Simplify type of Basis.tag, regarding 'class' attribute; new compatibility parsing of 'class' values given as string literals

1 files changed, 3 insertions, 2 deletions

diff --git a/doc/manual.tex b/doc/manual.tex
index 1976199d..532e0ea9 100644
--- a/doc/manual.tex
+++ b/doc/manual.tex
@@ -1954,13 +1954,13 @@ $$\begin{array}{l}
   \mt{val} \; \mt{tag} : \mt{attrsGiven} ::: \{\mt{Type}\} \to \mt{attrsAbsent} ::: \{\mt{Type}\} \to \mt{ctxOuter} ::: \{\mt{Unit}\} \to \mt{ctxInner} ::: \{\mt{Unit}\} \\
   \hspace{.1in} \to \mt{useOuter} ::: \{\mt{Type}\} \to \mt{useInner} ::: \{\mt{Type}\} \to \mt{bindOuter} ::: \{\mt{Type}\} \to \mt{bindInner} ::: \{\mt{Type}\} \\
   \hspace{.1in} \to [\mt{attrsGiven} \sim \mt{attrsAbsent}] \Rightarrow [\mt{useOuter} \sim \mt{useInner}] \Rightarrow [\mt{bindOuter} \sim \mt{bindInner}] \\
-  \hspace{.1in} \Rightarrow \mt{option} \; \mt{css\_class} \\
+  \hspace{.1in} \Rightarrow \mt{css\_class} \\
   \hspace{.1in} \to \mt{option} \; (\mt{signal} \; \mt{css\_class}) \\
   \hspace{.1in} \to \$\mt{attrsGiven} \\
   \hspace{.1in} \to \mt{tag} \; (\mt{attrsGiven} \rc \mt{attrsAbsent}) \; \mt{ctxOuter} \; \mt{ctxInner} \; \mt{useOuter} \; \mt{bindOuter} \\
   \hspace{.1in} \to \mt{xml} \; \mt{ctxInner} \; \mt{useInner} \; \mt{bindInner} \to \mt{xml} \; \mt{ctxOuter} \; (\mt{useOuter} \rc \mt{useInner}) \; (\mt{bindOuter} \rc \mt{bindInner})
 \end{array}$$
-Note that any tag may be assigned a CSS class.  This is the sole way of making use of the values produced by $\mt{style}$ declarations.  Ur/Web itself doesn't deal with the syntax or semantics of style sheets; they can be linked via URLs with \texttt{link} tags.  However, Ur/Web does make it easy to calculate upper bounds on usage of CSS classes through program analysis.  The function $\mt{Basis.classes}$ can be used to specify a list of CSS classes for a single tag.
+Note that any tag may be assigned a CSS class, or left without a class by passing $\mt{Basis.null}$ as the first value-level argument.  This is the sole way of making use of the values produced by $\mt{style}$ declarations.  Ur/Web itself doesn't deal with the syntax or semantics of style sheets; they can be linked via URLs with \texttt{link} tags.  However, Ur/Web does make it easy to calculate upper bounds on usage of CSS classes through program analysis.  The function $\mt{Basis.classes}$ can be used to specify a list of CSS classes for a single tag.
 
 Also note that two different arguments are available for setting CSS classes: the first, associated with the \texttt{class} pseudo-attribute syntactic sugar, fixes the class of a tag for the duration of the tag's life; while the second, associated with the \texttt{dynClass} pseudo-attribute, allows the class to vary over the tag's life.  See Section \ref{signals} for an introduction to the $\mt{signal}$ type family.
 
@@ -2234,6 +2234,7 @@ $$\begin{array}{rrcll}
   &&& \{e\} & \textrm{computed value} \\
 \end{array}$$
 
+Further, there is a special convenience and compatibility form for setting CSS classes of tags.  If a \cd{class} attribute has a value that is a string literal, the literal is parsed in the usual HTML way and replaced with calls to appropriate Ur/Web combinators.  Any dashes in the text are replaced with underscores to determine Ur identifiers.
 
 \section{\label{structure}The Structure of Web Applications}