Including files from ml-lex and -yacc

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5 total messages Started by Urban Engberg Tue, 10 Nov 1992 14:28

#560

Author: Urban Engberg
Date: Tue, 10 Nov 1992 14:28

29 lines
1567 bytes

In the language of a parser I am writing I want to use the parser
directive %Include <filename> meaning that the file <filename> is to
be included in the parsed file just as if its contents were actually
put there.  I would like to do this inside ml-lex and/or -yacc, which
means that I have to do some operations on the streams that are
generated in the lexer and passed on to the parser.  Has anyone done
this?  How?

This is how I construct the parser:

structure PreParser : PREPARSER =
  struct
    val parse = fn s =>
      let val dev    = open_in s
          val stream = PreParserParser.makeLexer (fn i => input(dev, i))
          val _      = PreParserLex.UserDeclarations.pos := (1, 0)
          val error  = fn (e, (oldline:int, oldchar:int),
			      (newline:int, newchar:int)) => 
            		  output(std_out, "...")
      in PreParserParser.parse(30, stream, error, ()) before close_in dev
      end
  end


--
Urban Engberg					Computer Science Department
urban@daimi.aau.dk				Aarhus University
Phn: +45 86 20 27 11 - 50 91			Ny Munkegade
Fax: +45 86 13 57 25				DK-8000 Aarhus C  --  DENMARK

Re: Including files from ml-lex and -yacc

#914

Author: John Farrell
Date: Mon, 16 Nov 1992 06:33

11 lines
1016 bytes

In <1992Nov10.142821.8095@daimi.aau.dk> urban@daimi.aau.dk (Urban Engberg) writes:
>In the language of a parser I am writing I want to use the parser
>directive %Include <filename> meaning that the file <filename> is to
>be included in the parsed file just as if its contents were actually
>put there.

  I thought the standard way to do this was to use the same compiler
directives as C does, then use the C preprocessor :-). It's a hack, I know,
but it provides a well-known set of functions at very low cost.

John

Re: Including files from ml-lex and -yacc

#916

Author: Andrew Koenig
Date: Mon, 16 Nov 1992 18:01

10 lines
1053 bytes

In article <farrell.721895635@coral> farrell@coral.cs.jcu.edu.au (John Farrell) writes:

>   I thought the standard way to do this was to use the same compiler
> directives as C does, then use the C preprocessor :-). It's a hack, I know,
> but it provides a well-known set of functions at very low cost.

Just make sure you don't utter the names of any macros in your ML comments.
-- 
				--Andrew Koenig
				  ark@europa.att.com

Re: Including files from ml-lex and -yacc

#924

Author: Patrick Miller
Date: Tue, 17 Nov 1992 16:57

21 lines
1482 bytes

In article <farrell.721895635@coral>, farrell@coral.cs.jcu.edu.au (John Farrell) writes:
|> >directive %Include <filename> meaning that the file <filename> is to
|> ...

|>   I thought the standard way to do this was to use the same compiler
|> directives as C does, then use the C preprocessor :-). It's a hack, I know,
|> but it provides a well-known set of functions at very low cost.

One has to be careful how this is done.  Remember that C preprocessors
have varying awareness of comment characters, etc...   The following
was causing the Sisal preprocessor (a CPP hack as described) to bomb.
The % is a comment character.

		for initial			% Can't do it too much

The problem was that Sisal uses Mark-to-endofline comments.  The CPP
was getting confused over the single quote without matching end quote!

-- 
Pat Miller                            I have many opinions, but they
patmiller@llnl.gov                      generally aren't humble ones

Re: Including files from ml-lex and -yacc

#925

Author: Urban Engberg
Date: Wed, 18 Nov 1992 09:50

7 lines
965 bytes

Thanks for all advice.  David Tarditi sent me some ml-code
implementing a stack of lexers, doing the job brilliantly.   Whenever
lex meets an include directive, it runs a new lexer on the include
file and pushes itself on the stack etc.  I would be happy to
distribute it to whoever is interested.

  Urban

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