challenge-091/paulo-custodio/lua/ch-1.lua


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#!/usr/bin/env lua

--[[
Challenge 091

TASK #1: Count Number

You are given a positive number $N. Write a script to count number and
display as you read it.

Solution with regular expressions:
Just match the first digit and a sequence of equal matches, capture the
results and show them.
--]]

function count_number(n)
    local inp, out = tostring(n), ''
    while (inp ~= '') do
        local digit = string.match(inp, "^%d")
        local digits = string.match(inp, "^"..digit.."+")
        out = out..tostring(#digits)..digit
        inp = string.sub(inp, #digits+1)
    end
    return out
end

print(count_number(tonumber(arg[1])))