Super Haddock (was Re: Literate Programming)

[Magnus Carlsson]

Johannes Waldmann writes:
 > > On Friday 25 April 2003 09:09, Ketil Z. Malde wrote:
 >=20
 > > > I'm not sure I would like this.  I guess I'm one of (the apparen=
tly
 > > > very few?) who are using LaTeX lhs style (using \begin/\end{code=
}).
 >=20
 > I don't use .lhs normally but I would love to see some "active lhs",=

 > that is, text containing Haskell expressions that actually
 > get evaluated when (or before) typsetting.
 > (Mathematica has this, and I'm sure some other systems do it also.)
 >=20
 > Preferably accompanied by a class (like Show)=20
 > producing formatted output - perhaps LaTeX, perhaps HTML.
 > (Example application: I'm writing a graph theory text,
 > and I want to embed pictures that are produced by a Haskell program)=

 >=20
 > I once built a similar beast (for active literate programming
 > in a domain specific language - not Haskell)=20
 > (but the implementation was done in Haskell, of course)
 > to typeset my PhD thesis.

Thomas Hallgren and I wrote a little system called HacWrite similar to
what you describe, for producing our thesis.  (Yes, it was
procrastination! :-)

Basically, it was Haskell, enhanced with a new literal for markup
text, within =ABfunny quotation marks like this=BB.  Within the text, o=
ne
could again escape to Haskell by using curly brackets.  We had
backends generating LaTeX and HTML.  For example, the HacWrite source

  section =ABCongruence rules=BB $do

    =ABFollowing the style of {cite"berry:chemical"}, we define a
    bunch of congruence rules which can be used freely to find
    reaction rules to apply.=BB

    eqtable eqop
      [ (s+t        , t+s             ,=ABCommutativity of {parop}=BB)
      , (p(s+t)+u   , s+p(t+u)        ,=ABAssociativity of {parop}=BB)
      , (p(s<<t)<<u , s<<p(t<<u)      ,=ABAssociativity of {serop}=BB)
      , (s<<p(t!u)  , p(s<=B7t)<<u      ,=ABInternal communication in
                                       {serop}=BB)
      , (p(s+t)<=B7u  , p(s<=B7u)+p(t<=B7u) ,=ABDistributivity of
                                       {feedop} over {parop}=BB)
      , (p(s!t)<=B7u  , s!p(t<=B7u)       ,=ABOutput from {feedop}=BB)
      , (p(s!t)<<u  , s!p(t<<u)       ,=ABOutput from {serop}=BB)
      , (p(x?s)<=B7t  , s//(t,x)        ,=ABSubstitution=BB)
      ]

produced the (moderately nice-looking) HTML code at=20

  http://www.cs.chalmers.se/~hallgren/Thesis/future-work.html#43.1.2

and the hard copy (via LaTeX) on page 241 in

  http://www.cs.chalmers.se/~hallgren/Thesis/fudgets_thesis_color.ps.gz=


Although HacWrite was somewhat primitive, it was delightful to be able
to define and use Haskell functions instead of LaTeX macros.

I wonder how many typesetting systems like these there are out there,
written by PhD students...

Cheers,
/M