Placeholder Highlighter for Neovim

A simple but powerful Neovim plugin that highlights C-style format specifiers (like %d, %f, %s) inside strings.

This is especially useful for languages like C, C++, Go, Python, Lua, etc., where the built-in syntax highlighting might not distinguish these placeholders from the rest of the string. This plugin makes them stand out, improving code readability.

Features

• Accurate Highlighting: Uses a precise regex to correctly identify complex format specifiers, including flags, width, precision, and length modifiers (e.g., %-10.2f, %lld).
• Optimized: Highlighting updates are debounced to ensure smooth performance even in large files.
• Configurable: Easily customize the highlight color, supported filetypes, and performance settings.

Installation & Configuration

This plugin is designed to be configured using the standard setup(opts) pattern.

Here is an example for the lazy.nvim plugin manager.

return {
  "Joreh-T/placeholder_highlighter.nvim",

  -- Load the plugin
  event = "VeryLazy",

  opts = {
    -- Example: Link the highlight to your theme's 'SpecialChar' group
    highlight = { link = "SpecialChar" },

    -- Example: Add 'rust' and 'typescript' to the list of supported filetypes
    filetypes = {
      "c",
      "cpp",
      "python",
      "lua",
      "go",
      "rust",
      "typescript",
    },

    -- Example: Change the debounce delay to 200ms
    debounce = 200,
  },
}

Configuration Options

You can pass any of the following options to the setup function.

Option	Description	Default Value
highlight	A highlight table to customize the placeholder color. You can link to an existing group or define a new one.	{ fg = "#e06c75", bold = true } (Red, Bold)
filetypes	A list of filetypes where the plugin should be active.	{ "c", "cpp", "python", "lua", "go" }
debounce	The delay in milliseconds for debouncing the highlight update on text change.	100