sigil

Prettify symbols for Neovim. Visually replaces text patterns with Unicode symbols while you edit. The file on disk is never modified.

\alpha displays as α, \to as →, -> as →, and so on.

Based on the idea of Emacs prettify-symbols-mode, extended with context awareness, word boundary analysis, atomic motions, and math region support.

Demo

Atomic motions (default, no unprettify)

Symbols stay prettified at all times. Navigation and editing work as if each symbol were a single character.

Unprettify at point (unprettify_at_point = true)

The symbol under the cursor reverts to original text. Other symbols on the line remain prettified.

Unprettify line (unprettify_at_point = "line")

All symbols on the cursor line revert to original text. When the cursor moves to another line, the previous line is re-prettified.

Features

• Pattern → symbol replacement using extmarks (no file modification)
• Context awareness -- skip strings and comments via Tree-sitter (with syntax fallback)
• Math context -- restrict symbols to math regions in LaTeX/Typst ($...$, \[...\], etc.)
• Atomic motions -- h, l, w, b, e, x, s, c treat symbols as single characters
• Unprettify at point -- reveal original text under cursor or on cursor line
• Per-symbol highlight groups -- color symbols by category
• Lazy prettification -- large files are prettified on demand (visible area only)
• Word boundaries -- automatic boundary checks prevent partial matches (in won't match inside integral)

Requirements

• Neovim >= 0.9.0
• A font with Unicode symbol support
• Tree-sitter parsers (optional, for context-aware filtering)

Installation

With lazy.nvim:

{
  "Prgebish/sigil.nvim",
  config = function()
    require("sigil").setup({
      filetypes = { "tex", "plaintex", "latex", "typst" },
      filetype_symbols = {
        tex = {
          { pattern = "\\alpha", replacement = "α", boundary = "left" },
          { pattern = "\\beta",  replacement = "β", boundary = "left" },
          { pattern = "\\to",    replacement = "→" },
          { pattern = "\\leq",   replacement = "≤" },
        },
      },
    })
  end,
}

Quick start

Minimal LaTeX setup:

require("sigil").setup({
  filetypes = { "tex", "plaintex", "latex" },
  filetype_symbols = {
    tex = {
      { pattern = "\\alpha", replacement = "α", boundary = "left" },
      { pattern = "\\to",    replacement = "→" },
      { pattern = "\\infty", replacement = "∞" },
    },
  },
})

Open a .tex file -- every \alpha displays as α, \to as →, \infty as ∞.

Symbol formats

Map format -- simple pattern → replacement:

symbols = {
  ["\\to"]  = "→",
  ["\\leq"] = "≤",
}

List format -- allows boundary and hl_group per symbol:

symbols = {
  { pattern = "\\alpha", replacement = "α", boundary = "left" },
  { pattern = "\\sum",   replacement = "∑", boundary = "left", hl_group = "Special" },
}

Structured format -- organize symbols by math context:

filetype_symbols = {
  typst = {
    math = {
      -- Only prettified inside $...$
      { pattern = "alpha", replacement = "α", boundary = "left" },
      { pattern = "sum",   replacement = "∑", boundary = "left" },
    },
    text = {
      -- Only prettified outside math
    },
    any = {
      -- Prettified everywhere
      { pattern = "->", replacement = "→" },
    },
  },
}

Boundary modes

The boundary field controls word boundary checks:

Value	Description
"both" (default)	Check left and right boundaries
"left"	Check only left boundary. Allows subscripts on the right: \sum_{i=0}, alpha_1
"right"	Check only right boundary
"none"	No boundary checks

Commands

Command	Description
:Sigil	Toggle sigil on/off for current buffer
:SigilEnable	Enable for current buffer
:SigilDisable	Disable for current buffer
:SigilBenchmark	Run performance benchmark

Configuration

require("sigil").setup({
  enabled = true,
  symbols = {},                  -- global symbols (all filetypes)
  filetype_symbols = {},         -- per-filetype symbols
  filetypes = {},                -- filetypes to enable (or "*" for all)
  excluded_filetypes = {},       -- filetypes to exclude
  conceal_cursor = "nvic",       -- modes where cursor line stays concealed
  update_debounce_ms = 30,       -- debounce for incremental updates
  skip_strings = true,           -- skip inside string literals
  skip_comments = true,          -- skip inside comments
  atomic_motions = true,         -- symbols behave as single chars for motions
  unprettify_at_point = nil,     -- nil | true | "line"
  hl_group = nil,                -- default highlight group for symbols
  -- Performance (large files)
  lazy_prettify_threshold = 500, -- lazy mode for files > N lines
  lazy_prettify_buffer = 50,     -- extra lines around visible area
  lazy_prettify_debounce_ms = 50,
})

See :help sigil for full documentation.

Like it?

If you find sigil useful, please star the repository -- it helps others discover the plugin.

License

MIT