space-bender

Codewars katas + verified solutions — the space bender.

A curated collection of solved katas, each with its solution, a README.md explaining the approach, and tests that verify the solution exhaustively (Python suites for the Python katas, a Node harness against the real @codewars/lambda-calculus compiler for the λ Calculus ones). Solutions are written from first principles and verified locally before being recorded here.

Katas

2 kyu

Kata	Solution	Approach
Evaluate mathematical expression	calc.py	Recursive descent parser, no eval
Simpler Interactive Interpreter	interpreter.py	Recursive descent REPL with variable state
Regular Expression parser	regexp.py	Recursive descent AST builder
Prime Streaming (NC-17)	primes.py	Segmented sieve, C-level bytearray + regex
Divisible by 0b111 (7)	solution.py	7-state DFA → state elimination → regex

3 kyu

Kata	Solution	Approach
Loopover	solution.py	Local 3-cycles (swap_adj, three_slip) + parity

6 kyu

Kata	Solution	Approach
Basics 08: next higher with same bits (λ Calculus)	solution.lc	BinaryScott Gosper walk — Even/Odd wrap accumulators

7 kyu

Kata	Solution	Approach
Number Pairs (λ Calculus)	solution.lc	Church lists + pred-trick tail + monus max
Fibonacci (λ Calculus)	solution.lc	Scott pair-iteration + lazy Scott add via Z
Spinning Rings (λ Calculus)	solution.lc	Scott ring-state walk (decw/incw) + Z structural eq

Kumite

Kata	Solution	Approach
Finding the duplicate number (Haxe)	solution.hx	Single O(n) seen-map pass vs length-branched baseline

Running tests

python3 katas/2kyu/divisible-by-7/test_solution.py
python3 katas/3kyu/loopover/test_solution.py
npm install --prefix katas/7kyu/number-pairs && node katas/7kyu/number-pairs/test.mjs
npm install --prefix katas/6kyu/basics-08-next-higher && node katas/6kyu/basics-08-next-higher/test.mjs
npm install --prefix katas/7kyu/fibonacci && node katas/7kyu/fibonacci/test.mjs
npm install --prefix katas/7kyu/spinning-rings && node katas/7kyu/spinning-rings/test.mjs

the constellation · 0 + 1 · fine touch from within · vaked.dev