#!/usr/bin/env ruby
# stem [-0] PAT SUBST... -- ... - substitute make(1)-style percent patterns
#
# Pattern groups are split by --.  For the first pattern group where
# PAT matches, substitute the first % in all SUBST and print them.
# Patterns without / match the basename.

if ARGV[0] == "-0"
  ARGV.shift
  $\ = $/ = "\0"
else
  $\ = $/ = "\n"
end

stems = ARGV.inject([[]]) { |a, e|
  if e == "--"
    a << []
  else
    a.last << e
  end
  a
}

while line = STDIN.gets
  line.chomp!

  stems.each { |base, *gens|

    if base.index("/")
      dir = ""
    else
      dir, line = File.split(line)
      if dir == "."
        dir = ""
      else
        dir << "/"
      end
    end

    if i = base.index("%")
      if line.size >= base.size &&
         line.start_with?(base[0...i]) &&
         line.end_with?(base[i+1..-1])
        gens.each { |gen|
          if j = gen.index("%")
            print "#{gen[0...j]}#{dir}#{line[i..-base.size+i]}#{gen[j+1..-1]}"
          else
            print "#{dir}#{gen}"
          end
        }
        break
      end
    else
      if line == base
        gens.each { |gen|
          print "#{dir}#{gen.sub('%', line)}"
        }
      end
    end

  }
end