+++ /dev/null
-\section{External specification}
-
-The program is to be run in UNIX by typing {\tt pphs} followed by the
-filename containing the Haskell code requiring to be typeset. This will
-produce the \LaTeX\ code to stdout. If there is some error,
-a suitable error message is to be printed to stderr. The user may, if
-desired, direct the output to another file by typing {\tt pphs infilename > outfilename}.
-In this case, any error messages must still go to the screen and not the file.
-
-The input filename may be given in its entirety or the {\tt .hs} extension may be omitted.
-In the case where there are two files with the same name, except that one has the
-{\tt .hs} extension, to run the program on the file with the extension to its name
-the complete filename will be typed.
-
-The output will consist of the \LaTeX\ code to produce the typeset Haskell
-code. As this is to be made easily insertable into another \LaTeX\ document, the output
-will not contain any header information such as declarations or definitions. These,
-however, can
-be contained in a style file which the user will include in their main document.
-
-Keywords and identifiers are to be distinguished in the result as typeset.
-The default for keywords is to be boldface and for identifiers italics.
-Numbers not forming part of an identifier are to be in roman by default
-while math is to be used where appropriate.
-
-Haskell uses ASCII characters and combinations of ASCII characters
-to substitute for mathematical characters not present on the
-keyboard. Where this happens, the program is to replace the ASCII character(s)
-with the corresponding mathematical character using the special \LaTeX\ commands
-to generate them. The single characters are:
-\begin{quote}
-\begin{tabular}[t]{@{}cc@{}}
-Haskell & Math\\
-{\tt *} & $\times$
-\end{tabular}
-\end{quote}
-The double characters are:
-\begin{quote}
-\begin{tabular}[t]{@{}cc@{}}
-Haskell & Math\\
-{\tt ++} & {\hbox{$+\mkern-7.5mu+$}}\\
-{\tt :+} & {:}{+}\\
-{\tt <=} & $\leq$\\
-{\tt >=} & $\geq$\\
-{\tt <-} & $\leftarrow$\\
-{\tt ->} & $\rightarrow$\\
-{\tt =>} & $\Rightarrow$
-\end{tabular}
-\end{quote}
-
-The \LaTeX\ system uses special characters to aid with the typesetting.
-They are:
-\begin{quote}
-\(\#\ \$\ \%\ \&\ \char'176\ \_\ \char'136\ \hbox{$\setminus$}\ \hbox{$\cal \char'146\ \char'147$}\)
-\end{quote}
-These characters may
-appear in the input, so the program must generate the correct \LaTeX\ code to
-print them and
-avoid having them mess up the typesetting process.
-
-As the output when typeset must have the same layout as the input, the program
-must get the linebreaks and indentation right. As \LaTeX\ is primarily designed for normal
-text, it would ignore the linebreaks and indentation in the Haskell file. Therefore
-the program must insert them using the correct typesetting commands. In the case of
-linebreaks it must recognise where these occur, but for indentation it must also work out
-how much space needs to be inserted.
-
-There are two types of indentation in Haskell programs: left-hand and internal.
-For the former, the program must work out what the start of the line is aligned
-under in the input file. It then has to calculate how much space is required
-to get the line of text to line up with this in the output once typeset.
-Take, for instance, the following Haskell example input:
-\begin{quote}
-\begin{verbatim}
-foobar a b = c
- where
- c = (a, b)
-\end{verbatim}
-\end{quote}
-Notice that the {\tt w} of {\tt where} on the second line lines up
-under the {\tt =} on
-the first line. Similarly, the {\tt c} on the third line is aligned under the
-final letter of {\tt where} on the second line. The result as typeset must
-get the indentation correct like this:
-\begin{quote}
-\begin{tabbing}
-foobar a b = c\\
-\newbox\foo
-{\setbox\foo\hbox{foobar a b }\hskip\wd\foo}where\\
-{\setbox\foo\hbox{foobar a b wher}\hskip\wd\foo}c = (a, b)
-\end{tabbing}
-\end{quote}
-
-For internal indentation, the program must first recognise where it has
-occurred. It must then insert the correct amount of space to get alignment
-in the output. As \LaTeX\ uses variable-width characters, extra space
-may be needed in lines preceding a line within an internal alignment section.
-This is necessary if a lower line which
-aligns in the input file is longer up to the alignment point,
-due to the variable-width characters, than its predecessors
-once it has been properly typeset. For example:
-\begin{quote}
-\begin{verbatim}
-lilli :: a
-wmwm :: b
-\end{verbatim}
-\end{quote}
-becomes
-\begin{quote}
-\begin{tabular}[t]{@{}l@{\ }c@{\ }l}
-lilli & :: & a\\
-wmwm & :: & b\\
-\end{tabular}
-\end{quote}
-Notice how {\tt lilli} is longer than {\tt wmwm} in the input file style
-using fixed-width font but shorter when using the variable-width font
-of the typeset output.
projects / ghc-hetmet.git / blobdiff