Otherwise, if the <a href="#quirks-mode"><i>quirks mode</i></a> flag
      is set, and the <a href="#current-declaration"><i>current
      declaration's</i></a> name is an <a
@@ -3232,14 +3244,21 @@ <h4 id=declaration-value-mode><span class=secno>5.3.7. </span> <dfn
      href="#unitless-length-quirk-list"><i>unitless length quirk
      list</i></a>, <a
      href="#consume-a-primitive-with-the-unitless-le0"><i>consume a primitive
-     with the unitless length quirk</i></a> and append the returned value to
-     the value of the <a href="#current-declaration"><i>current
-     declaration</i></a>. Remain in this mode.
+     with the unitless length quirk</i></a>. If anything was returned, append
+     the returned value to the value of the <a
+     href="#current-declaration"><i>current declaration</i></a> and remain in
+     this mode; otherwise, unset the <a
+     href="#current-declaration"><i>current declaration</i></a> and switch to
+     the <a href="#next-declaration-error-mode0"><i>next-declaration error
+     mode</i></a>.
 
     <p> Otherwise, <a href="#consume-a-primitive0"><i>consume a
-     primitive</i></a> and append the returned value to the value of the <a
-     href="#current-declaration"><i>current declaration</i></a>. Remain in
-     this mode.
+     primitive</i></a>. If anything was returned, append the returned value
+     to the value of the <a href="#current-declaration"><i>current
+     declaration</i></a> and remain in this mode; otherwise, unset the <a
+     href="#current-declaration"><i>current declaration</i></a> and switch to
+     the <a href="#next-declaration-error-mode0"><i>next-declaration error
+     mode</i></a>.
   </dl>
 
   <h4 id=declaration-important-mode><span class=secno>5.3.8. </span> <dfn
@@ -3425,6 +3444,10 @@ <h3 id=consume-a-primitive><span class=secno>5.4. </span> <dfn
    token</i></a> is an EOF token, <a href="#finish-parsing0"><i>finish
    parsing</i></a>.
 
+  <p> Otherwise, if the <a href="#current-input-token"><i>current input
+   token</i></a> is a cdo token, cdc token, } token, ] token, ) token,
+   bad-string token, or bad-url token, return nothing.
+
   <p> Otherwise, return the <a href="#current-input-token"><i>current input
    token</i></a>.
 
@@ -3554,6 +3577,8 @@ <h3 id=consume-a-simple-block><span class=secno>5.7. </span> <dfn
    href="#current-input-token"><i>current input token</i></a>. This is the
    <dfn id=current-block>current block</dfn>.
 
+  <p> Initialize a <var>valid</var> flag to true.
+
   <p> Repeatedly consume the <a href="#next-input-token"><i>next input
    token</i></a> and process it as follows:
 
@@ -3562,13 +3587,15 @@ <h3 id=consume-a-simple-block><span class=secno>5.7. </span> <dfn
 
    <dt><a href="#ending-token"><i>ending token</i></a>
 
-   <dd> Return the block.
+   <dd> If the <var>valid</var> flag is true, return the block.
+    <p> Otherwise, return nothing.
 
    <dt>anything else
 
-   <dd> <a href="#consume-a-primitive0"><i>Consume a primitive</i></a> and
-    append the returned value to the value of the <a
-    href="#current-block"><i>current block</i></a>.
+   <dd> <a href="#consume-a-primitive0"><i>Consume a primitive</i></a>. If
+    anything was returned, append the returned value to the value of the <a
+    href="#current-block"><i>current block</i></a>; otherwise, set the
+    <var>valid</var> flag to false.
   </dl>
 
   <h3 id=consume-a-function><span class=secno>5.8. </span> <dfn
@@ -3582,6 +3609,8 @@ <h3 id=consume-a-function><span class=secno>5.8. </span> <dfn
    argument, called the <dfn id=current-argument>current argument</dfn>,
    which is initially empty.
 
+  <p> Initialize a <var>valid</var> flag to true.
+
   <p> Repeatedly consume the <a href="#next-input-token"><i>next input
    token</i></a> and process it as follows:
 
@@ -3590,8 +3619,10 @@ <h3 id=consume-a-function><span class=secno>5.8. </span> <dfn
 
    <dt>) token
 
-   <dd> Append the <a href="#current-argument"><i>current argument</i></a> to
-    the function's argument list. Return the function.
+   <dd> If the <var>valid</var> flag is true, append the <a
+    href="#current-argument"><i>current argument</i></a> to the function's
+    argument list. Return the function.
+    <p> Otherwise, return nothing.
 
    <dt>delim token with the value ","
 
@@ -3606,18 +3637,21 @@ <h3 id=consume-a-function><span class=secno>5.8. </span> <dfn
     the function's name is as <a href="#ascii-case-insensitive"><i>ASCII
     case-insensitive</i></a> match with "rect", <a
     href="#consume-a-primitive-with-the-unitless-le0"><i>consume a primitive
-    with the unitless length quirk</i></a> and append the returned value to
-    the value of the <a href="#current-argument"><i>current argument</i></a>.
-
+    with the unitless length quirk</i></a>. If anything was returned, append
+    the returned value to the value of the <a
+    href="#current-argument"><i>current argument</i></a>; otherwise, set the
+    <var>valid</var> flag to false.
     <p> Otherwise, <a href="#consume-a-primitive0"><i>consume a
-     primitive</i></a> and append the returned value to the value of the <a
-     href="#current-argument"><i>current argument</i></a>.
+     primitive</i></a>. If anything was returned, append the returned value
+     to the value of the <a href="#current-argument"><i>current
+     argument</i></a>; otherwise, set the <var>valid</var> flag to false.
 
    <dt>anything else
 
-   <dd> <a href="#consume-a-primitive0"><i>Consume a primitive</i></a> and
-    append the returned value to the value of the <a
-    href="#current-argument"><i>current argument</i></a>.
+   <dd> <a href="#consume-a-primitive0"><i>Consume a primitive</i></a>. If
+    anything was returned, append the returned value to the value of the <a
+    href="#current-argument"><i>current argument</i></a>; otherwise, set the
+    <var>valid</var> flag to false.
   </dl>
 
   <h3 id=switch-to-the-current-rules-content-mode><span class=secno>5.9.