TOML: English v1.0.0-rc.2

<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8" /> <meta name="viewport" content="width=device-width, initial-scale=1.0" /> <meta http-equiv="X-UA-Compatible" content="ie=edge" /> <title>TOML: English v1.0.0-rc.2</title> <link rel="icon" type="image/png" href="/favicon.png" /> <link rel="stylesheet" href="/stylesheets/application.css" /> <script type="text/javascript" src="/javascripts/application.js"></script> </head> <body class="bg-white text-gray-900 font-sans antialiased" data-controller="application"> <header class="items-center bg-white shadow fixed left-0 right-0 z-30 border-t-4 border-orange-800"> <div class="flex flex-1 items-center p-3"> <a class="flex items-center font-mono tracking-tighter" href="index"> <svg class="w-10 mr-2" viewBox="0 0 128 128" xmlns="http://www.w3.org/2000/svg"> <g> <polygon class="fill-current text-orange-800" points="99.2359551 -7.08546829e-15 99.2359551 14.3820225 112.179775 14.3820225 112.179775 113.617978 99.2359551 113.617978 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md:text-right mt-16 md:mt-0"> Published on 8/9/2020 – <a href="https://raw.githubusercontent.com/toml-lang/toml.io/main/specs/en/v1.0.0-rc.2.md">Text version</a> </span> <h1 id="toml-v100-rc2">TOML v1.0.0-rc.2</h1> <p>Tom's Obvious, Minimal Language.</p> <p>By Tom Preston-Werner, Pradyun Gedam, et al.</p> <h2 id="objectives" data-target="nav.header"> <a href="#objectives">Objectives</a> </h2> <p>TOML aims to be a minimal configuration file format that's easy to read due to obvious semantics. TOML is designed to map unambiguously to a hash table. TOML should be easy to parse into data structures in a wide variety of languages.</p> <h2 id="spec" data-target="nav.header"> <a href="#spec">Spec</a> </h2> <ul> <li>TOML is case-sensitive.</li> <li>A TOML file must be a valid UTF-8 encoded Unicode document.</li> <li>Whitespace means tab (0x09) or space (0x20).</li> <li>Newline means LF (0x0A) or CRLF (0x0D 0x0A).</li> </ul> <h2 id="comment" data-target="nav.header"> <a href="#comment">Comment</a> </h2> <p>A hash symbol marks the rest of the line as a comment, except when inside a string.</p> <pre><code data-controller="snippet" class="language-toml"># This is a full-line comment key = "value" # This is a comment at the end of a line another = "# This is not a comment"</code></pre> <p>Control characters other than tab (U+0000 to U+0008, U+000A to U+001F, U+007F) are not permitted in comments.</p> <h2 id="keyvalue-pair" data-target="nav.header"> <a href="#keyvalue-pair">Key/Value Pair</a> </h2> <p>The primary building block of a TOML document is the key/value pair.</p> <p>Keys are on the left of the equals sign and values are on the right. Whitespace is ignored around key names and values. The key, equals sign, and value must be on the same line (though some values can be broken over multiple lines).</p> <pre><code data-controller="snippet" class="language-toml">key = "value"</code></pre> <p>Values must have one of the following types.</p> <ul> <li><a href="#string">String</a></li> <li><a href="#integer">Integer</a></li> <li><a href="#float">Float</a></li> <li><a href="#boolean">Boolean</a></li> <li><a href="#offset-date-time">Offset Date-Time</a></li> <li><a href="#local-date-time">Local Date-Time</a></li> <li><a href="#local-date">Local Date</a></li> <li><a href="#local-time">Local Time</a></li> <li><a href="#array">Array</a></li> <li><a href="#inline-table">Inline Table</a></li> </ul> <p>Unspecified values are invalid.</p> <pre><code data-controller="snippet" class="language-toml">key = # INVALID</code></pre> <p>There must be a newline (or EOF) after a key/value pair. (See <a href="#inline-table">Inline Table</a> for exceptions.)</p> <pre><code data-controller="snippet" class="language-toml">first = "Tom" last = "Preston-Werner" # INVALID</code></pre> <h2 id="keys" data-target="nav.header"> <a href="#keys">Keys</a> </h2> <p>A key may be either bare, quoted, or dotted.</p> <p><strong>Bare keys</strong> may only contain ASCII letters, ASCII digits, underscores, and dashes (<code>A-Za-z0-9_-</code>). Note that bare keys are allowed to be composed of only ASCII digits, e.g. <code>1234</code>, but are always interpreted as strings.</p> <pre><code data-controller="snippet" class="language-toml">key = "value" bare_key = "value" bare-key = "value" 1234 = "value"</code></pre> <p><strong>Quoted keys</strong> follow the exact same rules as either basic strings or literal strings and allow you to use a much broader set of key names. Best practice is to use bare keys except when absolutely necessary.</p> <pre><code data-controller="snippet" class="language-toml">"127.0.0.1" = "value" "character encoding" = "value" "ʎǝʞ" = "value" 'key2' = "value" 'quoted "value"' = "value"</code></pre> <p>A bare key must be non-empty, but an empty quoted key is allowed (though discouraged).</p> <pre><code data-controller="snippet" class="language-toml">= "no key name" # INVALID "" = "blank" # VALID but discouraged '' = 'blank' # VALID but discouraged</code></pre> <p><strong>Dotted keys</strong> are a sequence of bare or quoted keys joined with a dot. This allows for grouping similar properties together:</p> <pre><code data-controller="snippet" class="language-toml">name = "Orange" physical.color = "orange" physical.shape = "round" site."google.com" = true</code></pre> <p>In JSON land, that would give you the following structure:</p> <pre><code data-controller="snippet" class="language-json">{ "name": "Orange", "physical": { "color": "orange", "shape": "round" }, "site": { "google.com": true } }</code></pre> <p>Whitespace around dot-separated parts is ignored, however, best practice is to not use any extraneous whitespace.</p> <p>Defining a key multiple times is invalid.</p> <pre><code data-controller="snippet" class="language-toml"># DO NOT DO THIS name = "Tom" name = "Pradyun"</code></pre> <p>Note that bare keys and quoted keys are equivalent:</p> <pre><code data-controller="snippet" class="language-toml"># THIS WILL NOT WORK spelling = "favorite" "spelling" = "favourite"</code></pre> <p>As long as a key hasn't been directly defined, you may still write to it and to names within it.</p> <pre><code data-controller="snippet" class="language-toml"># This makes the key "fruit" into a table. fruit.apple.smooth = true # So then you can add to the table "fruit" like so: fruit.orange = 2</code></pre> <pre><code data-controller="snippet" class="language-toml"># THE FOLLOWING IS INVALID # This defines the value of fruit.apple to be an integer. fruit.apple = 1 # But then this treats fruit.apple like it's a table. # You can't turn an integer into a table. fruit.apple.smooth = true</code></pre> <p>Defining dotted keys out-of-order is discouraged.</p> <pre><code data-controller="snippet" class="language-toml"># VALID BUT DISCOURAGED apple.type = "fruit" orange.type = "fruit" apple.skin = "thin" orange.skin = "thick" apple.color = "red" orange.color = "orange"</code></pre> <pre><code data-controller="snippet" class="language-toml"># RECOMMENDED apple.type = "fruit" apple.skin = "thin" apple.color = "red" orange.type = "fruit" orange.skin = "thick" orange.color = "orange"</code></pre> <p>Since bare keys are allowed to compose of only ASCII integers, it is possible to write dotted keys that look like floats but are 2-part dotted keys. Don't do this unless you have a good reason to (you probably don't).</p> <pre><code data-controller="snippet" class="language-toml">3.14159 = "pi"</code></pre> <p>The above TOML maps to the following JSON.</p> <pre><code data-controller="snippet" class="language-json">{ "3": { "14159": "pi" } }</code></pre> <h2 id="string" data-target="nav.header"> <a href="#string">String</a> </h2> <p>There are four ways to express strings: basic, multi-line basic, literal, and multi-line literal. All strings must contain only valid UTF-8 characters.</p> <p><strong>Basic strings</strong> are surrounded by quotation marks (<code>"</code>). Any Unicode character may be used except those that must be escaped: quotation mark, backslash, and the control characters other than tab (U+0000 to U+0008, U+000A to U+001F, U+007F).</p> <pre><code data-controller="snippet" class="language-toml">str = "I'm a string. \"You can quote me\". Name\tJos\u00E9\nLocation\tSF."</code></pre> <p>For convenience, some popular characters have a compact escape sequence.</p> <pre><code data-controller="snippet" class="language-toml">\b - backspace (U+0008) \t - tab (U+0009) \n - linefeed (U+000A) \f - form feed (U+000C) \r - carriage return (U+000D) \" - quote (U+0022) \\ - backslash (U+005C) \uXXXX - unicode (U+XXXX) \UXXXXXXXX - unicode (U+XXXXXXXX)</code></pre> <p>Any Unicode character may be escaped with the <code>\uXXXX</code> or <code>\UXXXXXXXX</code> forms. The escape codes must be valid Unicode <a href="http://unicode.org/glossary/#unicode_scalar_value">scalar values</a>.</p> <p>All other escape sequences not listed above are reserved; if they are used, TOML should produce an error.</p> <p>Sometimes you need to express passages of text (e.g. translation files) or would like to break up a very long string into multiple lines. TOML makes this easy.</p> <p><strong>Multi-line basic strings</strong> are surrounded by three quotation marks on each side and allow newlines. A newline immediately following the opening delimiter will be trimmed. All other whitespace and newline characters remain intact.</p> <pre><code data-controller="snippet" class="language-toml">str1 = """ Roses are red Violets are blue"""</code></pre> <p>TOML parsers should feel free to normalize newline to whatever makes sense for their platform.</p> <pre><code data-controller="snippet" class="language-toml"># On a Unix system, the above multi-line string will most likely be the same as: str2 = "Roses are red\nViolets are blue" # On a Windows system, it will most likely be equivalent to: str3 = "Roses are red\r\nViolets are blue"</code></pre> <p>For writing long strings without introducing extraneous whitespace, use a "line ending backslash". When the last non-whitespace character on a line is an unescaped <code>\</code>, it will be trimmed along with all whitespace (including newlines) up to the next non-whitespace character or closing delimiter. All of the escape sequences that are valid for basic strings are also valid for multi-line basic strings.</p> <pre><code data-controller="snippet" class="language-toml"># The following strings are byte-for-byte equivalent: str1 = "The quick brown fox jumps over the lazy dog." str2 = """ The quick brown \ fox jumps over \ the lazy dog.""" str3 = """\ The quick brown \ fox jumps over \ the lazy dog.\ """</code></pre> <p>Any Unicode character may be used except those that must be escaped: backslash and the control characters other than tab, line feed, and carriage return (U+0000 to U+0008, U+000B, U+000C, U+000E to U+001F, U+007F).</p> <p>You can write a quotation mark, or two adjacent quotation marks, anywhere inside a multi-line basic string. They can also be written just inside the delimiters.</p> <pre><code data-controller="snippet" class="language-toml">str4 = """Here are two quotation marks: "". Simple enough.""" # str5 = """Here are three quotation marks: """.""" # INVALID str5 = """Here are three quotation marks: ""\".""" str6 = """Here are fifteen quotation marks: ""\"""\"""\"""\"""\".""" # "This," she said, "is just a pointless statement." str7 = """"This," she said, "is just a pointless statement.""""</code></pre> <p>If you're a frequent specifier of Windows paths or regular expressions, then having to escape backslashes quickly becomes tedious and error-prone. To help, TOML supports literal strings which do not allow escaping at all.</p> <p><strong>Literal strings</strong> are surrounded by single quotes. Like basic strings, they must appear on a single line:</p> <pre><code data-controller="snippet" class="language-toml"># What you see is what you get. winpath = 'C:\Users\nodejs\templates' winpath2 = '\\ServerX\admin$\system32\' quoted = 'Tom "Dubs" Preston-Werner' regex = '<\i\c*\s*>'</code></pre> <p>Since there is no escaping, there is no way to write a single quote inside a literal string enclosed by single quotes. Luckily, TOML supports a multi-line version of literal strings that solves this problem.</p> <p><strong>Multi-line literal strings</strong> are surrounded by three single quotes on each side and allow newlines. Like literal strings, there is no escaping whatsoever. A newline immediately following the opening delimiter will be trimmed. All other content between the delimiters is interpreted as-is without modification.</p> <pre><code data-controller="snippet" class="language-toml">regex2 = '''I [dw]on't need \d{2} apples''' lines = ''' The first newline is trimmed in raw strings. All other whitespace is preserved. '''</code></pre> <p>You can write 1 or 2 single quotes anywhere within a multi-line literal string, but sequences of three or more single quotes are not permitted.</p> <pre><code data-controller="snippet" class="language-toml">quot15 = '''Here are fifteen quotation marks: """""""""""""""''' # apos15 = '''Here are fifteen apostrophes: '''''''''''''''''' # INVALID apos15 = "Here are fifteen apostrophes: '''''''''''''''" # 'That,' she said, 'is still pointless.' str = ''''That,' she said, 'is still pointless.''''</code></pre> <p>Control characters other than tab are not permitted in a literal string. Thus, for binary data, it is recommended that you use Base64 or another suitable ASCII or UTF-8 encoding. The handling of that encoding will be application-specific.</p> <h2 id="integer" data-target="nav.header"> <a href="#integer">Integer</a> </h2> <p>Integers are whole numbers. Positive numbers may be prefixed with a plus sign. Negative numbers are prefixed with a minus sign.</p> <pre><code data-controller="snippet" class="language-toml">int1 = +99 int2 = 42 int3 = 0 int4 = -17</code></pre> <p>For large numbers, you may use underscores between digits to enhance readability. Each underscore must be surrounded by at least one digit on each side.</p> <pre><code data-controller="snippet" class="language-toml">int5 = 1_000 int6 = 5_349_221 int7 = 53_49_221 # Indian number system grouping int8 = 1_2_3_4_5 # VALID but discouraged</code></pre> <p>Leading zeros are not allowed. Integer values <code>-0</code> and <code>+0</code> are valid and identical to an unprefixed zero.</p> <p>Non-negative integer values may also be expressed in hexadecimal, octal, or binary. In these formats, leading <code>+</code> is not allowed and leading zeros are allowed (after the prefix). Hex values are case-insensitive. Underscores are allowed between digits (but not between the prefix and the value).</p> <pre><code data-controller="snippet" class="language-toml"># hexadecimal with prefix `0x` hex1 = 0xDEADBEEF hex2 = 0xdeadbeef hex3 = 0xdead_beef # octal with prefix `0o` oct1 = 0o01234567 oct2 = 0o755 # useful for Unix file permissions # binary with prefix `0b` bin1 = 0b11010110</code></pre> <p>Arbitrary 64-bit signed integers (from −2^63 to 2^63−1) should be accepted and handled losslessly. If an integer cannot be represented losslessly, an error must be thrown.</p> <h2 id="float" data-target="nav.header"> <a href="#float">Float</a> </h2> <p>Floats should be implemented as IEEE 754 binary64 values.</p> <p>A float consists of an integer part (which follows the same rules as decimal integer values) followed by a fractional part and/or an exponent part. If both a fractional part and exponent part are present, the fractional part must precede the exponent part.</p> <pre><code data-controller="snippet" class="language-toml"># fractional flt1 = +1.0 flt2 = 3.1415 flt3 = -0.01 # exponent flt4 = 5e+22 flt5 = 1e06 flt6 = -2E-2 # both flt7 = 6.626e-34</code></pre> <p>A fractional part is a decimal point followed by one or more digits.</p> <p>An exponent part is an E (upper or lower case) followed by an integer part (which follows the same rules as decimal integer values but may include leading zeros).</p> <p>The decimal point, if used, must be surrounded by at least one digit on each side.</p> <pre><code data-controller="snippet" class="language-toml"># INVALID FLOATS invalid_float_1 = .7 invalid_float_2 = 7. invalid_float_3 = 3.e+20</code></pre> <p>Similar to integers, you may use underscores to enhance readability. Each underscore must be surrounded by at least one digit.</p> <pre><code data-controller="snippet" class="language-toml">flt8 = 224_617.445_991_228</code></pre> <p>Float values <code>-0.0</code> and <code>+0.0</code> are valid and should map according to IEEE 754.</p> <p>Special float values can also be expressed. They are always lowercase.</p> <pre><code data-controller="snippet" class="language-toml"># infinity sf1 = inf # positive infinity sf2 = +inf # positive infinity sf3 = -inf # negative infinity # not a number sf4 = nan # actual sNaN/qNaN encoding is implementation-specific sf5 = +nan # same as `nan` sf6 = -nan # valid, actual encoding is implementation-specific</code></pre> <h2 id="boolean" data-target="nav.header"> <a href="#boolean">Boolean</a> </h2> <p>Booleans are just the tokens you're used to. Always lowercase.</p> <pre><code data-controller="snippet" class="language-toml">bool1 = true bool2 = false</code></pre> <h2 id="offset-date-time" data-target="nav.header"> <a href="#offset-date-time">Offset Date-Time</a> </h2> <p>To unambiguously represent a specific instant in time, you may use an <a href="http://tools.ietf.org/html/rfc3339">RFC 3339</a> formatted date-time with offset.</p> <pre><code data-controller="snippet" class="language-toml">odt1 = 1979-05-27T07:32:00Z odt2 = 1979-05-27T00:32:00-07:00 odt3 = 1979-05-27T00:32:00.999999-07:00</code></pre> <p>For the sake of readability, you may replace the T delimiter between date and time with a space character (as permitted by RFC 3339 section 5.6).</p> <pre><code data-controller="snippet" class="language-toml">odt4 = 1979-05-27 07:32:00Z</code></pre> <p>Millisecond precision is required. Further precision of fractional seconds is implementation-specific. If the value contains greater precision than the implementation can support, the additional precision must be truncated, not rounded.</p> <h2 id="local-date-time" data-target="nav.header"> <a href="#local-date-time">Local Date-Time</a> </h2> <p>If you omit the offset from an <a href="http://tools.ietf.org/html/rfc3339">RFC 3339</a> formatted date-time, it will represent the given date-time without any relation to an offset or timezone. It cannot be converted to an instant in time without additional information. Conversion to an instant, if required, is implementation-specific.</p> <pre><code data-controller="snippet" class="language-toml">ldt1 = 1979-05-27T07:32:00 ldt2 = 1979-05-27T00:32:00.999999</code></pre> <p>Millisecond precision is required. Further precision of fractional seconds is implementation-specific. If the value contains greater precision than the implementation can support, the additional precision must be truncated, not rounded.</p> <h2 id="local-date" data-target="nav.header"> <a href="#local-date">Local Date</a> </h2> <p>If you include only the date portion of an <a href="http://tools.ietf.org/html/rfc3339">RFC 3339</a> formatted date-time, it will represent that entire day without any relation to an offset or timezone.</p> <pre><code data-controller="snippet" class="language-toml">ld1 = 1979-05-27</code></pre> <h2 id="local-time" data-target="nav.header"> <a href="#local-time">Local Time</a> </h2> <p>If you include only the time portion of an <a href="http://tools.ietf.org/html/rfc3339">RFC 3339</a> formatted date-time, it will represent that time of day without any relation to a specific day or any offset or timezone.</p> <pre><code data-controller="snippet" class="language-toml">lt1 = 07:32:00 lt2 = 00:32:00.999999</code></pre> <p>Millisecond precision is required. Further precision of fractional seconds is implementation-specific. If the value contains greater precision than the implementation can support, the additional precision must be truncated, not rounded.</p> <h2 id="array" data-target="nav.header"> <a href="#array">Array</a> </h2> <p>Arrays are square brackets with values inside. Whitespace is ignored. Elements are separated by commas. Arrays can contain values of the same data types as allowed in key/value pairs. Values of different types may be mixed.</p> <pre><code data-controller="snippet" class="language-toml">integers = [ 1, 2, 3 ] colors = [ "red", "yellow", "green" ] nested_array_of_int = [ [ 1, 2 ], [3, 4, 5] ] nested_mixed_array = [ [ 1, 2 ], ["a", "b", "c"] ] string_array = [ "all", 'strings', """are the same""", '''type''' ] # Mixed-type arrays are allowed numbers = [ 0.1, 0.2, 0.5, 1, 2, 5 ] contributors = [ "Foo Bar <foo@example.com>", { name = "Baz Qux", email = "bazqux@example.com", url = "https://example.com/bazqux" } ]</code></pre> <p>Arrays can span multiple lines. A terminating comma (also called trailing comma) is ok after the last value of the array. There can be an arbitrary number of newlines and comments before a value and before the closing bracket.</p> <pre><code data-controller="snippet" class="language-toml">integers2 = [ 1, 2, 3 ] integers3 = [ 1, 2, # this is ok ]</code></pre> <h2 id="table" data-target="nav.header"> <a href="#table">Table</a> </h2> <p>Tables (also known as hash tables or dictionaries) are collections of key/value pairs. They appear in square brackets on a line by themselves. You can tell them apart from arrays because arrays are only ever values.</p> <pre><code data-controller="snippet" class="language-toml">[table]</code></pre> <p>Under that, and until the next table or EOF are the key/values of that table. Key/value pairs within tables are not guaranteed to be in any specific order.</p> <pre><code data-controller="snippet" class="language-toml">[table-1] key1 = "some string" key2 = 123 [table-2] key1 = "another string" key2 = 456</code></pre> <p>Naming rules for tables are the same as for keys (see definition of <a href="#keys">Keys</a> above).</p> <pre><code data-controller="snippet" class="language-toml">[dog."tater.man"] type.name = "pug"</code></pre> <p>In JSON land, that would give you the following structure:</p> <pre><code data-controller="snippet" class="language-json">{ "dog": { "tater.man": { "type": { "name": "pug" } } } }</code></pre> <p>Whitespace around the key is ignored, however, best practice is to not use any extraneous whitespace.</p> <pre><code data-controller="snippet" class="language-toml">[a.b.c] # this is best practice [ d.e.f ] # same as [d.e.f] [ g . h . i ] # same as [g.h.i] [ j . "ʞ" . 'l' ] # same as [j."ʞ".'l']</code></pre> <p>You don't need to specify all the super-tables if you don't want to. TOML knows how to do it for you.</p> <pre><code data-controller="snippet" class="language-toml"># [x] you # [x.y] don't # [x.y.z] need these [x.y.z.w] # for this to work [x] # defining a super-table afterward is ok</code></pre> <p>Empty tables are allowed and simply have no key/value pairs within them.</p> <p>Like keys, you cannot define a table more than once. Doing so is invalid.</p> <pre><code data-controller="snippet" class="language-toml"># DO NOT DO THIS [fruit] apple = "red" [fruit] orange = "orange"</code></pre> <pre><code data-controller="snippet" class="language-toml"># DO NOT DO THIS EITHER [fruit] apple = "red" [fruit.apple] texture = "smooth"</code></pre> <p>Defining tables out-of-order is discouraged.</p> <pre><code data-controller="snippet" class="language-toml"># VALID BUT DISCOURAGED [fruit.apple] [animal] [fruit.orange]</code></pre> <pre><code data-controller="snippet" class="language-toml"># RECOMMENDED [fruit.apple] [fruit.orange] [animal]</code></pre> <p>Dotted keys define everything to the left of each dot as a table. Since tables cannot be defined more than once, redefining such tables using a <code>[table]</code> header is not allowed. Likewise, using dotted keys to redefine tables already defined in <code>[table]</code> form is not allowed.</p> <p>The <code>[table]</code> form can, however, be used to define sub-tables within tables defined via dotted keys.</p> <pre><code data-controller="snippet" class="language-toml">[fruit] apple.color = "red" apple.taste.sweet = true # [fruit.apple] # INVALID # [fruit.apple.taste] # INVALID [fruit.apple.texture] # you can add sub-tables smooth = true</code></pre> <h2 id="inline-table" data-target="nav.header"> <a href="#inline-table">Inline Table</a> </h2> <p>Inline tables provide a more compact syntax for expressing tables. They are especially useful for grouped data that can otherwise quickly become verbose. Inline tables are enclosed in curly braces: <code>{</code> and <code>}</code>. Within the braces, zero or more comma-separated key/value pairs may appear. Key/value pairs take the same form as key/value pairs in standard tables. All value types are allowed, including inline tables.</p> <p>Inline tables are intended to appear on a single line. A terminating comma (also called trailing comma) is not permitted after the last key/value pair in an inline table. No newlines are allowed between the curly braces unless they are valid within a value. Even so, it is strongly discouraged to break an inline table onto multiples lines. If you find yourself gripped with this desire, it means you should be using standard tables.</p> <pre><code data-controller="snippet" class="language-toml">name = { first = "Tom", last = "Preston-Werner" } point = { x = 1, y = 2 } animal = { type.name = "pug" }</code></pre> <p>The inline tables above are identical to the following standard table definitions:</p> <pre><code data-controller="snippet" class="language-toml">[name] first = "Tom" last = "Preston-Werner" [point] x = 1 y = 2 [animal] type.name = "pug"</code></pre> <p>Inline tables fully define the keys and sub-tables within them. New keys and sub-tables cannot be added to them.</p> <pre><code data-controller="snippet" class="language-toml">[product] type = { name = "Nail" } # type.edible = false # INVALID</code></pre> <p>Similarly, inline tables can not be used to add keys or sub-tables to an already-defined table.</p> <pre><code data-controller="snippet" class="language-toml">[product] type.name = "Nail" # type = { edible = false } # INVALID</code></pre> <h2 id="array-of-tables" data-target="nav.header"> <a href="#array-of-tables">Array of Tables</a> </h2> <p>The last syntax that has not yet been described allows writing arrays of tables. These can be expressed by using a table name in double brackets. Under that, and until the next table or EOF are the key/values of that table. Each table with the same double bracketed name will be an element in the array of tables. The tables are inserted in the order encountered. A double bracketed table without any key/value pairs will be considered an empty table.</p> <pre><code data-controller="snippet" class="language-toml">[[products]] name = "Hammer" sku = 738594937 [[products]] [[products]] name = "Nail" sku = 284758393 color = "gray"</code></pre> <p>In JSON land, that would give you the following structure.</p> <pre><code data-controller="snippet" class="language-json">{ "products": [ { "name": "Hammer", "sku": 738594937 }, { }, { "name": "Nail", "sku": 284758393, "color": "gray" } ] }</code></pre> <p>You can create nested arrays of tables as well. Just use the same double bracket syntax on sub-tables. In nested arrays of tables, each double-bracketed sub-table will belong to the most recently defined table element. Normal sub-tables (not arrays) likewise belong to the most recently defined table element.</p> <pre><code data-controller="snippet" class="language-toml">[[fruit]] name = "apple" [fruit.physical] # subtable color = "red" shape = "round" [[fruit.variety]] # nested array of tables name = "red delicious" [[fruit.variety]] name = "granny smith" [[fruit]] name = "banana" [[fruit.variety]] name = "plantain"</code></pre> <p>The above TOML maps to the following JSON.</p> <pre><code data-controller="snippet" class="language-json">{ "fruit": [ { "name": "apple", "physical": { "color": "red", "shape": "round" }, "variety": [ { "name": "red delicious" }, { "name": "granny smith" } ] }, { "name": "banana", "variety": [ { "name": "plantain" } ] } ] }</code></pre> <p>If the parent of a table or array of tables is an array element, that element must already have been defined before the child can be defined. Attempts to reverse that ordering must produce an error at parse time.</p> <pre><code data-controller="snippet" class="language-toml"># INVALID TOML DOC [fruit.physical] # subtable, but to which parent element should it belong? color = "red" shape = "round" [[fruit]] # parser must throw an error upon discovering that "fruit" is # an array rather than a table name = "apple"</code></pre> <p>Attempting to append to a statically defined array, even if that array is empty, must produce an error at parse time.</p> <pre><code data-controller="snippet" class="language-toml"># INVALID TOML DOC fruit = [] [[fruit]] # Not allowed</code></pre> <p>Attempting to define a normal table with the same name as an already established array must produce an error at parse time. Attempting to redefine a normal table as an array must likewise produce a parse-time error.</p> <pre><code data-controller="snippet" class="language-toml"># INVALID TOML DOC [[fruit]] name = "apple" [[fruit.variety]] name = "red delicious" # INVALID: This table conflicts with the previous array of tables [fruit.variety] name = "granny smith" [fruit.physical] color = "red" shape = "round" # INVALID: This array of tables conflicts with the previous table [[fruit.physical]] color = "green"</code></pre> <p>You may also use inline tables where appropriate:</p> <pre><code data-controller="snippet" class="language-toml">points = [ { x = 1, y = 2, z = 3 }, { x = 7, y = 8, z = 9 }, { x = 2, y = 4, z = 8 } ]</code></pre> <h2 id="filename-extension" data-target="nav.header"> <a href="#filename-extension">Filename Extension</a> </h2> <p>TOML files should use the extension <code>.toml</code>.</p> <h2 id="mime-type" data-target="nav.header"> <a href="#mime-type">MIME Type</a> </h2> <p>When transferring TOML files over the internet, the appropriate MIME type is <code>application/toml</code>.</p> </div> </main> </div> </div> </body> </html>

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