Module syntax_highlight 

Syntax Highlighting Engine

Global syntax highlighting using syntect with TextMate themes. Follows the architecture from OpenAI Codex PRs #11447 and #12581.

Architecture

• SyntaxSet: Process-global singleton (~250 grammars, loaded once)
• ThemeSet: Process-global singleton loaded once
• Highlighting: Guardrails skip large inputs (>512KB or >10K lines)

Usage

use crate::ui::syntax_highlight::{
    highlight_code_to_segments, get_active_syntax_theme
};
use crate::ui::theme::active_theme_id;

// Auto-resolve syntax theme from current UI theme
let syntax_theme = get_active_syntax_theme();

// Highlight code with proper theme
let segments = highlight_code_to_segments(code, Some("rust"), syntax_theme);

Performance

• Single SyntaxSet load (~1MB, ~50ms)
• Single ThemeSet load shared by all highlighters
• Input guardrails prevent highlighting huge files
• Parser state preserved across multiline constructs

Structs

DiffScopeBackgroundRgbs

Raw RGB diff backgrounds extracted from syntax theme scopes.

Functions

available_themes

Get all available theme names

default_theme_name

Get the default syntax theme name

diff_scope_background_rgbs

Resolve diff-scope background colors from the currently active syntax theme.

find_syntax_by_extension

Find syntax by file extension

find_syntax_by_name

Find syntax by exact name

find_syntax_by_token

Find syntax by language token (e.g., “rust”, “python”)

find_syntax_plain_text

Get plain text syntax fallback

get_active_syntax_theme

Get the recommended syntax theme for the current UI theme

get_syntax_theme

Get the recommended syntax theme for a specific UI theme

highlight_code_to_ansi

Convert code to ANSI escape sequences

highlight_code_to_anstyle_line_segments

Highlight code and convert to anstyle segments with optional bg stripping.

highlight_code_to_line_segments

Highlight code and return styled segments per line.

highlight_code_to_segments

Highlight code and return styled segments

highlight_line_for_diff

Highlight a single line (for diff rendering)

highlight_line_to_anstyle_segments

Highlight one line and convert to anstyle segments with optional bg stripping.

load_theme

Load a theme from the process-global theme set.

should_highlight

Check if input should be highlighted (guardrails)

syntax_set

Get the global SyntaxSet reference