Bob Nystrom
aa72900a9e
- Delete wren_io.c, wren_io.h, and io.wren source files - Remove multi-arity print overloads and IO.read/IO.time methods - Add System class with print, printAll, write, writeAll methods to core.wren - Update all documentation examples and README to use System.print instead of IO.print
1.2 KiB
1.2 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 {
System.print("The body")
}
It is a runtime error if function is not a function.
Methods
arity
The number of arguments the function requires.
:::dart
System.print(Fn.new {}.arity) // 0.
System.print(Fn.new {|a, b, c| a }.arity) // 3.
call(args...)
Invokes the function with the given arguments.
:::dart
var fn = Fn.new { |arg|
System.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.