############################################################################
#
#	File:     countlst.icn
#
#	Subject:  Program to count items in a list
#
#	Author:   Ralph E. Griswold
#
#	Date:     December 30, 1991
#
############################################################################
#
#   This file is in the public domain.
#
############################################################################
#
#     This program counts the number times each line of input occurs and
#  writes a summary.
#
#     With no option, the output is sorted first by decreasing count and within
#  each count, alphabetically. With the option -a, the output is sorted
#  alphabetically.
#
#  The option -t prints a total at the end.
#
############################################################################
#
#  Links: adlutils, options
#
############################################################################

link adlutils, options

procedure main(args)
   local line_count, counter, lines, opts, sort_method, line, total, count

   line_count := table(0)		# counts for each line
   counter := table()			# lists of lines for each count
   total := 0				# total number of lines

   opts := options(args,"at")
   sort_method := opts["a"]

   while line_count[read()] +:= 1 do
      total +:= 1
       
   if \sort_method then {		# alphabetical sort
      line_count := sort(line_count,3)
      while write(get(line_count),"\t",get(line_count))
      }
   else { 				# numerical sort, then alpha
      line_count := sort(line_count,4)
   
      while count := pull(line_count) do {
         /counter[count] := []
         put(counter[count],pull(line_count))
         }
   
      counter := sort(counter,3)
   
      while lines := sort(pull(counter)) do {
         count := pull(counter)
         every write(!lines,"\t",count)
         }
     }

   if \opts["t"] then write("\ntotal\t",total)

end