php 4.3.4 new warning

today i has installed php 4.3.4 and has noticed new warning

parse error, unexpected T_ENCAPSED_AND_WHITESPACE, expecting T_STRING or T_VARIABLE or T_NUM_STRING

this error i get in my function which sends e-mails in header construction section

$headers .= "From:\"$mail[sendern]\"<$mail[senderm]>\r \n";
$headers .= "Reply-To:\"$mail['sendern']\"<$mail['senderm']>\r \n";

i think that this warning is connected with escapes ?

where can i read something about this warning ?

thanks u....

reading one article one php.net i came to the solution which i can understand,

my header line was
$headers .= "Reply-To:\"$mail['sendern']\"<$mail['senderm']>\r \n"; == parse error

but if this header is
$headers .= "Reply-To:\"$mail[sendern]\"<$mail[senderm]>\r \n";

then all works fine for me....

why in php single quotas in double quotas give to me parse error.....

thank u

maybe this links wiil be usefull for somebody
http://www.php.net/manual/en/tokens.php

if you use an editor with syntax highlighting you will see differences between these two lines of code although they will produce the very same

 $headers .= "Reply-To:\"$mail[sendern]\"<$mail[senderm]>\r \n";
$headers .= 'Reply-To:"'.$mail['sendern'].'"<'.$mail['senderm'].">\r \n";

i mysql prefer the second one cause i see where i make use of variables

just my 2 pence 😃