fixes #776 (#1033)

Author: martin-henz

xml/chapter1/section1/subsection6.xml

@@ -231,7 +231,9 @@ abs(-5);
         <META>alternative-expression</META> and returns its value as the value of the
 	conditional.<FOOTNOTE>
 	<INDEX>conditional expression<SUBINDEX>non-boolean value as predicate</SUBINDEX></INDEX>
-	Conditionals in full JavaScript accept any value, not just a boolean, as the result of evaluating
+	Conditionals
+	<LABEL NAME="foot:any-value-as-predicate"/>
+	in full JavaScript accept any value, not just a boolean, as the result of evaluating
 	the <META>predicate</META> expression (see footnote<SPACE/><REF NAME="foot:truthy"/>
 	in section<SPACE/><REF NAME="sec:eval-data-structures"/> for details). The programs in this book
 	use only boolean values as predicates of conditionals.
@@ -591,8 +593,10 @@ $\vdots$
             <INDEX>evaluation<SUBINDEX>of <JAVASCRIPTINLINE>&amp;&amp;</JAVASCRIPTINLINE><ORDER>of ;1</ORDER></SUBINDEX><FRAGILE/></INDEX>
 	    <EM>logical conjunction</EM>, meaning roughly 
 	    the same as the English word <QUOTE>and.</QUOTE>
-	    This syntactic form is syntactic sugar<FOOTNOTE>
-            Syntactic forms that are simply convenient
+	    We assume<FOOTNOTE>This assumption is justified by the restriction mentioned
+	    in footnote<SPACE/><REF NAME="foot:any-value-as-predicate"/>. Full JavaScript
+	    needs to consider the case where the result of evaluating <META>expression</META><LATEXINLINE>$_1$</LATEXINLINE> is neither true nor false.</FOOTNOTE> this syntactic form to be syntactic
+	    sugar<FOOTNOTE>Syntactic forms that are simply convenient
             alternative surface structures for things that can be written in more
             uniform ways are sometimes called <EM>syntactic sugar</EM>, to use a
             phrase coined by 
@@ -617,7 +621,7 @@ $\vdots$
             <INDEX>evaluation<SUBINDEX>of {\tt "|"|}<ORDER>of ;2</ORDER></SUBINDEX><FRAGILE/></INDEX>
 	    <EM>logical disjunction</EM>, meaning roughly
 	    the same as the English word <QUOTE>or.</QUOTE>
-	    This syntactic form is syntactic sugar for<BR/>
+	    We assume this syntactic form to be syntactic sugar for<BR/>
 	    <META>expression</META><LATEXINLINE>$_1$</LATEXINLINE> <JAVASCRIPTINLINE>?</JAVASCRIPTINLINE>
 	    <JAVASCRIPTINLINE>true</JAVASCRIPTINLINE> <JAVASCRIPTINLINE>:</JAVASCRIPTINLINE>
 	    <META>expression</META><LATEXINLINE>$_2$</LATEXINLINE>.