on* handlers

1 files changed, 13 insertions, 1 deletions

diff --git a/doc/manual.tex b/doc/manual.tex
index 7ecbfafd..9acbc1c5 100644
--- a/doc/manual.tex
+++ b/doc/manual.tex
@@ -1621,10 +1621,13 @@ There is a function for producing an XML tree with a particular tag at its root.
 $$\begin{array}{l}
   \mt{val} \; \mt{tag} : \mt{attrsGiven} ::: \{\mt{Type}\} \to \mt{attrsAbsent} ::: \{\mt{Type}\} \to \mt{ctxOuter} ::: \{\mt{Unit}\} \to \mt{ctxInner} ::: \{\mt{Unit}\} \\
   \hspace{.1in} \to \mt{useOuter} ::: \{\mt{Type}\} \to \mt{useInner} ::: \{\mt{Type}\} \to \mt{bindOuter} ::: \{\mt{Type}\} \to \mt{bindInner} ::: \{\mt{Type}\} \\
-  \hspace{.1in} \to \lambda [\mt{attrsGiven} \sim \mt{attrsAbsent}] \; [\mt{useOuter} \sim \mt{useInner}] \; [\mt{bindOuter} \sim \mt{bindInner}] \Rightarrow \$\mt{attrsGiven} \\
+  \hspace{.1in} \to \lambda [\mt{attrsGiven} \sim \mt{attrsAbsent}] \; [\mt{useOuter} \sim \mt{useInner}] \; [\mt{bindOuter} \sim \mt{bindInner}] \\
+  \hspace{.1in} \Rightarrow \mt{option} \; \mt{css\_class} \\
+  \hspace{.1in} \to \$\mt{attrsGiven} \\
   \hspace{.1in} \to \mt{tag} \; (\mt{attrsGiven} \rc \mt{attrsAbsent}) \; \mt{ctxOuter} \; \mt{ctxInner} \; \mt{useOuter} \; \mt{bindOuter} \\
   \hspace{.1in} \to \mt{xml} \; \mt{ctxInner} \; \mt{useInner} \; \mt{bindInner} \to \mt{xml} \; \mt{ctxOuter} \; (\mt{useOuter} \rc \mt{useInner}) \; (\mt{bindOuter} \rc \mt{bindInner})
 \end{array}$$
+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.
 
 Two XML fragments may be concatenated.
 $$\begin{array}{l}
@@ -1668,6 +1671,15 @@ $$\begin{array}{l}
   \mt{val} \; \mt{sleep} : \mt{int} \to \mt{transaction} \; \mt{unit}
 \end{array}$$
 
+A few functions are available to registers callbacks for particular error events.  Respectively, they are triggered on calls to $\mt{error}$, uncaught JavaScript exceptions, failure of remote procedure calls, the severance of the connection serving asynchronous messages, or the occurrence of some other error with that connection.  If no handlers are registered for a kind of error, then occurrences of that error are ignored silently.
+$$\begin{array}{l}
+  \mt{val} \; \mt{onError} : (\mt{xbody} \to \mt{transaction} \; \mt{unit}) \to \mt{transaction} \; \mt{unit} \\
+  \mt{val} \; \mt{onFail} : (\mt{string} \to \mt{transaction} \; \mt{unit}) \to \mt{transaction} \; \mt{unit} \\
+  \mt{val} \; \mt{onConnectFail} : \mt{transaction} \; \mt{unit} \to \mt{transaction} \; \mt{unit} \\
+  \mt{val} \; \mt{onDisconnect} : \mt{transaction} \; \mt{unit} \to \mt{transaction} \; \mt{unit} \\
+  \mt{val} \; \mt{onServerError} : (\mt{string} \to \mt{transaction} \; \mt{unit}) \to \mt{transaction} \; \mt{unit}
+\end{array}$$
+
 \subsubsection{Functional-Reactive Page Generation}
 
 Most approaches to ``AJAX''-style coding involve imperative manipulation of the DOM tree representing an HTML document's structure.  Ur/Web follows the \emph{functional-reactive} approach instead.  Programs may allocate mutable \emph{sources} of arbitrary types, and an HTML page is effectively a pure function over the latest values of the sources.  The page is not mutated directly, but rather it changes automatically as the sources are mutated.