Call a function: Difference between revisions

=={{header|Factor}}==

* Calling a word with no arguments:

 

* Calling a word with a fixed number of arguments. This will pull as many objects as it needs from the stack. If there are not enough, it will result in a stack underflow.

 

* No special support for optional arguments.

 

* Variable arguments are achieved by defining a word that takes an integer, and operates on that many items at the top of the stack:

 

* The named arguments idiom is to define a tuple, set its slots, and pass it to a word:

"jack@aol.com" >>from

{ "jill@aol.com" } >>to

"Hello there" >>subject

body >>body

 

* Factor lacks statements; everything is an expression.

 

* First-class context: this pushes a word to the stack. Use execute to evaluate.

Additionally, you can put words directly inside sequences and quotations:

 

* Obtaining the return value, which will be placed on the stack:

 

* Returns true if the word is defined in the Factor VM as opposed to in a vocabulary:

 

* Factor makes no distinction between subroutines and functions. Presumably, a subroutine is just a word which puts nothing on the stack.

 

* Partial application is possible by use of curry. Here, the object 2 is curried into the left side of the quotation (anonymous function) [ - ]:

 

=={{header|Forth}}==