-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Isaac Dupree wrote:
we don't have standards-quality wording yet
Okay, here's a first attempt at formalizing it. It's really messy yet, and doesn't incorporate narrative material from the Haskell 98 literate comments section yet. Feedback so far? Literate programs are interpreted as a series of lines that are parsed, and each line is transformed to another line that is part of the program text. Here are some (String -> Bool) to test lines during parsing. BIRDPROG = begins with ">" BEGIN = "\begin{code}" ++ (all isSpace) END = "\end{code}" ++ (all isSpace) TEXPROG = doesn't begin with "\begin{code}" or "\end{code}" BLANKLINE = all isSpace COMMENTLINE = doesn't begin with ">", "\begin{code}" or "\end{code}" and not all isSpace BORINGLINE = BLANKLINE | COMMENTLINE = doesn't begin with ">", "\begin{code}" or "\end{code}" If we want to incorporate the "no comment lines adjacent to program lines" into the syntax here, we have comment = one or more COMMENTLINE birdprog = one or more BIRDPROG birdOrComment = birdprog | comment texprog = BEGIN (zero or more TEXPROG) END notBirdOrComment = BLANKLINE | texprog file = (zero or more notBirdOrComment) birdOrComment (zero or more ((one or more notBirdOrComment) birdOrComment)) (zero or more notBirdOrComment) which is a little ugly compared to file = zero or more (BORINGLINE | BIRDPROG | texprog) texprog = BEGIN (zero or more TEXPROG) END (Neither one expresses the requirement (not explicitly present in Haskell 98) that there must be at least one actual program line in the result. Of course, if there isn't such a requirement, the file would mean "module Main(main) where {}" which is in error anyway.) Lines judged to be BIRDPROG have the initial ">" replaced with a " ". Lines judged to be TEXPROG are retained intact. All other lines are reduced to emptiness. It is not advisable to have a single lexical unit ("lexeme" (which only includes "gap" for these purposes) or "ncomment" --- references from Haskell98 section 9.2 Lexical Syntax) that crosses a line that was a COMMENTLINE. (or, unadvisable to cross ANY line other than BIRDPROG and TEXPROG, because doing so is just weird anyway.) Isaac -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.3 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iD8DBQFF6a3zHgcxvIWYTTURAiqtAKCAXtNFueCxsTRNJpuSYuPL+6On4wCeJNQV Teswf08Pr0senEaeNRNvJsw= =ZiJL -----END PGP SIGNATURE-----