[PHP] bug in echo function?
I ran across a curious bug in the echo function this morning. My PHP is
Debian binary 4.1.1-1.
The first example below does not work (it should draw a
checkerboard-like table):
-
html
head
titleChess/title
body
table border=1
?
for ($i=0 ; $i8 ; $i++) {
echo tr align=center valign=center;
for ($j=0 ; $j8 ; $j++) {
echo td . ($i*8)+$j . /td;
}
echo /tr\n;
}
?
/table
/body
/html
-
However, by changing the echo line to two echo lines, it works as
desired:
-
html
head
titleChess/title
body
table border=1
?
for ($i=0 ; $i8 ; $i++) {
echo tr align=center valign=center;
for ($j=0 ; $j8 ; $j++) {
echo td;
echo ($i*8)+$j . /td;
}
echo /tr\n;
}
?
/table
/body
/html
-
I don't see any limitations about concatenating strings in the man page
of the echo statement. Perhaps this is a bug?
Billy
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RE: [PHP] bug in echo function?
Good day,
The reason that the first statement doesn't work as intended is due to the
order that the operands are processed.
The operands in the line:
td . ($i*8)+$j . /td
are being processed like this:
(td . ($i*8))+($j . /td)
If you change the line to:
td . (($i*8)+$j) . /td
then you'll get the desired result.
Rule of thumb: Use parenthesis whenever you have a complex operation to
ensure the result is what you want.
Darren Gamble
Planner, Regional Services
Shaw Cablesystems GP
630 - 3rd Avenue SW
Calgary, Alberta, Canada
T2P 4L4
(403) 781-4948
-Original Message-
From: Billy Harvey [mailto:[EMAIL PROTECTED]]
Sent: Friday, January 18, 2002 11:44 AM
To: php
Subject: [PHP] bug in echo function?
I ran across a curious bug in the echo function this morning. My PHP is
Debian binary 4.1.1-1.
The first example below does not work (it should draw a
checkerboard-like table):
-
html
head
titleChess/title
body
table border=1
?
for ($i=0 ; $i8 ; $i++) {
echo tr align=center valign=center;
for ($j=0 ; $j8 ; $j++) {
echo td . ($i*8)+$j . /td;
}
echo /tr\n;
}
?
/table
/body
/html
-
However, by changing the echo line to two echo lines, it works as
desired:
-
html
head
titleChess/title
body
table border=1
?
for ($i=0 ; $i8 ; $i++) {
echo tr align=center valign=center;
for ($j=0 ; $j8 ; $j++) {
echo td;
echo ($i*8)+$j . /td;
}
echo /tr\n;
}
?
/table
/body
/html
-
I don't see any limitations about concatenating strings in the man page
of the echo statement. Perhaps this is a bug?
Billy
--
PHP General Mailing List (http://www.php.net/)
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]
To contact the list administrators, e-mail: [EMAIL PROTECTED]
--
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To unsubscribe, e-mail: [EMAIL PROTECTED]
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RE: [PHP] bug in echo function?
Good day, No, that's not it. It's just a simple matter of order of operations. You have an expression- that expression needs to be evaluated into one thing, and that one thing is then passed to echo() as the single argument. I'm not a php expert, but evidently the . operator is evaluated before the * operator, which in turn is evaluated before the + operator. Perhaps it would be easier to understand if you thought of the . operator like the exponent operator in math- it is evaluated before * or + is. Darren Gamble Planner, Regional Services Shaw Cablesystems GP 630 - 3rd Avenue SW Calgary, Alberta, Canada T2P 4L4 (403) 781-4948 -Original Message- From: Billy Harvey [mailto:[EMAIL PROTECTED]] Sent: Friday, January 18, 2002 12:07 PM To: Darren Gamble Cc: php Subject: RE: [PHP] bug in echo function? On Fri, 2002-01-18 at 13:54, Darren Gamble wrote: Good day, The reason that the first statement doesn't work as intended is due to the order that the operands are processed. The operands in the line: td . ($i*8)+$j . /td are being processed like this: (td . ($i*8))+($j . /td) If you change the line to: td . (($i*8)+$j) . /td then you'll get the desired result. Rule of thumb: Use parenthesis whenever you have a complex operation to ensure the result is what you want. Hmmm - so my assumption that the concatenation operator between the strings gives them a delination equivalent to listing this as three separate echo statements is incorrect, I take it. Shouldn't the echo function process it in this manner from a standpoint of consistency? Thanks for the clarification. Billy -- PHP General Mailing List (http://www.php.net/) To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] To contact the list administrators, e-mail: [EMAIL PROTECTED]
RE: [PHP] bug in echo function?
On Fri, 2002-01-18 at 13:54, Darren Gamble wrote: Good day, The reason that the first statement doesn't work as intended is due to the order that the operands are processed. The operands in the line: td . ($i*8)+$j . /td are being processed like this: (td . ($i*8))+($j . /td) If you change the line to: td . (($i*8)+$j) . /td then you'll get the desired result. Rule of thumb: Use parenthesis whenever you have a complex operation to ensure the result is what you want. Hmmm - so my assumption that the concatenation operator between the strings gives them a delination equivalent to listing this as three separate echo statements is incorrect, I take it. Shouldn't the echo function process it in this manner from a standpoint of consistency? Thanks for the clarification. Billy -- PHP General Mailing List (http://www.php.net/) To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] To contact the list administrators, e-mail: [EMAIL PROTECTED]
