I applaud the intention of the Haskerl group to make the use of Haskell
easier and, in the same spirit, I would like to suggest some further
extensions to make "literate" programming easier.
Most Haskell users (and certainly all Haskell compiler writers) also
use LaTeX, so I suggest that literate programming should be made easier
by integrating some LaTeX features into Haskell to enable automatic
pretty-printing of programs.
My first suggestion is that lists could be delimited by the itemize
environment e.g.
\begin{itemize}
first element,
second element,
long and involved third element,
fourth element
\end{itemize}
The printed version of this list would be of the form:
[first element,
second element,
long and involved
third element,
fourth element]
so indentation would be automatically taken care of.
Arrays could be similarly defined using the enumerate environment, so:
\begin{enumerate}
first, second, third
\end{enumerate}
would print as:
array (1,3) [1 := first,
2 := second,
3 := third]
This requires a little intelligence to work out the upper array bound,
but that is not hard.
The possibilities for mathematical programming are endless. For example:
\sum_{i=0}^{n} x_{i}
would be the sum of the first n+1 elements of the list x, and would be
printed using the sigma notation, which is much easier to read than the
Haskell equivalent.
It goes without saying that Haskerlatex (as I have dubbed it) would
print all variable names in italic, keywords in bold and so forth to
further aid the program reader.
I could go on and on about the advantages of these extensions, but I will
stop now as I would like the Haskerl group to have time to consider them
soon, as I presume it has a strictly limited lifetime.
Nick North
National Physical Laboratory
