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and
and or
evaluate all their arguments, similar to
begin
, but evaluation stops as soon as one of the expressions
evaluates to false or true, respectively.
and expr ... | syntax |
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, |
or expr ... | syntax |
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, |