[
    {
        "role": "user",
        "content": "emacs%20allows%20%3B%20and%20multiple%20%3B%20for%20comments.%20is%20there%20some%20hierarchy%3F%20like%20comment%20headling%20level%201%202%20or%203.%20or%20top%20level%20comment%20vs%20function%20comment.%20how%20many%20%3B%20to%20use%3F"
    },
    {
        "role": "assistant",
        "content": "Emacs Lisp has a well-established convention for using semicolons (`;`) in comments. The number of semicolons \u2014 one, two, three, or more \u2014 signals different roles or \"levels\" of comments. These conventions aren't enforced by syntax, but Emacs modes (especially Lisp mode) understand them and indent accordingly, and tools like outline-minor-mode use them to detect headings. ([gnu.org](https://www.gnu.org/software/emacs/manual/html_node/elisp/Comment-Tips.html?utm_source=openai))\n\n---\n\n## What each number of semicolons means\n\nHere are the typical meanings, from most specific/thin (inline comments) to most global (file- or section-level headings):\n\n| # of semicolons | Position & indentation | Usage / Semantics |\n|------------------|--------------------------|---------------------|\n| `;` (one semicolon) | Inline, after code on the same line | Explains \u201cwhat this code does,\u201d commentary specific to that expression. The comment starts at same line as code, aligned to comment-column (configurable). ([gnu.org](https://www.gnu.org/software/emacs/manual/html_node/elisp/Comment-Tips.html?utm_source=openai)) |\n| `;;` (two semicolons) | Starting a line of its own, indented to the level of the code it's commenting on | Describes following code blocks, or gives context for layout; also used just before function definitions if there's no docstring. Usually aligned with the code. ([ftp.gnu.org](https://ftp.gnu.org/old-gnu/Manuals/elisp-manual-20-2.5/html_chapter/elisp_41.html?utm_source=openai)) |\n| `;;;` (three semicolons) | At the left margin (i.e. column zero), used for headings in Outline minor mode | Marks \u201csection\u201d headings; also used when referring to large blocks or entire file parts. Anything with \u22653 semicolons (then a space, then non-whitespace) is treated as a section heading by many tooling. ([gnu.org](https://www.gnu.org/software/emacs/manual/html_node/elisp/Comment-Tips.html?utm_source=openai)) |\n| `;;;;` (four semicolons) or more | Also left margin; visually nested under 3-semicolon headings | Used for high-level sections or subheadings: deeper levels use more semicolons. Helps in structuring the file. ([ftp.gnu.org](https://ftp.gnu.org/old-gnu/Manuals/elisp-manual-20-2.5/html_chapter/elisp_41.html?utm_source=openai)) |\n\n---\n\n## Hierarchy / Structure\n\nThere's a loose hierarchy:\n\n- **\u2039 `;` ** is for tiny, inline comments.\n- **`;;`** for local commentary in code: before expressions, code blocks, function definitions (if there's no docstring), or just general comments matched to code indentation.\n- **`;;;`** marks file-sections, big chunks, or headings. Tools like outline-minor-mode identify these as section boundaries. ([gnu.org](https://www.gnu.org/software/emacs/manual/html_node/elisp/Comment-Tips.html?utm_source=openai))\n- **`;;;;`** (or more) are subheadings below `;;;` headings: to allow nesting of sections within sections. ([ftp.gnu.org](https://ftp.gnu.org/old-gnu/Manuals/elisp-manual-20-2.5/html_chapter/elisp_41.html?utm_source=openai))\n\nSo yes, there *is* a kind of hierarchy: more semicolons = higher (or broader) level in the outline.\n\n---\n\n## How many semicolons *should* you use?\n\nHere are practical guidelines:\n\n- Use `;` only for inline, in-line commentary: code on that line, comment afterward. Example:\n  \n  ```elisp\n  (setq x y) ; compute x from y\n  ```\n\n- Use `;;` for commentary when the comment is on its own line, or just before a function definition (if docstring isn't available), or to explain code blocks. Keep it indented like the code around it.\n\n- Use `;;;` for high-level sections of code. If writing a library/package, you\u2019ll often see at the top:\n\n  ```elisp\n  ;;; mylib.el --- what this library does\n  ;;; Commentary:\n  ;;; Code:\n  ```\n\n  And within the file, `;;;` headings for subsections. `;;;;` (or more) can be used for finer subdivision.\n\n- Don\u2019t overdo semicolons: you probably don\u2019t need beyond `;;;;` unless your file is very big or deeply subdivided. Consistency within a project matters more than perfect nesting levels.\n\n---\n\n## What Emacs/Lisp mode does with these\n\n- The `TAB` or `lisp-indent-line` commands indent `;;`-comments based on where code is; `;;;`-comments at column zero are usually left alone. ([flylib.com](https://flylib.com/books/en/2.27.1.87/1/?utm_source=openai))\n\n- The command `M-;` (aka `comment-dwim`) often picks the appropriate number of semicolons and places/indents the comment in the convention in use. ([gnu.org](https://www.gnu.org/software/emacs/manual/html_node/elisp/Comment-Tips.html?utm_source=openai))\n\n- Outline-minor-mode treats lines starting with `;;;` (three semicolons + space + non-whitespace) as headings. More semicolons = deeper nesting. ([gnu.org](https://www.gnu.org/software/emacs/manual/html_node/elisp/Comment-Tips.html?utm_source=openai))\n\n---\n\nIf you like, I can show you a few concrete examples from popular Emacs Lisp packages so you can see how people use them in practice."
    }
]