Compile-time optimized membership checks for static byte sequences.

comtains expands fixed sets of byte strings into zero-allocation, branch-ordered decision trees. The resulting ByteSet can be embedded directly into hot parsers, opcode dispatchers, or protocol classifiers without any runtime preprocessing.

Example

use comtains::{byte_set, ByteSet};

const KEYWORDS: ByteSet = byte_set![
    b"GET",
    b"POST",
    b"PUT",
    b"PATCH",
];

assert!(KEYWORDS.contains(b"POST"));
assert!(!KEYWORDS.contains(b"DELETE"));

Design

1. The byte_set! macro parses string or byte-sequence literals at compile time and builds a trie that merges shared prefixes.
2. Each branch records how many sequences pass through it; siblings are sorted by descending weight so the hottest paths are checked first.
3. The macro emits a nested match ladder that compares each byte via candidate.get(depth), returning early on the first mismatch.
4. Optional debug metadata mirrors the trie structure so unit tests and benchmarks can assert branch ordering.

comtains

comtains expands static byte sequences into zero-allocation matchers at compile time. The byte_set! macro emits a branch-ordered decision tree, keeping membership checks to a handful of predictable instructions—ideal for tight opcode dispatchers or protocol parsers.

use comtains::{byte_set, ByteSet};

const HTTP_METHODS: ByteSet = byte_set![b"GET", b"POST", b"PUT", b"PATCH"];

assert!(HTTP_METHODS.contains(b"GET"));
assert!(!HTTP_METHODS.contains(b"DELETE"));

How it works

1. All inputs are parsed at macro expansion time into a trie that shares common prefixes.
2. Each edge records how many sequences traverse it; siblings are sorted by descending weight to probe common paths first.
3. The macro generates a nested match ladder that compares candidate[depth], short-circuiting on the first mismatch.
4. Debug metadata is emitted alongside the matcher so tests and benchmarks can assert branch ordering or inspect the trie layout.