How to convert Datalog to Mangle?

[ceving]

Has Mangle anything better than the following to convert Datalog syntax to Mangle syntax?

#! /usr/bin/perl

use strict;
use warnings;

while (<>) {
  chomp;
  next if /^\s*$/;
  my $comment;
  if (/([^%]*)% (.*)/) {
    $_ = $1;
    $comment = $2;
    $comment =~ s/^\?- /? /;
  }
  s/(\s*):-(\s*)/$1⟸$2/g;
  s/\b([a-z][0-9a-zA-Z_]+)\b(?!\()/"$1"/g;
  
  print $_, ($comment ? '# '.$comment : ''), "\n";
}

[burakemir]

Can you specify what you mean by Datalog syntax? I am not aware of any claim towards being a standard.

Mangle datalog makes some choices (see grammar):

• predicate names are lower case (snake case)
• variable names are upper case
• for rules with a body, you can use either :- or ⟸, whatever you prefer.
• a rule without a body, one writes just the head atom followed by .
• line comments are written #

... and then more can be said about negation using ! (very much prolog incompatible), and numbers, strings, multi-line strings, byte strings.
There is a bit of user documentation https://mangle.readthedocs.io/en/latest/basictypes.html

I introduced ⟸ primarily because I think for folks who are new, it helps to indicate that this is a logical implication, and the direction it has.

Does this help?