// Call a function.\n#list([A], [B])\n\n// Named arguments and trailing\n// content blocks.\n#enum(start: 2)[A][B]\n\n// Version without parentheses.\n#list[A][B]\n![\"Preview\"](\"/en-US-v0.13.1/assets/87cba5b2546c4d8134e4fbb8ab2e42e8.png\")
A mapping from argument values to a return value.
\nYou can call a function by writing a comma-separated list of function\narguments enclosed in parentheses directly after the function name.\nAdditionally, you can pass any number of trailing content blocks arguments\nto a function after the normal argument list. If the normal argument list\nwould become empty, it can be omitted. Typst supports positional and named\narguments. The former are identified by position and type, while the latter\nare written as name: value.
Within math mode, function calls have special behaviour. See the\nmath documentation for more details.
\n// Call a function.\n#list([A], [B])\n\n// Named arguments and trailing\n// content blocks.\n#enum(start: 2)[A][B]\n\n// Version without parentheses.\n#list[A][B]\nFunctions are a fundamental building block of Typst. Typst provides\nfunctions for a variety of typesetting tasks. Moreover, the markup you write\nis backed by functions and all styling happens through functions. This\nreference lists all available functions and how you can use them. Please\nalso refer to the documentation about set and\nshow rules to learn about additional ways you can\nwork with functions in Typst.
\nSome functions are associated with elements like headings or\ntables. When called, these create an element of their respective\nkind. In contrast to normal functions, they can further be used in set\nrules, show rules, and\nselectors.
\nFunctions can hold related definitions in their own scope, similar to a\nmodule. Examples of this are\nassert.eq or list.item. However, this\nfeature is currently only available for built-in functions.
You can define your own function with a let binding\nthat has a parameter list after the binding's name. The parameter list can\ncontain mandatory positional parameters, named parameters with default\nvalues and argument sinks.
\nThe right-hand side of a function binding is the function body, which can be\na block or any other expression. It defines the function's return value and\ncan depend on the parameters. If the function body is a code\nblock, the return value is the result of joining the\nvalues of each expression in the block.
\nWithin a function body, the return keyword can be used to exit early and\noptionally specify a return value. If no explicit return value is given, the\nbody evaluates to the result of joining all expressions preceding the\nreturn.
Functions that don't return any meaningful value return none instead.\nThe return type of such functions is not explicitly specified in the\ndocumentation. (An example of this is array.push).
#let alert(body, fill: red) = {\n set text(white)\n set align(center)\n rect(\n fill: fill,\n inset: 8pt,\n radius: 4pt,\n [*Warning:\\ #body*],\n )\n}\n\n#alert[\n Danger is imminent!\n]\n\n#alert(fill: blue)[\n KEEP OFF TRACKS\n]\n![\"Preview\"](\"/en-US-v0.13.1/assets/e7ac0ae1342dcd1b7bfc1dce40ec5bed.png\")
Functions can be imported from one file (module) into\nanother using import. For example, assume that we have defined the alert\nfunction from the previous example in a file called foo.typ. We can import\nit into another file by writing import "foo.typ": alert.
You can also created an unnamed function without creating a binding by\nspecifying a parameter list followed by => and the function body. If your\nfunction has just one parameter, the parentheses around the parameter list\nare optional. Unnamed functions are mainly useful for show rules, but also\nfor settable properties that take functions like the page function's\nfooter property.
#show "once?": it => [#it #it]\nonce?\n![\"Preview\"](\"/en-US-v0.13.1/assets/c9779efb0fcc717fd4868ec6868bdcf9.png\")
In Typst, all functions are pure. This means that for the same\narguments, they always return the same result. They cannot "remember" things to\nproduce another value when they are called a second time.
\nThe only exception are built-in methods like\narray.push(value). These can modify the values they are\ncalled on.
Returns a new function that has the given arguments pre-applied.
","example":null,"self":true,"params":[{"name":"arguments","details":"The arguments to apply to the function.
","example":null,"types":["any"],"strings":[],"default":null,"positional":true,"named":false,"required":true,"variadic":true,"settable":false}],"returns":["function"],"scope":[]},{"path":["function"],"name":"where","title":"Where","keywords":[],"oneliner":"Returns a selector that filters for elements belonging to this function","element":false,"contextual":false,"deprecation":null,"details":"Returns a selector that filters for elements belonging to this function\nwhose fields have the values of the given arguments.
","example":"#show heading.where(level: 2): set text(blue)\n= Section\n== Subsection\n=== Sub-subsection\n![\"Preview\"](\"/en-US-v0.13.1/assets/54e4780e95888ad47cba40e40c1d918a.png\")
The fields to filter for.
","example":null,"types":["any"],"strings":[],"default":null,"positional":true,"named":false,"required":true,"variadic":true,"settable":false}],"returns":["selector"],"scope":[]}]}}}