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6.13.3 Conditional Evaluation of a Sequence of Expressions
and
and or
evaluate all their arguments in order, similar
to begin
, but evaluation stops as soon as one of the expressions
evaluates to false or true, respectively.
- syntax: and expr …
Evaluate the exprs from left to right and stop evaluation as soon as one expression evaluates to
#f
; the remaining expressions are not evaluated. The value of the last evaluated expression is returned. If no expression evaluates to#f
, the value of the last expression is returned.If used without expressions,
#t
is returned.
- syntax: or expr …
Evaluate the exprs from left to right and stop evaluation as soon as one expression evaluates to a true value (that is, a value different from
#f
); the remaining expressions are not evaluated. The value of the last evaluated expression is returned. If all expressions evaluate to#f
,#f
is returned.If used without expressions,
#f
is returned.
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