Matteo Landi's .plan RSS

> During World War II, the Navy realized it was losing a lot of aircraft and could better armor its planes to increase their survival.

Am I the only one having a hard time understanding the implementation of Data-Directed Programming, presented in SICP?

Dynamic variables in Node.js For those of you unfamiliar with it, Common Lisp has this concept of "dynamic variables", which are nothing more than _global_ variables with _dynamic_ scope; but what does it mean for a variable to have dynamic scope?

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+ book: [Smalltalk Best Practice Patterns](https://www.amazon.it/Smalltalk-Best-Practice-Patterns-Kent-dp-013476904X/dp/013476904X) ?

* finished reading [The Common Lisp Condition System](https://www.apress.com/gp/book/9781484261330) --- The "earnmuff notation" (extracted from the Common Lisp Condition System) The "earnmuff notation" in CL is the conventional notation for dynamic var…

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> While this was happening, the big sharks sensed an opportunity; larger trading professionals joined the fight but only for their own profit.

I wanted to fix some of the compilation warnings in my AdventOfCode-solutions-in-Common-Lisp [project](https://iamFIREcracker.github.com/adventofcode), and this one in particular caught my attention.

> "Great flight up...

> any legit use case for PROG2 though?

Advent of Code: [2015/25](https://adventofcode.com/2015/day/25) The task for today, i.e.

Advent of Code: [2015/23](https://adventofcode.com/2015/day/23) > Little Jane Marie just got her very first computer for Christmas from some unknown benefactor.

Advent of Code: [2015/22](https://adventofcode.com/2015/day/22) Another day, another RPG to play (err, implement); this time however, the game logic is a bit more complicated than the one we implemented for [2015/21](https://matteolandi.net/plan.html#day…

Advent of Code: [2015/21](https://adventofcode.com/2015/day/21) Today, we treat ourselves with a simple RPG game to play with: - It's you versus the "boss" - The boss starts with 100 hit points and with some pre-defined attack power and armor (all this…

> it's quite windy here its side down well though I good it's it's this is oh actually wasn't expected to be this windy hopefully you can actually hear what I'm saying okay great great so this is this is I think the most inspiring thing that I have ever s…

Advent of Code: [2015/19](https://adventofcode.com/2015/day/19) Rudolph (the Red-Nosed reindeer) is sick, and Santa needs your help to cure him; what exactly are you supposed to do?

Advent of Code: [2015/16](https://adventofcode.com/2015/day/16) > Your Aunt Sue has given you a wonderful gift, and you'd like to send her a thank you card.

Advent of Code: [2015/15](https://adventofcode.com/2015/day/15) > Today, you set out on the task of perfecting your milk-dunking cookie recipe.

Advent of Code: [2015/13](https://adventofcode.com/2015/day/13) Today, we are challenged with finding the _optimal seating arrangement_ that minimizes those awkward conversations.

Advent of Code: [2015/10](https://adventofcode.com/2015/day/10) Today's task, is to implement the [Look-and-say sequence](https://en.wikipedia.org/wiki/Look-and-say_sequence); in particular, given an initial list of digits, we are asked to "play" this ga…

Advent of Code: [2015/09](https://adventofcode.com/2015/day/9) Given a list of locations and the distances between every pair (of locations), what's shortest distance you have to travel to visit them all?

* Changed [vim-lispindent](https://github.com/iamFIREcracker/vim-lispindent/commit/1d34ede0a1a1a66d55e08215e0c12cb0042b681b) to use a customized `indentexpr` function instead of the combination of 'lisp' mode and `&lispwords`.

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Advent of Code: [2015/04](https://adventofcode.com/2015/day/4) AdventCoins mining!

Advent of Code: [2015/02](https://adventofcode.com/2015/day/2) We are given a list presents/boxes dimensions (i.e. `12x34x45` with `12` being the length of the box, `34` being the width, and `45` the height), and we are asked to calculate how much paper…

Finally fixed some weird indentation problems with my Vim/CL setup Every time one of my files included a `#\(`, _bad_ things will happen: - matchit's `%` mappings would land me on the the closing parenthesis immediately _after_ the expected one - vim-se…

TIL: the first LOOP's `:thereis` non-NIL form is also going to be the return value of the LOOP form itself (loop for e in '(1 2 3 5 7) thereis (evenp e)) => T What if you wanted to return return the first _odd_ element, and not just

Is it possible pass to CHECK-TYPE a _parametric_ type?

Advent of Code: [2020/25](https://adventofcode.com/2020/day/25) Solution: - Bruteforce the "loop-size" param for one of the 2 inputs - _transform_ the other input with the found "loop-size" (defparameter *magic* 20201227) (defun transform (sub…

Advent of Code: [2020/24](https://adventofcode.com/2020/day/24) Solution: - [Pointy topped](https://www.redblobgames.com/grids/hexagons/) hex grids - Parse instructions into list of steps, i.e.

Advent of Code: [2020/23](https://adventofcode.com/2020/day/23) Solution: - Create a _circular_ list -- let's thank Quickutil's [NCYCLE](http://quickutil.org/list?

Advent of Code: [2020/22](https://adventofcode.com/2020/day/22) Solution: - Nothing crazy, just do as told -- I thought about using a deque to implement a deck, but as it turns out a LIST will do just fine - Part 1: pop, pop, compare, append, until one…

Advent of Code: [2020/21](https://adventofcode.com/2020/day/21) Solution: - Parse food into a list having the list of ingredients as first element, and the list of allergens as second -- i.e.

Advent of Code: [2020/20](https://adventofcode.com/2020/day/20) Solution: - Parse input tiles into LISTs having the id as first element, followed by the content of the tile (first row of data, second row of data...) -- `(list 1234 "...#....." ".#.#..#.."

Advent of Code: [2020/19](https://adventofcode.com/2020/day/19) Solution: - Use input rules to generate a _massive_ regexp -- it took me a couple of hours to realize I could indeed solve this using regexps!

Advent of Code: [2020/18](https://adventofcode.com/2020/day/18) Solution: - Parse each expression into an [S-expression](https://en.wikipedia.org/wiki/S-expression) - Feed each to EVAL - Sum the results I implemented the parsing logic by combining toge…

Advent of Code: [2020/17](https://adventofcode.com/2020/day/17) Solution: - Classic [Conway's Game of Life](https://en.wikipedia.org/wiki/Conway%27s_Game_of_Life) (even the rules were the same); the only difference is that the game evolves in 3 dimensio…

Advent of Code: [2020/16](https://adventofcode.com/2020/day/16) Solution: - Parse rules into LISTs having the name of the rule as first argument, and two _ranges_ as second and third element (a range is just an improper list containing two numbers: the…

Advent of Code: [2020/15](https://adventofcode.com/2020/day/15) Solution: - two HASH-TABLEs - one to keep track of the last time a given number was spoken - one to keep track of the second-to-last time a given number was spoken - for each spoken number:…

Advent of Code: [2020/14](https://adventofcode.com/2020/day/14) Solution: - Parse each "mask = ..." input line into a pair of bit-masks: one for all the "0"s, one for all the "1"s - "mem[...] = ..." lines instead are parsed into pairs containing the loc…

Advent of Code: [2020/13](https://adventofcode.com/2020/day/13) I knew the `x`s in the input were going to be used for part 2, so I decided to _manually_ parse the input and try to solve this directly from the REPL.

Advent of Code: [2020/12](https://adventofcode.com/2020/day/12) Solution: - Use complex numbers to represent the position and the bearing of the ship - Turning left by 90 degrees means multiplying your bearing by _i_ (i.e.

Advent of Code: [2020/11](https://adventofcode.com/2020/day/11) Solution: - Parse the seating layout into a HASH-TABLE (I thought about using a 1D or 2D ARRAY, but figured the HASH-TABLE would make things a bit easier as I would not have to worry about…

Advent of Code: [2020/10](https://adventofcode.com/2020/day/10) Solution: - Part 1 - Sort connectors - Calculate deltas between adjacents connectors - Part 2 - Top-down dynamic programming (i.e. recursion + memoization) - Start from joltage of 0, and ca…

Advent of Code: [2020/09](https://adventofcode.com/2020/day/09) Solution: - Part 1 - Implement a sliding-window HASH-SET of 25 elements - For each number after the 25th, check if it's valid, and if not, remove the oldest element from the set, and add the

Advent of Code: [2020/08](https://adventofcode.com/2020/day/08) Solution: - Instructions are parsed into a plist, e.g.

Advent of Code: [2020/07](https://adventofcode.com/2020/day/07) Solution: - Parse the input into a list of _rules_, where each rule looks like: `(:muted-white ((:posh-chartreuse . 1) (:dim-silver . 1) (:posh-bronze . 4) (:striped-black . 1)))` - Part 1:…

Advent of Code: [2020/06](https://adventofcode.com/2020/day/06) Solution: - Parse groups of answers using similar logic used for 2020/04 -- a group of answers is a list of list of characters - Part 1: reduce the answers of each group using UNION to get…

Advent of Code: [2020/05](https://adventofcode.com/2020/day/05) Solution: - Intuition 1: boarding passes are just binary numbers (e.g.