#!/usr/bin/env ruby -s
#!/usr/local/bin/ruby -s

# First line of input must be a header.
# The "column headers" are separated the same way all rows are.
# Each column header is of the form "name: type" where ": type" is optional.
# "type" should be one of "string" (the default),
# "integer", "decimal", "date", or "/regular expression/".

# Need a header class of some sort. Parse the first line to create it.

# Cut just the columns specified.
# usage ruby -s rprojection.rb -columns=two,five [filenames]
# All lines before the header are ignored.
# Eric Blossom - September 2004

# BUG: duplicate rows are not removed.
# work around: ruby -s rprojection.rb -columns=b,c in.tsv >tmp; (head -1 tmp; sed 1d tmp | sort -u); rm tmp
# - elb 2007-05-15

columns = ""
columns = $columns if $columns != nil

columnTitle = columns.split( /[,;] */ )
$; = "\t"
while gets

  line = chomp.split()

  if 1 == $.
    iCols = columnTitle.map { |x| line.index( x ) }
    iCols.delete( nil )
  end

  out = iCols.map { |x| line[x] }
  puts out.join( $; ) if ! out.empty?

end