PostgreSQL string character replacement

Question

I\'m trying to write a lexical database for storing words comprised of roots and patterns, and I was wondering how I could create a column that will combine the root and pattern

Answer 1

I must admit to not liking to do much string manipulation in sql/plpgsql functions. Perl has an operator for replacing regexp matches with generated replacements, which works fairly nicely:

create or replace function splice_to_word(root text, root_i text)
  returns text strict immutable language plperl as $$
  my $roots = shift;
  my $template = shift;
  $template =~ s{(\d+)}{substr($roots,$1-1,1)}ge;
  return $template;
$$;

There is some nastiness in that postgresql arrays don't seem to be translated into Perl lists, so I've assumed the roots are passed in as a string, e.g.:

select root, root_i, splice_to_word(array_to_string(root, ''), root_i) from data