Node:and or, Next:while do, Previous:if cond case, Up:Control Mechanisms
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, |