Task: Range expansion




Go: package main

import (
    "fmt"
    "strconv"
    "strings"
)

const input = "-6,-3--1,3-5,7-11,14,15,17-20"

func main() {
    fmt.Println("range:", input)
    var r []int
    var last int
    for _, part := range strings.Split(input, ",") {
        if i := strings.Index(part[1:], "-"); i == -1 {
            n, err := strconv.Atoi(part)
            if err != nil {
                fmt.Println(err)
                return
            }
            if len(r) > 0 {
                if last == n {
                    fmt.Println("duplicate value:", n)
                    return
                } else if last > n {
                    fmt.Println("values not ordered:", last, ">", n)
                    return
                }
            }
            r = append(r, n)
            last = n
        } else {
            n1, err := strconv.Atoi(part[:i+1])
            if err != nil {
                fmt.Println(err)
                return
            }
            n2, err := strconv.Atoi(part[i+2:])
            if err != nil {
                fmt.Println(err)
                return
            }
            if n2 < n1+2 {
                fmt.Println("invalid range:", part)
                return
            }
            if len(r) > 0 {
                if last == n1 {
                    fmt.Println("duplicate value:", n1)
                    return
                } else if last > n1 {
                    fmt.Println("values not ordered:", last, ">", n1)
                    return
                }
            }
            for i = n1; i <= n2; i++ {
                r = append(r, i)
            }
            last = n2
        }
    }
    fmt.Println("expanded:", r)
}








Ada: with Ada.Text_IO; use Ada.Text_IO;
procedure Test_Range_Expansion is
   type Sequence is array (Positive range <>) of Integer;
   function Expand (Text : String) return Sequence is
      To    : Integer := Text'First;
      Count : Natural := 0;
      Low   : Integer;
      function Get return Integer is
         From : Integer := To;
      begin
         if Text (To) = '-' then
            To := To + 1;
         end if;
         while To <= Text'Last loop
            case Text (To) is
               when ',' | '-' => exit;
               when others => To := To + 1;
            end case;
         end loop;
         return Integer'Value (Text (From..To - 1));
      end Get;
   begin
      while To <= Text'Last loop 
         Low := Get;
         if To > Text'Last or else Text (To) = ',' then
            Count := Count + 1;
         else
            To := To + 1;
            Count := Count + Get - Low + 1;
         end if;
         To := To + 1;
      end loop;
      return Result : Sequence (1..Count) do
         Count := 0;
         To := Text'First;
         while To <= Text'Last loop 
            Low := Get;
            if To > Text'Last or else Text (To) = ',' then
               Count := Count + 1;
               Result (Count) := Low;
            else
               To := To + 1;
               for Item in Low..Get loop
                  Count := Count + 1;
                  Result (Count) := Item;
               end loop;
            end if;
            To := To + 1;
         end loop;
      end return;
   end Expand;
   procedure Put (S : Sequence) is
      First : Boolean := True;
   begin
      for I in S'Range loop
         if First then
            First := False;
         else
            Put (',');
         end if;
         Put (Integer'Image (S (I)));
      end loop;
   end Put;
begin
   Put (Expand ("-6,-3
end Test_Range_Expansion;