bijecta

#!/usr/bin/env bash
# vim: set ft=ruby:

# This file executes as a bash script, which turns around and executes Ruby via
# the line below. The -x argument to Ruby makes it discard everything before
# the second "!ruby" shebang. This allows us to work on Linux, where the
# shebang can only have one argument so we can't directly say
# "#!/usr/bin/env ruby --disable-gems". Thanks for that, Linux.
#
# If this seems confusing, don't worry. You can treat it as a normal Ruby file
# starting with the "!ruby" shebang below.

exec /usr/bin/env ruby --disable-gems -x "$0" $*
#!ruby

if ARGV.to_a == ["help"]
  puts "USAGE: bijecta <regexp> <subcommand>"
  puts 
  puts "Runs each line of stdin through `regexp`, into `command`, then "
  puts "prints out the original lines."
  puts 
  puts "  regexp - A ruby regular expression with a single group."
  puts "           The matched group will get passed to the subcommand."
  puts "  command - Command to filter the matched groups. The output is then"
  puts "            matched with the initial input to bijecta"
  puts
  puts "Example:"
  puts " # Identity"
  puts " echo 1,foo | bijecta \"\d,(.*)\" \"xargs -I {} echo {}\""
  puts " # Selecta - select presents stdin as a list to be chosen from, and echos the chosen line to stdout"
  puts " echo 1,foo | bijecta \"\d,(.*)\" selecta"
  exit 0
end
regex = Regexp.new ARGV[0]


command = ARGV[1]

keyed = {}
lines = []
$stdin.each_line do |line|
  key = line[regex, 1]
  keyed[key] = line
  lines << key
end

chosen = IO.popen(command, "r+") do |child|
  lines.each do |line| child.puts line end
  child.close_write
  child.read
end

puts keyed[chosen.chomp]