elaborate upon functional dependency!

diff --git a/methods.mtask.tex b/methods.mtask.tex
index 5bdbbb1..4a71394 100644 (file)
--- a/methods.mtask.tex
+++ b/methods.mtask.tex
@@ -68,15 +68,23 @@ as \emph{while} or \emph{for} constructions. The main control flow operators
 are the sequence operator and the \emph{if} statement. Both are shown in
 Listing~\ref{lst:control}. The first class of \emph{If} statements describes
 the regular \emph{if} statement. The expressions given can have any role. The
-functional dependency\todo{explain} on \CI{s} determines the return type of the
-statement.  The sequence operator is very straightforward and just ties the two
-expressions together in sequence.
+functional dependency on \CI{s} determines the return type of the
+statement. The listing includes examples of implementations that illustrate
+this dependency.
+
+The sequence operator is very straightforward and just ties
+the two expressions together in sequence.
 
 \begin{lstlisting}[%
        language=Clean,label={lst:control},caption={Control flow operators}]
 class If v q r ~s where
   If :: (v Bool p) (v t q) (v t r) -> v t s | ...
 
+instance If Code Stmt Stmt Stmt
+instance If Code e    Stmt Stmt
+instance If Code Stmt e    Stmt
+instance If Code x    y    Expr
+
 class seq v where
   (:.) infixr 0 :: (v t p) (v u q) -> v u Stmt | ...
 \end{lstlisting}