Camlp4 predefined files

  The system provides some files, installed in Camlp4 library directory (depending on the installation, usually /usr/local/lib/camlp4: in the whole document, this directory is named camlp4-lib-dir). The provided files are:

• Parsing syntax:
  • pa_o.cmo: Objective Caml.
  • pa_r.cmo: Righteous: this is an alternative syntax for the language (chapter 5).
• Printing syntax:
  • pr_o.cmo: Pretty print with Objective Caml syntax. Add an option -l to the command line to specify a line length.
  • pr_r.cmo: Pretty print with righteous syntax. Add this option -l too.
  • pr_dump.cmo: Dump the syntax tree

Other predefined files allow to extend parsing and printing operations:

• Parsing extensions:
  • pa_oop.cmo: (to be loaded after ``pa_o.cmo'') Parsers and streams, with Objective Caml syntax, without code optimization, corresponding to what is internally generated by the Objective Caml compiler.
  • pa_op.cmo: (to be loaded after ``pa_o.cmo'') Parsers and streams, with Objective Caml syntax, with code optimization.
  • pa_rp.cmo: (to be loaded after ``pa_r.cmo'') Parsers and streams, with righteous syntax and code optimization.
  • pa_extend.cmo: (to be loaded either after ``pa_o.cmo'' or ``pa_r.cmo'') Syntax extensions for the Camlp4 grammar system (Chapter 3).
  • pa_ifdef.cmo: add ifdef statement like in C (conditional compilation), in expressions or structure items. Add the options -D and -U to the camlp4 command line. To define the symbol FOO, either use ``-DFOO'' in the camlp4 command line, e.g.:

            camlp4o pa_ifdef.cmo -DFOO file.ml
    

    or make a file, e.g. ``foo.ml'', holding

            Pa_ifdef.define "FOO";;
    

    compile it and load its corresponding object file:

            camlp4o pa_ifdef.cmo ./foo.cmo file.ml
    

    To undefine the symbol FOO, use either ``-UFOO'' or the function ``Pa_ifdef.undef''. The statement ``ifdef'' can be used in a place of a struture item or an expression: in this last case, ``else'' is required:

            ifdef FOO then type t = A of int;;
            let f x = ifdef FOO then x + 1 else x - 1;;
    

  • pa_ru.cmo: (to be loaded after ``pa_r.cmo'' only) Add type constraints of type unit inside sequences.
• Printing extensions:
  • pr_op.cmo: Try to rebuilt parsers and streams in Objective Caml syntax.
  • pr_rp.cmo: Try to rebuilt parsers and streams in righteous syntax.
  • pr_extend.cmo: Try to rebuilt EXTEND instructions.

Some shortcut commands are provided:

• ``camlp4o'' is equivalent to:

          camlp4 pa_o.cmo pa_op.cmo pr_dump.cmo
  

• ``camlp4r'' is equivalent to:

          camlp4 pa_r.cmo pa_rp.cmo pr_dump.cmo