callback ( head quot: ( callback-env -- ? ) -- ) (original) (raw)

callback ( head quot: ( callback-env -- ? ) -- )

Vocabulary
logic

Inputs

Outputs
None

Word description
Set the quotation to be called. Such quotations take an environment which holds the binding of logic variables, and returns t or f as a result of execution. To retrieve the values of logic variables in the environment, use of or at.

Examples

LOGIC-PRED: N_>_0 { N_>_0 N } [ N of 0 > ] callback

See also
callbacks

Definition

USING: accessors kernel logic.private sequences ;

IN: logic

:: callback ( head quot: ( callback-env -- ? ) -- )
head def>goal :> head-goal head-goal pred>>
[ { head-goal quot } suffix! ] change-defs drop ;