# HG changeset patch
# Parent 7d4a4a7220ff5c10ffa66a74bd8d4ff796cb0e45
# User Kang-Hao (Kenny) Lu <kennyluck@csail.mit.edu>
Remove incorrect formal grammar. Tighten up some normative prose a bit

diff --git a/selectors3/Overview.src.html b/selectors3/Overview.src.html
--- a/selectors3/Overview.src.html
+++ b/selectors3/Overview.src.html
@@ -1414,23 +1414,14 @@
 For example, this allows the selectors to address every other
 row in a table, and could be used to alternate the color of paragraph
 text in a cycle of four. The <var>a</var> and <var>b</var> values must
-be integers (positive, negative, or zero). The index of the first child
-of an element is 1.
-
-<p>In addition to this, <code>:nth-child()</code> can take
-'<code>odd</code>' and '<code>even</code>' as arguments instead.
-'<code>odd</code>' has the same signification as <code>2n+1</code>,
-and '<code>even</code>' has the same signification as <code>2n</code>.
-
-<p>The argument to <code>:nth-child()</code> must match the grammar
-below, where <code>INTEGER</code> matches the token <code>[0-9]+</code>
-and the rest of the tokenization is given by the
-<a href="#lex">Lexical scanner</a> in section 10.2:
-
-<pre>nth
-  : S* [ ['-'|'+']? INTEGER? {N} [ S* ['-'|'+'] S* INTEGER ]? |
-         ['-'|'+']? INTEGER | {O}{D}{D} | {E}{V}{E}{N} ] S*
-  ;</pre>
+be integers (i.e. without a decimal dot "."). 
+The index of the first child of an element is 1.
+
+<p>In addition to this, <code>:nth-child()</code> can take a single 
+<code>IDENT</code> token representing ‘<code>odd</code>’ or
+‘<code>even</code>’ instead. ‘<code>odd</code>’ has the same signification 
+as <code>2n+1</code>, and ‘<code>even</code>’ has the same signification as 
+<code>2n</code>.
 
 <div class="example">
 <p>Examples:</p>
@@ -1446,10 +1437,8 @@
 p:nth-child(4n+4) { color: purple; }</pre>
 </div>
 
-<p>When the value <var>b</var> is preceded by a negative sign,
-the "+" character in the expression must be removed (it is
-effectively replaced by the "-" character indicating the negative
-value of <var>b</var>).</p>
+<p>If the <var>b</var> part is present, there must be one and only one sign 
+("+" or "-") after the <var>a</var><code>n</code> part.</p>
 
 <div class="example">
 <p>Examples:</p>
@@ -1493,9 +1482,9 @@
 tr:nth-child(2n) /* same */</pre>
 </div>
 
-<p>Whitespace is permitted after the "(", before the ")", and on either
-side of the "+" or "-" that separates the <var>a</var><code>n</code> and
-<var>b</var> parts when both are present.
+<p><a href="#whitespace">Whitespaces</a> and comments are permitted after the
+"(", before the ")", and on either side of the "+" or "-" that separates the
+<var>a</var><code>n</code> and <var>b</var> parts when both are present.
 
 <div class="example">
 <p>Valid Examples with white space:</p>