🚀 go-pugleaf

In article  <1989Aug14.022903.22953@agate.berkeley.edu> mwm@eris.berkeley.edu (Mike (I'll think of something yet) Meyer) writes:
[summary: in Icon, (1) a relational operator "fails" if the relation
does not hold, and produces the value of the right operand if the
relation holds.  (2) if one argument to an operation fails, the whole
operation fails.  (3) conditional contexts like "if <cond> then" and
"while <cond> do" use failure as false, and any value as "true".]
>
>	if a < b < c < d then
>
>Will work as you'd expect - succeeding only if all the comparisons are
>true. Likewise for:
>
>	if a < b <= c = d < e then

This mechanism has much more far-reaching consequences that just
allowing relational operators to "cascade" properly.  Here are a
couple of other Icon expressions:

i := (i < j)   # assign j to i only if i is less than j

# the | symbol returns the results of both operands, one at a time
if f(i) < (j | k) then ... # if result of f(i) is less than j or k then ...
-- 
					David Gudeman
Department of Computer Science
The University of Arizona        gudeman@arizona.edu
Tucson, AZ 85721                 {allegra,cmcl2,ihnp4,noao}!arizona!gudeman