src/swipl-devel/packages/xpce/man/refmanual/md/and.md

In rswipl: Embed 'SWI'-'Prolog'

class and {#class-and}

Class and defines a logical and for its associated statements. An and object is not just binary but can have any number of arguments, so one may state

and(Statement1, Statement2, Statement3)

rather then

and(Statement1, and(Statement2, Statement3))

When executed, the and will execute its argument code objects starting from the first. It stops with failure as soon as one of the arguments fails or returns success if all arguments succeed. And objects are both used as a logical connective for conditions (see class if) and as a sequence of statements.

An and object without arguments simply succeeds and is the fastest succeeding code object.

See also class block, class or and class not. Class progn defines a function equivalent of an and.

@see class progn @see topic Conditions

Instance variables {#class-and-instvars}

• and<-members: chain Code objects that are executed in the order they appear in this chain object. All members must be executed successfully. The content of the chain may be modified using the chain-methods, but the user is responsible that all members of the chain are instances of class code.

Send methods {#class-and-send}

• and->_execute Execute the statements of <-members until one fails or the end of the chain is reached. Only in the latter case the and executes successfully.

rswipl documentation built on June 16, 2026, 5:07 p.m.