alist>quot ( default assoc -- quot )

alist>quot ( default assoc -- quot )
Factor handbook » The language » Combinators » Quotation construction utilities

Vocabulary
combinators

Inputs

default	a quotation
assoc	a sequence of quotation pairs

Outputs

quot	a new quotation

Word description
Constructs a quotation which calls the first quotation in each pair of assoc until one of them outputs a true value, and then calls the second quotation in the corresponding pair. Quotations are called in reverse order, and if no quotation outputs a true value then default is called.

Notes
This word is used to implement compile-time behavior for cond, and it is also used by the generic word system. Note that unlike cond, the constructed quotation performs the tests starting from the end and not the beginning.

Definition

USING: arrays assocs kernel sequences ;

IN: combinators

: alist>quot ( default assoc -- quot )
[ rot \ if 3array append [ ] like ] assoc-each ;