to-srfi

#!/usr/bin/perl

# to-srfi - make a Java ".g" file ready for insertion into a Scheme SRFI.
# It filters stdin to translate its action rules into Scheme and
# escape HTML-special names.
# Intended for use on sweet.g, so that we can write in Java (for ANTLR)
# and show Scheme syntax to everyone else.

# This is a very simplistic textual translation.
# This approach does not work in general, but since the input is
# simple, stylized, and controlled by us, it works just fine in this case.
# This presumes that lines with action rules have a "{" or "}" on the line.


$translate = 1;
$include_in_srfi = 0;

while (<>) {
  if (/PARSER SECTION/) {
    $translate = 1;
  }
  if (/INCLUDE IN SRFI/) {
    $include_in_srfi = 1;
  }
  if (/STOP INCLUDING IN SRFI/) {
    $include_in_srfi = 0;
  }
  if ($translate && /[{}]/) {

    s/([a-z0-9_]+)\(\)/(\1)/g;
    s/([a-z0-9_]+)\(/(\1 /g;

    s/{ ?\$v ?= ?/{/g;
    s/ ?; ?}/}/g;
    s/\.v\b//g;
    s/\bnull\b/'()/g;

    s/"vector"/'vector/;
    s/"bytevector"/'bytevector/;
    s/"quote"/'quote/;
    s/"quasiquote"/'quasiquote/;
    s/"unquote-splicing"/'unquote-splicing/;
    s/"unquote"/'unquote/;

    # Serious hack to remove commas as parameter separators; only do this
    # if it appears commas are being used as separators.
    s/, / /g  if ( /\(.*,.*\)/ ) ;

    # Special case.
    s/\(list "."\)/(list '.)/g;
    s/\{"."\}/{'.}/g;
    s/{greedy=false}/{greedy=false;}/g;
  }

  s/ returns \[Object v\]//;

  s/\&/&amp;/g;
  s/</&lt;/g;
  s/>/&gt;/g;

  s/\r//g;

  if ($include_in_srfi && (! /INCLUDE IN SRFI/)) {
    print;
  }
}