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# Standard Library

This page describes the functions available in Jsonnet's standard library, i.e. the object implicitly bound to the `std` variable. Some of the standard library functions can be implemented in Jsonnet. Their code can be found in the `std.jsonnet` file. The behavior of some of the other functions, i.e. the ones that expose extra functionality not otherwise available to programmers, is described formally in the specification.

The standard library is implicitly added to all Jsonnet programs by enclosing them in a local construct. For example, if the program given by the user is `{x: "foo"}`, then the actual code executed would be `local std = { ... }; {x: "foo"}`. The functions in the standard library are all hidden fields of the `std` object.

Note: Some of these functions marked available since v0.10.0 were actually available earlier.

### External Variables

#### std.extVar(x)

Available since version 0.10.0.

If an external variable with the given name was defined, return its string value. Otherwise, raise an error.

### Types and Reflection

#### std.thisFile

Available since version 0.10.0.

Note that this is a field. It contains the current Jsonnet filename as a string.

#### std.type(x)

Available since version 0.10.0.

Return a string that indicates the type of the value. The possible return values are: "array", "boolean", "function", "null", "number", "object", and "string".

The following functions are also available and return a boolean: `std.isArray(v)`, `std.isBoolean(v)`, `std.isFunction(v)`, `std.isNumber(v)`, `std.isObject(v)`, and `std.isString(v)`.

#### std.length(x)

Available since version 0.10.0.

Depending on the type of the value given, either returns the number of elements in the array, the number of codepoints in the string, the number of parameters in the function, or the number of fields in the object. Raises an error if given a primitive value, i.e. `null`, `true` or `false`.

#### std.get(o, f, default=null, inc_hidden=true)

Available since version 0.18.0.

Returns the object's field if it exists or default value otherwise. `inc_hidden` controls whether to include hidden fields.

#### std.objectHas(o, f)

Available since version 0.10.0.

Returns `true` if the given object has the field (given as a string), otherwise `false`. Raises an error if the arguments are not object and string respectively. Returns false if the field is hidden.

#### std.objectFields(o)

Available since version 0.10.0.

Returns an array of strings, each element being a field from the given object. Does not include hidden fields.

#### std.objectValues(o)

Available since version 0.17.0.

Returns an array of the values in the given object. Does not include hidden fields.

#### std.objectKeysValues(o)

Available in upcoming release.

Returns an array of objects from the given object, each object having two fields: `key` (string) and `value` (object). Does not include hidden fields.

#### std.objectHasAll(o, f)

Available since version 0.10.0.

As `std.objectHas` but also includes hidden fields.

#### std.objectFieldsAll(o)

Available since version 0.10.0.

As `std.objectFields` but also includes hidden fields.

#### std.objectValuesAll(o)

Available since version 0.17.0.

As `std.objectValues` but also includes hidden fields.

#### std.objectKeysValuesAll(o)

Available in upcoming release.

As `std.objectKeysValues` but also includes hidden fields.

#### std.prune(a)

Available since version 0.10.0.

Recursively remove all "empty" members of `a`. "Empty" is defined as zero length `arrays`, zero length `objects`, or `null` values. The argument `a` may have any type.

#### std.mapWithKey(func, obj)

Available since version 0.10.0.

Apply the given function to all fields of the given object, also passing the field name. The function `func` is expected to take the field name as the first parameter and the field value as the second.

### Mathematical Utilities

The following mathematical functions are available:

`std.abs(n)`

`std.sign(n)`

`std.max(a, b)`

`std.min(a, b)`

`std.pow(x, n)`

`std.exp(x)`

`std.log(x)`

`std.exponent(x)`

`std.mantissa(x)`

`std.floor(x)`

`std.ceil(x)`

`std.sqrt(x)`

`std.sin(x)`

`std.cos(x)`

`std.tan(x)`

`std.asin(x)`

`std.acos(x)`

`std.atan(x)`

`std.round(x)`

The function `std.mod(a, b)` is what the % operator is desugared to. It performs modulo arithmetic if the left hand side is a number, or if the left hand side is a string, it does Python-style string formatting with `std.format()`.

#### std.clamp(x, minVal, maxVal)

Available since version 0.15.0.

Clamp a value to fit within the range [`minVal`, `maxVal`]. Equivalent to `std.max(minVal, std.min(x, maxVal))`.

Example: `std.clamp(-3, 0, 5)` yields `0`.

Example: `std.clamp(4, 0, 5)` yields `4`.

Example: `std.clamp(7, 0, 5)` yields `5`.

### Assertions and Debugging

#### std.assertEqual(a, b)

Available since version 0.10.0.

Ensure that `a == b`. Returns `true` or throws an error message.

### String Manipulation

#### std.toString(a)

Available since version 0.10.0.

Convert the given argument to a string.

#### std.codepoint(str)

Available since version 0.10.0.

Returns the positive integer representing the unicode codepoint of the character in the given single-character string. This function is the inverse of `std.char(n)`.

#### std.char(n)

Available since version 0.10.0.

Returns a string of length one whose only unicode codepoint has integer id `n`. This function is the inverse of `std.codepoint(str)`.

#### std.substr(str, from, len)

Available since version 0.10.0.

Returns a string that is the part of `s` that starts at offset `from` and is `len` codepoints long. If the string `s` is shorter than `from+len`, the suffix starting at position `from` will be returned.

#### std.findSubstr(pat, str)

Available since version 0.10.0.

Returns an array that contains the indexes of all occurrences of `pat` in `str`.

#### std.startsWith(a, b)

Available since version 0.10.0.

Returns whether the string a is prefixed by the string b.

#### std.endsWith(a, b)

Available since version 0.10.0.

Returns whether the string a is suffixed by the string b.

#### std.stripChars(str, chars)

Available since version 0.15.0.

Removes characters `chars` from the beginning and from the end of `str`.

Example: `std.stripChars(" test test test ", " ")` yields `"test test test"`.

Example: `std.stripChars("aaabbbbcccc", "ac")` yields `"bbbb"`.

Example: `std.stripChars("cacabbbbaacc", "ac")` yields `"bbbb"`.

#### std.lstripChars(str, chars)

Available since version 0.15.0.

Removes characters `chars` from the beginning of `str`.

Example: `std.lstripChars(" test test test ", " ")` yields `"test test test "`.

Example: `std.lstripChars("aaabbbbcccc", "ac")` yields `"bbbbcccc"`.

Example: `std.lstripChars("cacabbbbaacc", "ac")` yields `"bbbbaacc"`.

#### std.rstripChars(str, chars)

Available since version 0.15.0.

Removes characters `chars` from the end of `str`.

Example: `std.rstripChars(" test test test ", " ")` yields `" test test test"`.

Example: `std.rstripChars("aaabbbbcccc", "ac")` yields `"aaabbbb"`.

Example: `std.rstripChars("cacabbbbaacc", "ac")` yields `"cacabbbb"`.

#### std.split(str, c)

Available since version 0.10.0.

Split the string `str` into an array of strings, divided by the string `c`.

Note: Versions up to and including 0.18.0 require `c` to be a single character.

Example: `std.split("foo/_bar", "/_")` yields `[ "foo", "bar" ]`.

Example: `std.split("/_foo/_bar", "/_")` yields `[ "", "foo", "bar" ]`.

#### std.splitLimit(str, c, maxsplits)

Available since version 0.10.0.

As `std.split(str, c)` but will stop after `maxsplits` splits, thereby the largest array it will return has length `maxsplits + 1`. A limit of `-1` means unlimited.

Note: Versions up to and including 0.18.0 require `c` to be a single character.

Example: `std.splitLimit("foo/_bar", "/_", 1)` yields `[ "foo", "bar" ]`.

Example: `std.splitLimit("/_foo/_bar", "/_", 1)` yields `[ "", "foo/_bar" ]`.

#### std.splitLimitR(str, c, maxsplits)

Available since version 0.19.0.

As `std.splitLimit(str, c, maxsplits)` but will split from right to left.

Example: `std.splitLimitR("/_foo/_bar", "/_", 1)` yields `[ "/_foo", "bar" ]`.

#### std.strReplace(str, from, to)

Available since version 0.10.0.

Returns a copy of the string in which all occurrences of string `from` have been replaced with string `to`.

Example: `std.strReplace('I like to skate with my skateboard', 'skate', 'surf')` yields `"I like to surf with my surfboard"`.

#### std.isEmpty(str)

Available in upcoming release.

Returns true if the the given string is of zero length.

#### std.asciiUpper(str)

Available since version 0.10.0.

Returns a copy of the string in which all ASCII letters are capitalized.

Example: `std.asciiUpper('100 Cats!')` yields `"100 CATS!"`.

#### std.asciiLower(str)

Available since version 0.10.0.

Returns a copy of the string in which all ASCII letters are lower cased.

Example: `std.asciiLower('100 Cats!')` yields `"100 cats!"`.

#### std.stringChars(str)

Available since version 0.10.0.

Split the string `str` into an array of strings, each containing a single codepoint.

Example: `std.stringChars("foo")` yields `[ "f", "o", "o" ]`.

#### std.format(str, vals)

Available since version 0.10.0.

Format the string `str` using the values in `vals`. The values can be an array, an object, or in other cases are treated as if they were provided in a singleton array. The string formatting follows the same rules as Python. The `%` operator can be used as a shorthand for this function.

Example: `std.format("Hello %03d", 12)` yields `"Hello 012"`.

Example: `"Hello %03d" % 12` yields `"Hello 012"`.

Example: `"Hello %s, age %d" % ["Foo", 25]` yields `"Hello Foo, age 25"`.

Example: `"Hello %(name)s, age %(age)d" % {age: 25, name: "Foo"}` yields `"Hello Foo, age 25"`.

#### std.escapeStringBash(str)

Available since version 0.10.0.

Wrap `str` in single quotes, and escape any single quotes within `str` by changing them to a sequence `'"'"'`. This allows injection of arbitrary strings as arguments of commands in bash scripts.

#### std.escapeStringDollars(str)

Available since version 0.10.0.

Convert $ to $$ in `str`. This allows injection of arbitrary strings into systems that use $ for string interpolation (like Terraform).

#### std.escapeStringJson(str)

Available since version 0.10.0.

Convert `str` to allow it to be embedded in a JSON representation, within a string. This adds quotes, escapes backslashes, and escapes unprintable characters.

Example: `local description = "Multiline\nc:\\path"; "{name: %s}" % std.escapeStringJson(description)` yields `"{name: \"Multiline\\nc:\\\\path\"}"`.

#### std.escapeStringPython(str)

Available since version 0.10.0.

Convert `str` to allow it to be embedded in Python. This is an alias for `std.escapeStringJson`.

#### std.escapeStringXml(str)

Available since version 0.10.0.

Convert `str` to allow it to be embedded in XML (or HTML). The following replacements are made:

            {
              "<": "&lt;",
              ">": "&gt;",
              "&": "&amp;",
              "\"": "&quot;",
              "'": "&apos;",
            }

### Parsing

#### std.parseInt(str)

Available since version 0.10.0.

Parses a signed decimal integer from the input string.

Example: `std.parseInt("123")` yields `123`.

Example: `std.parseInt("-123")` yields `-123`.

#### std.parseOctal(str)

Available since version 0.10.0.

Parses an unsigned octal integer from the input string. Initial zeroes are tolerated.

Example: `std.parseOctal("755")` yields `493`.

#### std.parseHex(str)

Available since version 0.10.0.

Parses an unsigned hexadecimal integer, from the input string. Case insensitive.

Example: `std.parseHex("ff")` yields `255`.

#### std.parseJson(str)

Available since version 0.13.0.

Parses a JSON string.

Example: `std.parseJson('{"foo": "bar"}')` yields `{ "foo": "bar" }`.

#### std.parseYaml(str)

Available since version 0.18.0.

Parses a YAML string. This is provided as a "best-effort" mechanism and should not be relied on to provide a fully standards compliant YAML parser. YAML is a superset of JSON, consequently "downcasting" or manifestation of YAML into JSON or Jsonnet values will only succeed when using the subset of YAML that is compatible with JSON. The parser does not support YAML documents with scalar values at the root. The root node of a YAML document must start with either a YAML sequence or map to be successfully parsed.

Example: `std.parseYaml('foo: bar')` yields `{ "foo": "bar" }`.

#### std.encodeUTF8(str)

Available since version 0.13.0.

Encode a string using UTF8. Returns an array of numbers representing bytes.

#### std.decodeUTF8(arr)

Available since version 0.13.0.

Decode an array of numbers representing bytes using UTF8. Returns a string.

### Manifestation

#### std.manifestIni(ini)

Available since version 0.10.0.

Convert the given structure to a string in INI format. This allows using Jsonnet's object model to build a configuration to be consumed by an application expecting an INI file. The data is in the form of a set of sections, each containing a key/value mapping. These examples should make it clear:

    {
        main: { a: "1", b: "2" },
        sections: {
            s1: {x: "11", y: "22", z: "33"},
            s2: {p: "yes", q: ""},
            empty: {},
        }
    }

Yields a string containing this INI file:

    a = 1
    b = 2
    [empty]
    [s1]
    x = 11
    y = 22
    z = 33
    [s2]
    p = yes
    q =

#### std.manifestPython(v)

Available since version 0.10.0.

Convert the given value to a JSON-like form that is compatible with Python. The chief differences are True / False / None instead of true / false / null.

    {
        b: ["foo", "bar"],
        c: true,
        d: null,
        e: { f1: false, f2: 42 },
    }

Yields a string containing Python code like:

    {
        "b": ["foo", "bar"],
        "c": True,
        "d": None,
        "e": {"f1": False, "f2": 42}
    }

#### std.manifestPythonVars(conf)

Available since version 0.10.0.

Convert the given object to a JSON-like form that is compatible with Python. The key difference to `std.manifestPython` is that the top level is represented as a list of Python global variables.

    {
        b: ["foo", "bar"],
        c: true,
        d: null,
        e: { f1: false, f2: 42 },
    }

Yields a string containing this Python code:

    b = ["foo", "bar"]
    c = True
    d = None
    e = {"f1": False, "f2": 42}

#### std.manifestJsonEx(value, indent, newline, key_val_sep)

Available since version 0.10.0.

Convert the given object to a JSON form. `indent` is a string containing one or more whitespaces that are used for indentation. `newline` is by default `\n` and is inserted where a newline would normally be used to break long lines. `key_val_sep` is used to separate the key and value of an object field:

Example: `std.manifestJsonEx( { x: [1, 2, 3, true, false, null, "string\nstring"], y: { a: 1, b: 2, c: [1, 2] }, }, " ")` yields `"{\n \"x\": [\n 1,\n 2,\n 3,\n true,\n false,\n null,\n \"string\\nstring\"\n ],\n \"y\": {\n \"a\": 1,\n \"b\": 2,\n \"c\": [\n 1,\n 2\n ]\n }\n}"`.

Example: `std.manifestJsonEx( { x: [1, 2, "string\nstring"], y: { a: 1, b: [1, 2] }, }, "", " ", " : ")` yields `"{ \"x\" : [ 1, 2, \"string\\nstring\" ], \"y\" : { \"a\" : 1, \"b\" : [ 1, 2 ] } }"`.

#### std.manifestJsonMinified(value)

Available since version 0.18.0.

Convert the given object to a minified JSON form. Under the covers, it calls `std.manifestJsonEx:')`:

Example: `std.manifestJsonMinified( { x: [1, 2, 3, true, false, null, "string\nstring"], y: { a: 1, b: 2, c: [1, 2] }, })` yields `"{\"x\":[1,2,3,true,false,null,\"string\\nstring\"],\"y\":{\"a\":1,\"b\":2,\"c\":[1,2]}}"`.

#### std.manifestYamlDoc(value, indent_array_in_object=false, quote_keys=true)

Available since version 0.10.0.

Convert the given value to a YAML form. Note that `std.manifestJson` could also be used for this purpose, because any JSON is also valid YAML. But this function will produce more canonical-looking YAML.

    std.manifestYamlDoc(
      {
          x: [1, 2, 3, true, false, null,
              "string\nstring\n"],
          y: { a: 1, b: 2, c: [1, 2] },
      },
      indent_array_in_object=false)

Yields a string containing this YAML:

    "x":
      - 1
      - 2
      - 3
      - true
      - false
      - null
      - |
          string
          string
    "y":
      "a": 1
      "b": 2
      "c":
          - 1
          - 2

The `indent_array_in_object` param adds additional indentation which some people may find easier to read.

The `quote_keys` parameter controls whether YAML identifiers are always quoted or only when necessary.

#### std.manifestYamlStream(value, indent_array_in_object=false, c_document_end=false, quote_keys=true)

Available since version 0.10.0.

Given an array of values, emit a YAML "stream", which is a sequence of documents separated by `---` and ending with `...`.

    std.manifestYamlStream(
      ['a', 1, []],
      indent_array_in_object=false,
      c_document_end=true)

Yields this string:

    ---
    "a"
    ---
    1
    ---
    []
    ...

The `indent_array_in_object` and `quote_keys` params are the same as in `manifestYamlDoc`.

The `c_document_end` param adds the optional terminating `...`.

#### std.manifestXmlJsonml(value)

Available since version 0.10.0.

Convert the given JsonML-encoded value to a string containing the XML.

    std.manifestXmlJsonml([
        'svg', { height: 100, width: 100 },
        [
            'circle', {
            cx: 50, cy: 50, r: 40,
            stroke: 'black', 'stroke-width': 3,
            fill: 'red',
            }
        ],
    ])

Yields a string containing this XML (all on one line):

    <svg height="100" width="100">
        <circle cx="50" cy="50" fill="red" r="40"
        stroke="black" stroke-width="3"></circle>;
    </svg>;

Which represents the following image:

JsonML is designed to preserve "mixed-mode content" (i.e., textual data outside of or next to elements). This includes the whitespace needed to avoid having all the XML on one line, which is meaningful in XML. In order to have whitespace in the XML output, it must be present in the JsonML input:

    std.manifestXmlJsonml([
        'svg',
        { height: 100, width: 100 },
        '\n  ',
        [
            'circle',
            {
            cx: 50, cy: 50, r: 40, stroke: 'black',
            'stroke-width': 3, fill: 'red',
            }
        ],
        '\n',
    ])

#### std.manifestTomlEx(toml, indent)

Available since version 0.18.0.

Convert the given object to a TOML form. `indent` is a string containing one or more whitespaces that are used for indentation:

Example: `std.manifestTomlEx({ key1: "value", key2: 1, section: { a: 1, b: "str", c: false, d: [1, "s", [2, 3]], subsection: { k: "v", }, }, sectionArray: [ { k: "v1", v: 123 }, { k: "v2", c: "value2" }, ], }, " ")` yields `"key1 = \"value\"\nkey2 = 1\n\n[section]\n a = 1\n b = \"str\"\n c = false\n d = [\n 1,\n \"s\",\n [ 2, 3 ]\n ]\n\n [section.subsection]\n k = \"v\"\n\n[[sectionArray]]\n k = \"v1\"\n v = 123\n\n[[sectionArray]]\n c = \"value2\"\n k = \"v2\""`.

### Arrays

#### std.makeArray(sz, func)

Available since version 0.10.0.

Create a new array of `sz` elements by calling `func(i)` to initialize each element. Func is expected to be a function that takes a single parameter, the index of the element it should initialize.

Example: `std.makeArray(3,function(x) x * x)` yields `[ 0, 1, 4 ]`.

#### std.member(arr, x)

Available since version 0.15.0.

Returns whether `x` occurs in `arr`. Argument `arr` may be an array or a string.

#### std.count(arr, x)

Available since version 0.10.0.

Return the number of times that `x` occurs in `arr`.

#### std.find(value, arr)

Available since version 0.10.0.

Returns an array that contains the indexes of all occurrences of `value` in `arr`.

#### std.map(func, arr)

Available since version 0.10.0.

Apply the given function to every element of the array to form a new array.

#### std.mapWithIndex(func, arr)

Available since version 0.10.0.

Similar to map above, but it also passes to the function the element's index in the array. The function `func` is expected to take the index as the first parameter and the element as the second.

#### std.filterMap(filter_func, map_func, arr)

Available since version 0.10.0.

It first filters, then maps the given array, using the two functions provided.

#### std.flatMap(func, arr)

Available since version 0.10.0.

Apply the given function to every element of `arr` to form a new array then flatten the result. The argument `arr` must be an array or a string. If `arr` is an array, function `func` must return an array. If `arr` is a string, function `func` must return an string.

The `std.flatMap` function can be thought of as a generalized `std.map`, with each element mapped to 0, 1 or more elements.

Example: `std.flatMap(function(x) [x, x], [1, 2, 3])` yields `[ 1, 1, 2, 2, 3, 3 ]`.

Example: `std.flatMap(function(x) if x == 2 then [] else [x], [1, 2, 3])` yields `[ 1, 3 ]`.

Example: `std.flatMap(function(x) if x == 2 then [] else [x * 3, x * 2], [1, 2, 3])` yields `[ 3, 2, 9, 6 ]`.

Example: `std.flatMap(function(x) x+x, "foo")` yields `"ffoooo"`.

#### std.filter(func, arr)

Available since version 0.10.0.

Return a new array containing all the elements of `arr` for which the `func` function returns true.

#### std.foldl(func, arr, init)

Available since version 0.10.0.

Classic foldl function. Calls the function on the result of the previous function call and each array element, or `init` in the case of the initial element. Traverses the array from left to right.

#### std.foldr(func, arr, init)

Available since version 0.10.0.

Classic foldr function. Calls the function on the result of the previous function call and each array element, or `init` in the case of the initial element. Traverses the array from right to left.

#### std.range(from, to)

Available since version 0.10.0.

Return an array of ascending numbers between the two limits, inclusively.

#### std.repeat(what, count)

Available since version 0.15.0.

Repeats an array or a string `what` a number of times specified by an integer `count`.

Example: `std.repeat([1, 2, 3], 3)` yields `[ 1, 2, 3, 1, 2, 3, 1, 2, 3 ]`.

Example: `std.repeat("blah", 2)` yields `"blahblah"`.

#### std.slice(indexable, index, end, step)

Available since version 0.10.0.

Selects the elements of an array or a string from `index` to `end` with `step` and returns an array or a string respectively.

Note that it's recommended to use dedicated slicing syntax both for arrays and strings (e.g. `arr[0:4:1]` instead of `std.slice(arr, 0, 4, 1)`).

Example: `std.slice([1, 2, 3, 4, 5, 6], 0, 4, 1)` yields `[ 1, 2, 3, 4 ]`.

Example: `std.slice([1, 2, 3, 4, 5, 6], 1, 6, 2)` yields `[ 2, 4, 6 ]`.

Example: `std.slice("jsonnet", 0, 4, 1)` yields `"json"`.

#### std.join(sep, arr)

Available since version 0.10.0.

If `sep` is a string, then `arr` must be an array of strings, in which case they are concatenated with `sep` used as a delimiter. If `sep` is an array, then `arr` must be an array of arrays, in which case the arrays are concatenated in the same way, to produce a single array.

Example: `std.join(".", ["www", "google", "com"])` yields `"www.google.com"`.

Example: `std.join([9, 9], [[1], [2, 3]])` yields `[ 1, 9, 9, 2, 3 ]`.

#### std.lines(arr)

Available since version 0.10.0.

Concatenate an array of strings into a text file with newline characters after each string. This is suitable for constructing bash scripts and the like.

#### std.flattenArrays(arr)

Available since version 0.10.0.

Concatenate an array of arrays into a single array.

Example: `std.flattenArrays([[1, 2], [3, 4], [[5, 6], [7, 8]]])` yields `[ 1, 2, 3, 4, [ 5, 6 ], [ 7, 8 ] ]`.

#### std.reverse(arrs)

Available since version 0.13.0.

Reverses an array.

#### std.sort(arr, keyF=id)

Available since version 0.10.0.

Sorts the array using the <= operator.

Optional argument `keyF` is a single argument function used to extract comparison key from each array element. Default value is identity function `keyF=function(x) x`.

#### std.uniq(arr, keyF=id)

Available since version 0.10.0.

Removes successive duplicates. When given a sorted array, removes all duplicates.

Optional argument `keyF` is a single argument function used to extract comparison key from each array element. Default value is identity function `keyF=function(x) x`.

#### std.all(arr)

Available since version 0.19.0.

Return true if all elements of `arr` is true, false otherwise. `all([])` evaluates to true.

It's an error if 1) `arr` is not an array, or 2) `arr` contains non-boolean values.

#### std.any(arr)

Available since version 0.19.0.

Return true if any element of `arr` is true, false otherwise. `any([])` evaluates to false.

It's an error if 1) `arr` is not an array, or 2) `arr` contains non-boolean values.

#### std.sum(arr)

Available in upcoming release.

Return sum of all element in `arr`.

### Sets

Sets are represented as ordered arrays without duplicates.

Note that the `std.set*` functions rely on the uniqueness and ordering on arrays passed to them to work. This can be guaranteed by using `std.set(arr)`. If that is not the case, the functions will quietly return non-meaningful results.

All `set.set*` functions accept `keyF` function of one argument, which can be used to extract key to use from each element. All Set operations then use extracted key for the purpose of identifying uniqueness. Default value is identity function `local id = function(x) x`.

#### std.set(arr, keyF=id)

Available since version 0.10.0.

Shortcut for std.uniq(std.sort(arr)).

#### std.setInter(a, b, keyF=id)

Available since version 0.10.0.

Set intersection operation (values in both a and b).

#### std.setUnion(a, b, keyF=id)

Available since version 0.10.0.

Set union operation (values in any of `a` or `b`). Note that + on sets will simply concatenate the arrays, possibly forming an array that is not a set (due to not being ordered without duplicates).

Example: `std.setUnion([1, 2], [2, 3])` yields `[ 1, 2, 3 ]`.

Example: `std.setUnion([{n:"A", v:1}, {n:"B"}], [{n:"A", v: 9999}, {n:"C"}], keyF=function(x) x.n)` yields `[ { "n": "A", "v": 1 }, { "n": "B" }, { "n": "C" } ]`.

#### std.setDiff(a, b, keyF=id)

Available since version 0.10.0.

Set difference operation (values in a but not b).

#### std.setMember(x, arr, keyF=id)

Available since version 0.10.0.

Returns `true` if x is a member of array, otherwise `false`.

### Encoding

#### std.base64(input)

Available since version 0.10.0.

Encodes the given value into a base64 string. The encoding sequence is `A-Za-z0-9+/` with `=` to pad the output to a multiple of 4 characters. The value can be a string or an array of numbers, but the codepoints / numbers must be in the 0 to 255 range. The resulting string has no line breaks.

#### std.base64DecodeBytes(str)

Available since version 0.10.0.

Decodes the given base64 string into an array of bytes (number values). Currently assumes the input string has no linebreaks and is padded to a multiple of 4 (with the = character). In other words, it consumes the output of std.base64().

#### std.base64Decode(str)

Available since version 0.10.0.

Deprecated, use `std.base64DecodeBytes` and decode the string explicitly (e.g. with `std.decodeUTF8`) instead.

Behaves like std.base64DecodeBytes() except returns a naively encoded string instead of an array of bytes.

#### std.md5(s)

Available since version 0.10.0.

Encodes the given value into an MD5 string.

### Booleans

#### std.xor(x, y)

Available in upcoming release.

Returns the xor of the two given booleans.

#### std.xnor(x, y)

Available in upcoming release.

Returns the xnor of the two given booleans.

### JSON Merge Patch

#### std.mergePatch(target, patch)

Available since version 0.10.0.

Applies `patch` to `target` according to RFC7396

### Debugging

#### std.trace(str, rest)

Available since version 0.11.0.

Outputs the given string `str` to stderr and returns `rest` as the result.

Example:

    local conditionalReturn(cond, in1, in2) =
      if (cond) then
          std.trace('cond is true returning '
                  + std.toString(in1), in1)
      else
          std.trace('cond is false returning '
                  + std.toString(in2), in2);

    {
        a: conditionalReturn(true, { b: true }, { c: false }),
    }

Prints:

    TRACE: test.jsonnet:3 cond is true returning {"b": true}
    {
        "a": {
            "b": true
        }
    }