Module:User:Cscott/Advent Of Code 2023/Day 1 Explained

return (functionlocal builders = local function register(name, f) builders[name] = fendregister('advent.compat', function return require end)

local compat = myrequire('advent.compat')

--Infrastructure--

function split(str) lines = for s in string.gmatch(str, "[^\r\n]+") do table.insert(lines, s) end return linesend

function part1(frame) local s = mw.title.new(frame.args[1]):getContent return day1a(split(s))end

function part2(frame) local s = mw.title.new(frame.args[1]):getContent return day1b(split(s))end

--Part 1--

function day1a(lines) local sum = 0 for _,line in pairs(lines) do -- ignore everything but numbers local nums = string.gsub(line, "[^0-9]", "") -- ignore everything but the first and the last nums = string.sub(nums, 1, 1) .. string.sub(nums, -1, -1) -- coerce to integer n = 0 + nums sum = sum + n -- io.write(n, "\n") end -- io.write("Sum: ", sum, "\n") return sumend

--Part 2!--

local digits =

function findDigit(str) for d = 1, #digits do local word = digits[d] -- io.write("checking ",word,"\n") if string.sub(str, 1, #word)

word then return d, #word end end -- is the first character a digit? if string.match(str, "^[0-9]") then return (0 + string.sub(str, 1, 1)), 1 else return 0, 0 endend

function day1b(lines) local sum = 0 for _,line in pairs(lines) do local first local last -- find first digit i = 1 while i <= #line do local piece = string.sub(line, i) d, len = findDigit(piece) if len > 0 then first = d break else -- ignore this character i = i + 1 end end -- find last digit i = #line while i >= 1 do local piece = string.sub(line, i) d, len = findDigit(piece) if len > 0 then last = d break else -- ignore this character i = i - 1 end end -- ignore everything but the first and the last digit local n = (10*first) + last -- io.write(line, " -> ", n, "\n") sum = sum + n end return sumend

--Testing--

-- io.write("Sum: ", day1a(io.lines(compat.unpack(arg))), "\n")-- io.write("Sum: ", day1a(split(io.input("day1.example"):read("a"))), "\n")

-- io.write("Sum: ", day1b(split(io.input("day1b.example"):read("a"))), "\n")

return

end)

local modules = modules['bit32'] = require('bit32')modules['string'] = require('string')modules['strict'] = modules['table'] = require('table')local function myrequire(name) if modules[name]