add buffer virtual prop defineProperty() limitation to guide, section ids for type sections

website/guide/stacktypes.html

@@ -17,7 +17,7 @@
 </table>
 </div>
 
-<h2>Memory allocations</h2>
+<h2 id="type-memory-allocations">Memory allocations</h2>
 
 <p>The following stack types involve additional heap allocations:</p>
 
@@ -37,7 +37,7 @@
 type in Ecmascript, they are a heap allocated type from a memory allocation
 viewpoint.</p>
 
-<h2>Pointer stability</h2>
+<h2 id="type-pointer-stability">Pointer stability</h2>
 
 <p>Heap objects allocated by Duktape have stable pointers: the objects are
 not relocated in memory while they are reachable from a garbage collection
@@ -65,7 +65,7 @@ area across a buffer resize, and it's probably best not to hold a pointer
 after a Duktape/C function returns (how would you reliably know when the
 buffer is resized?).</p>
 
-<h2>Type masks</h2>
+<h2 id="type-masks">Type masks</h2>
 
 <p>Type masks allows calling code to easily check whether a type belongs to
 a certain type set.  For instance, to check that a certain stack value is
@@ -105,12 +105,12 @@ if (t == DUK_TYPE_NUMBER || t == DUK_TYPE_STRING || t == DUK_TYPE_OBJECT) {
 }
 </pre>
 
-<h2>None</h2>
+<h2 id="type-none">None</h2>
 
 <p>The <b>none</b> type is not actually a type but is used in the API to
 indicate that a value does not exist, a stack index is invalid, etc.</p>
 
-<h2>Undefined</h2>
+<h2 id="type-undefined">Undefined</h2>
 
 <p>The <b>undefined</b> type maps to Ecmascript <code>undefined</code>, which is
 distinguished from a <code>null</code>.</p>
@@ -118,11 +118,11 @@ distinguished from a <code>null</code>.</p>
 <p>Values read from outside the active value stack range read back as
 <b>undefined</b>.</p>
 
-<h2>Null</h2>
+<h2 id="type-null">Null</h2>
 
 <p>The <b>null</b> type maps to Ecmascript <code>null</code>.</p>
 
-<h2>Boolean</h2>
+<h2 id="type-boolean">Boolean</h2>
 
 <p>The <b>boolean</b> type is represented in the C API as an integer: zero for false,
 and non-zero for true.</p>
@@ -151,7 +151,7 @@ int bitmask = (duk_get_boolean(ctx, -3) ? (1 &lt;&lt; 2) : 0) |
               (duk_get_boolean(ctx, -1) ? 1 : 0);
 </pre>
 
-<h2>Number</h2>
+<h2 id="type-number">Number</h2>
 
 <p>The <b>number</b> type is an IEEE double, including +/- Infinity and NaN values.
 Zero sign is also preserved.  An IEEE double represents all integers up to 53 bits
@@ -163,7 +163,7 @@ packed values), NaN values in the Duktape API are normalized.  Concretely, if yo
 push a certain NaN value to the value stack, another (normalized) NaN value may
 come out.  Don't rely on NaNs preserving their exact form.</p>
 
-<h2>String</h2>
+<h2 id="type-string">String</h2>
 
 <p>The <b>string</b> type is a raw byte sequence of a certain length which may
 contain internal NUL (0x00) values.  Strings are always automatically NUL
@@ -247,7 +247,7 @@ continuation bytes are marked with "C" (indicating the bit sequence 10xxxxxx):</
 the leading byte will be <code>0xFE</code> which conflicts with Unicode byte order
 marker encoding.  This is not a practical concern in Duktape's internal use.</p>
 
-<h2>Object</h2>
+<h2 id="type-object">Object</h2>
 
 <p>The <b>object</b> type includes Ecmascript objects and arrays, functions, and
 threads (coroutines).  In other words, anything with properties is an object.
@@ -256,7 +256,7 @@ Properties are key-value pairs with a string key and an arbitrary value
 
 <p>Objects may participate in garbage collection finalization.</p>
 
-<h2>Buffer</h2>
+<h2 id="type-buffer">Buffer</h2>
 
 <p>The <b>buffer</b> type is a raw buffer for user data of either fixed or dynamic
 size.  The size of a fixed buffer is given at its creation, and fixed buffers
@@ -289,21 +289,22 @@ property is read-only at the moment (so you can't resize a string by assigning
 to the length property).  These properties are available for both plain buffer
 values and buffer object values.</p>
 
-<div class="note">
-Because the value written to a buffer index is number coerced, assigning
+<p>A few notes:</p>
+<ul>
+<li>Because the value written to a buffer index is number coerced, assigning
 a one-character value does not work as often expected.  For instance, 
 <code>buf[123] = 'x'</code> causes zero to be written to the buffer, as
 ToNumber('x') = 0.  For clarity, you should only assign number values,
-e.g. <code>buf[123] = 0x78</code>.
-</div>
-
-<div class="note">
-There is a fast path for reading and writing numeric indices of plain buffer
+e.g. <code>buf[123] = 0x78</code>.</li>
+<li>There is a fast path for reading and writing numeric indices of plain buffer
 values, e.g. <code>x = buf[123]</code> or <code>buf[123] = x</code>.  This
-fast path is not active when the base value is a Buffer object.
-</div>
+fast path is not active when the base value is a Buffer object.</li>
+<li>Buffer virtual properties are not currently implemented in
+<code>defineProperty()</code>, so you can't write to buffer indices or
+buffer <code>length</code> with <code>defineProperty()</code> now.</li>
+</ul>
 
-<h2>Pointer</h2>
+<h2 id="type-pointer">Pointer</h2>
 
 <p>The <b>pointer</b> type is a raw, uninterpreted C pointer, essentially
 a <code>void *</code>.  Pointers can be used to point to native objects (memory