hikari (光)

The pluggable syntax-highlighting spine for pleme-io editors and tools.

hikari-core is a small, zero-dependency library that owns the narrow interface every language backend lowers to:

• ByteSpan + HlClass — a palette-independent, byte-offset highlight model produced only through a forward-cursor SpanSink that makes gapped / overlapping / reversed partitions unrepresentable: every byte is classified exactly once, by construction.
• LanguageLexer — the authored backend trait. Its associated LineState: Copy + Eq makes incremental line-restart re-lex a type property, not a hand-coded optimization.
• Highlighter — an object-safe render-facing trait, bridged from any LanguageLexer by the blanket LineDriven adapter (no backend hand-writes it).
• Ecosystem — a registry with total, panic-free resolution: an unknown extension resolves to PLAIN_TEXT, never a panic, never "everything is one language".
• Theme — HlClass → Rgb (Nord by default).

Batteries included: a table-driven backend covering Rust, Python, Lisp, JSON, TOML, Markdown ships in the box.

use hikari_core::{Ecosystem, NordTheme, Theme};

let eco = Ecosystem::with_builtins();
let hl = eco.highlighter_for_path("src/main.rs");   // -> a Rust highlighter
for span in hl.highlight("fn main() {}") {
    let rgb = NordTheme.color(span.class);
    // paint &text[span.span.range()] in `rgb`
}

Why zero dependencies

The spine must vendor with no transitive weight into any consumer — an egui/GPU editor, a TUI, a CLI. Heavier backends (tree-sitter grammars, the tatara-lisp macro-generated (deflexer …) output) ship as separate hikari-* crates in this workspace and satisfy the same traits, so adding a language is additive and never forces a dependency on consumers that don't use it.

Published

hikari-core is published to crates.io on every merge to main via pleme-io AUTO-RELEASE.

License

MIT.