-*- mode: org -*-

Guile-syntax-highlight is a general-purpose syntax highlighting
library for GNU Guile.  It can parse code written in various
programming languages into a simple s-expression that can be easily
converted to HTML (via SXML) or any other format for rendering.

* Supported Languages

  - Scheme
  - XML

* Example

  #+BEGIN_SRC scheme
    (use-modules (syntax-highlight)
                 (syntax-highlight scheme)
                 (sxml simple))

    (define code
      "(define (square x) \"Return the square of X.\" (* x x))")

    ;; Get raw highlights list.
    (define highlighted-code
      (highlight scheme-highlighter code))

    ;; Convert to SXML.
    (define highlighted-sxml
      (highlights->sxml highlighted-code))

    ;; Write HTML to stdout.
    (display (sxml->xml highlighted-sxml))
    (newline)
  #+END_SRC

* Implementation details

  Very simple monadic parser combinators (purposely lacking support
  for recursive grammars currently) are used to tokenize the
  characters within a string or port and return a list consisting of
  two types of values: strings and two element tagged lists.  A tagged
  list consists of a symbol designating the type of the text (symbol,
  keyword, string literal, etc.) and a string of the text fragment
  itself.

  #+BEGIN_SRC scheme
    ((open "(")
     (special "define")
     " "
     (open "(")
     (symbol "square")
     " "
     (symbol "x")
     (close ")")
     " "
     (string "\"Return the square of X.\"")
     " "
     (open "(")
     (symbol "*")
     " "
     (symbol "x")
     " "
     (symbol "x")
     (close ")")
     (close ")"))
  #+END_SRC

  This means that the parsers are *not* intended to produce the
  abstract syntax-tree for any given language.  They are simply to
  attempt to tokenize and tag fragments of the source.  A "catch all"
  rule in each language's parser is used to deal with text that
  doesn't match any recognized syntax and simply produces an untagged
  string.

* Requirements

  - GNU Guile >= 2.0.9

* Building

  Guile-syntax-highlight uses the familiar GNU build system and
  requires GNU Make to build.

** From tarball

   After extracting the tarball, run:

   #+BEGIN_SRC sh
     ./configure
     make
     make install
   #+END_SRC

** From Git

   In addition to GNU Make, building from Git requires GNU Automake
   and Autoconf.

   #+BEGIN_SRC sh
     git clone git@dthompson.us:guile-syntax-highlight.git
     cd guile-syntax-highlight
     ./bootstrap
     ./configure
     make
     make install
   #+END_SRC

* License

  LGPLv3 or later.  See =COPYING= for the full license text.