Index: 10_forge.html
===================================================================
--- 10_forge.html	(revision 8119)
+++ 10_forge.html	(revision 8120)
@@ -7,6 +7,8 @@
 way for describing attribute transformations in attributes (e.g. in a
 library symbol) during compilation.
 
+<h2> 10.1. Unconditinal forge </h1>
+
 <p>{imp10:1}
 The forge plugin works from the array attribute <i>forge</i>, which is
 taken as an ordered list of atomic steps to execute on attributes. For
@@ -57,9 +59,61 @@
 	<li> <b>darr</b>: if destination is an array, the source (or each element of the source, if it's an array) is combined into the destination array. Fails if source is array and destination is scalar.
 </ul>
 
+<h2> 10.1. Conditinal forge </h2>
+<p>{imp10:8}
+Attributes whose key start with <b>forge-if/</b> are used for conditional
+execution of forge. The remainder of the attribute key is an arbitrary
+identifier, for example forge-if/dnp is commonly used for setting a DNP
+(do-not-populate) attribute depending on the current view and/or stances.
 
+<p>{imp10:9} The attribute is an array; the first line contains
+the condition; the rest of the lines contain the same forge operations
+as the unconditional <i>forge</i> attribute.
 
+<p>{imp10:10} The condition is an expression in the usual infix form.
+There are three data types supported:
+<ul>
+	<li> integer: a sequence of digits (decimal number, not larger than 2^31-1)
+	<li> string literal: a sequence of characters enclosed in double quotes; a double quote can be added using the usual \" form, and \\ is taken as a single backslash
+	<li> constant: an id or id.id that is going to be substituted with the value of the named constant; the value is always a string
+</ul>
 
+<p>{imp10:11} The following binary operators are defined for strings (where each
+oparand is a string literal or a constant):
+<ul>
+	<li> <b>str == str</b> is 1 if the two strings match (case sensitive), 0 otherwise; the result is an integer
+	<li> <b>str != str</b> is 0 if the two strings match (case sensitive), 1 otherwise; the result is an integer
+<ul>
 
 
+<p>{imp10:12} The following binary operators are defined for integers, with
+their usual meaning and precedence:
+<ul>
+	<li> == means equal
+	<li> != means not-equal
+	<li> &lt;
+	<li> &gt;
+	<li> &lt;=
+	<li> &gt;=
+	<li> &amp;&amp; means logic "and"
+	<li> || means logic "or"
+	<li> -, +, *, / are the usual subtract, add, multiply, divide
+	<li> % is the remainder of an integer division
+</ul>
 
+<p>{imp10:13} The following non-binary operators are defined for integers, with
+their usual meaning and precedence:
+<ul>
+	<li> ! is the unary "not" operator
+	<li> - is the unary minus
+</ul>
+
+<p>{imp10:14} Parenthesis affects the precedence the usual way.
+
+
+<h2 id="des10.2">> 10.2. Stances for conditinal forge </h2>
+
+TODO
+
+
+