Hello Phil!

29 Oct 95 13:52, Phil Crown wrote to Andrea Zaccagnini:

 AZ>> Awful: I just tested this code, and works fine! Where have
 AZ>> you read about the need for the == operator?

 PC> Just from practicing, the same thing applies in C.

 PC>   =  is an assignment,
 PC>   == checks for equality.

= also functions as a string comparison operator in Rexx.  The difference
between = and == is that = will ignore leading/trailing blanks while ==
requires strict equality. So:

' test' = 'test ' is true.
' test' == 'test ' is false.

== also forces a string comparison w/numeric data, so:

0 = 0.0 is true.
0 == 0.0 is false.

 PC> However, the | and || seem to a bit different in Rexx than in C,
 PC> though I haven't figured out how exactly yet.

| is the logical OR operator and expects boolean arguments, while ||
performs string concatenation. So:

' test' || 'test ' is ' testtest '
and ' test' | 'test ' generates an error in an assignment statement since
Rexx doesn't interpret the strings as boolean values.

Both SAY and REXXTRY do strange (to me, anyway) things when parsing strings
that combine string data and the results of operations that need to be
interpreted on the fly and are not reliable indications of how the data is
interpreted internally by REXX itself when the same operations are
performed as a separate assignment. Oh well, this is price we have to pay
for the convenience of untyped data...strange/incorrect interpretations in
type-specific situations.

.\\ike

--- GoldED/2 2.42.G0615