> For the complete documentation index, see [llms.txt](https://docs.internetobject.org/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.internetobject.org/structure-and-syntax/structural-elements/whitespaces.md). # Whitespace & Indentation In the Internet Object format, whitespace is any character with a Unicode code point less than or equal to `U+0020` (the range `U+0000` to `U+0020`). This range covers both non-printable control characters and common whitespace such as the horizontal tab (`U+0009`), newline (`U+000A`), vertical tab (`U+000B`), form feed (`U+000C`), carriage return (`U+000D`), and space (`U+0020`). Because the format is not whitespace-sensitive, indentation carries no meaning: it is ordinary whitespace between tokens. You may indent objects, arrays, and definitions freely for readability without changing how a document parses. ## EBNF definition ```ebnf whitespace = ascii_whitespace | unicode_whitespace ; ascii_whitespace = ? any character with Unicode code point U+0000 to U+0020 ? ; unicode_whitespace = U+1680 | U+2000 | U+2001 | U+2002 | U+2003 | U+2004 | U+2005 | U+2006 | U+2007 | U+2008 | U+2009 | U+200A | U+2028 | U+2029 | U+202F | U+205F | U+3000 | U+FEFF ; ``` Beyond the `U+0000`–`U+0020` range, the format also treats characters in the Unicode whitespace category as whitespace, such as the non-breaking space (`U+00A0`), em space (`U+2003`), and en space (`U+2002`). Recognizing these makes the format easier to work with in languages that use non-Latin scripts, such as Arabic, Chinese, or Japanese. The format also recognizes the zero-width non-breaking space (`U+FEFF`) as whitespace. This character is often used as a byte order mark (BOM) in Unicode-encoded documents. ## Whitespace characters The following table lists the valid whitespace characters: | Code points | Description | Notes | | -------------------- | -------------------------------------------- | ----------------------------------------------------------------------------------------- | | `U+0000` to `U+0020` | Space, line feed, carriage return, tab, etc. | Any character with code point `<= 0x20`. Includes the ASCII space and control characters. | | `U+1680` | Ogham space mark | Space used in Ogham script. | | `U+2000` | En quad | Space equal to the width of the lowercase letter "n". | | `U+2001` | Em quad | Space equal to the width of the uppercase letter "M". | | `U+2002` | En space | Space equal to half the width of the em space. | | `U+2003` | Em space | Space equal to the width of the em space. | | `U+2004` | Three-per-em space | Space equal to one-third of an em space. | | `U+2005` | Four-per-em space | Space equal to one-quarter of an em space. | | `U+2006` | Six-per-em space | Space equal to one-sixth of an em space. | | `U+2007` | Figure space | Space equal to the width of a numeral. | | `U+2008` | Punctuation space | Space used for punctuation. | | `U+2009` | Thin space | Space narrower than the regular space. | | `U+200A` | Hair space | Very narrow space used for special purposes. | | `U+2028` | Line separator | Separates lines of text. | | `U+2029` | Paragraph separator | Separates paragraphs of text. | | `U+202F` | Narrow no-break space | Non-breaking space narrower than the regular space. | | `U+205F` | Medium mathematical space | Space used in mathematical notation. | | `U+3000` | Ideographic space | Space used in East Asian scripts. | | `U+FEFF` | Byte order mark (BOM) | Zero-width non-breaking space, often used as a BOM. | ## Rules * **Whitespace insensitive** — the parser ignores whitespace surrounding values and structural elements. * **Preserved inside strings** — whitespace within a value or string is kept exactly as written. * **Recognized by code point** — whitespace is identified by Unicode code point, per the table above. * **Reserved** — these whitespace characters must not appear within identifiers or keys. ## Best practices * **Aid readability** — use spaces and tabs to format a document so it is easy to read. * **Avoid clutter** — excessive whitespace adds no meaning and reduces readability. * **Stay consistent** — apply whitespace uniformly across a document for easier maintenance. * **Watch for invisible characters** — zero-width and other invisible spaces can slip into keys or values unnoticed; avoid pasting them in. ## See Also * [Encoding](/structure-and-syntax/encoding.md) — Unicode handling and document encoding * [Strings](/structure-and-syntax/values/string.md) — whitespace handling inside strings --- # Agent Instructions This documentation is published with GitBook. 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