Merge pull request #697 from w3c/fix-331

Align path number parsing with CSS Numbers. Fixes #331 #335

master/paths.html

@@ -881,10 +881,20 @@ <h3 id="PathDataBNF">The grammar for path data</h3>
 coordinate::= sign? number
 
 sign::= "+"|"-"
-number ::= ([0-9])+
-flag::=("0"|"1")
-comma_wsp::=(wsp+ ","? wsp*) | ("," wsp*)
-wsp ::= (#x9 | #x20 | #xA | #xC | #xD)
+
+exponent::= ("e" | "E") sign? digit+
+
+fractional-constant::= (digit* "." digit+) | digit+
+
+number::= fractional-constant exponent?
+
+flag::= ("0" | "1")
+
+comma_wsp::= (wsp+ ","? wsp*) | ("," wsp*)
+
+wsp::= (#x9 | #x20 | #xA | #xC | #xD)
+
+digit::= "0" | "1" | "2" | "3" | "4" | "5" | "6" | "7" | "8" | "9"
 </pre>
 
 <p>The processing of the EBNF must consume as much of a given
@@ -904,9 +914,18 @@ <h3 id="PathDataBNF">The grammar for path data</h3>
 that the first coordinate will be "0.6" and the second
 coordinate will be ".5".</p>
 
-<p>Note that the EBNF allows the path data string in the
-<a>'d'</a> property to be empty. This is not
-an error, instead it disables rendering of the path.
+<p class="advisement">The
+<a href="https://www.w3.org/Graphics/SVG/1.1/paths.html#PathDataBNF">grammar
+of previous specifications</a> allowed a trailing decimal point without
+any decimal digits for numbers (e.g <code>23.</code>). SVG 2 harmonizes number parsing
+with CSS [<a href="refs.html#ref-css-syntax-3">css-syntax-3</a>],
+disallowing the relaxed grammar for numbers. However, user agents may continue
+to accept numbers with trailing decimal points when parsing is unambiguous.
+Authors and authoring tools must not use the disallowed number format.</p>
+
+<p>The EBNF allows the path data string in the
+<a>'d'</a> property to be empty. An empty path data string
+disables rendering of the path.
 Rendering is also disabled when the <a>'d'</a> property
 has the value <span class='prop-value'>none</span>.</p>
 

master/refs.html

@@ -253,6 +253,15 @@ <h2 id="InformativeReferences">Informative references</h2>
       edition of CSS Shapes 2</a> is available at
     http://dev.w3.org/csswg/css-shapes-2/.
   </dd>
+  <dt id="ref-css-syntax-3" class="informref">[<a href="http://dev.w3.org/csswg/css-syntax-3/">css-syntax-3</a>]</dt>
+  <dd>
+    <cite class="w3cwd"><a href="http://dev.w3.org/csswg/css-syntax-3/">CSS Syntax Module Level 3</a></cite>,
+    Tab Atkins ed.
+    World Wide Web Consortium,  February 2014.
+    <br/>The <a href="http://dev.w3.org/csswg/css-syntax-3/">latest
+      edition of CSS Syntax 3</a> is available at
+    http://dev.w3.org/csswg/css-syntax-3/.
+  </dd>
 
   <dt id="ref-css-animations-1" class="informref">[<a href="https://www.w3.org/TR/css-animations-1/">css-animations-1</a>]</dt>
   <dd><div>Dean Jackson; David Hyatt; Chris Marrin; Sylvain Galineau; David Baron. <a href="https://www.w3.org/TR/css-animations-1/"><cite>CSS Animations</cite></a>. 30 November 2017. W3C Working Draft. URL:&nbsp;<a href="https://www.w3.org/TR/css-animations-1/">https://www.w3.org/TR/css-animations-1/</a> ED:&nbsp;<a href="https://drafts.csswg.org/css-animations/">https://drafts.csswg.org/css-animations/</a></div></dd>