Bob Nystrom
e19ff59cce
Replace all uses of the `new` reserved word with explicit `this new()` constructor definitions and `ClassName.new()` instantiation calls in builtin/core.wren. Update all documentation files (classes.markdown, fiber.markdown, fn.markdown, sequence.markdown, error-handling.markdown, expressions.markdown, fibers.markdown, functions.markdown) to reflect the new constructor syntax, removing `new` keyword examples and replacing them with `ClassName.new()` patterns and `this new()` definitions.
1.1 KiB
1.1 KiB
^title Fn Class ^category core
A first class function—an object that wraps an executable chunk of code. Here is a friendly introduction.
Fn.new(function)
Creates a new function from... function. Of course, function is already a
function, so this really just returns the argument. It exists mainly to let you
create a "bare" function when you don't want to immediately pass it as a block
argument to some other method.
:::dart
var fn = Fn.new {
IO.print("The body")
}
It is a runtime error if function is not a function.
Methods
arity
The number of arguments the function requires.
:::dart
IO.print(Fn.new {}.arity) // 0.
IO.print(Fn.new {|a, b, c| a }.arity) // 3.
call(args...)
Invokes the function with the given arguments.
:::dart
var fn = Fn.new { |arg|
IO.print(arg)
}
fn.call("Hello world") // Prints "Hello world".
It is a runtime error if the number of arguments given is less than the arity of the function. If more arguments are given than the function's arity they are ignored.