smalto

A general-purpose syntax highlighting library for Gleam.

Smalto uses regex-based grammars inspired by Prism.js to tokenize source code for 30 programming languages, with output to structured tokens, ANSI terminal colors, or HTML.

Usage

import smalto
import smalto/languages/python

let html = smalto.to_html("print('hello')", python.grammar())
let ansi = smalto.to_ansi("print('hello')", python.grammar())
let tokens = smalto.to_tokens("print('hello')", python.grammar())

Each language module exports a single grammar() function that returns the language’s Grammar definition. Pass it directly to to_tokens, to_html, or to_ansi along with the source code to highlight.

Values

to_ansi

</>

pub fn to_ansi(code: String, grammar: grammar.Grammar) -> String

Render syntax-highlighted text with ANSI terminal color codes using the default color theme.

Each token type is mapped to a specific terminal color.

to_ansi_with

</>

pub fn to_ansi_with(
  code: String,
  grammar: grammar.Grammar,
  theme: ansi_theme.AnsiTheme,
) -> String

Render syntax-highlighted text with ANSI terminal color codes using a custom color theme.

to_html

</>

pub fn to_html(code: String, grammar: grammar.Grammar) -> String

Render syntax-highlighted HTML from source code.

Tokens are wrapped in <span class="smalto-{name}"> elements with HTML-escaped content. Whitespace and unmatched text are output as-is.

to_tokens

</>

pub fn to_tokens(
  code: String,
  grammar: grammar.Grammar,
) -> List(token.Token)

Tokenize source code into a list of tokens using the given grammar.

Cross-language LanguageRef references in grammar rules are resolved automatically using the built-in language registry.