nntp.charter.net wrote:
I want to write a trace procedure and call it with variable names, and I am having trouble with the syntax. My goal is to have a procedure that will echo lines such as:

Trace: $myvar="the contents of $myvar

My attempt that didn't work is to write a function:

function my_trace($m){
   echo ("\n<br>TRACE: $m = ");
   eval("\$t=\"$m\";");
   echo($t."<br>\n");
 }

and call it with statements like:

my_trace("\$my_var");
my_trace("\$_ENV[\"COMPUTERNAME\"]");

What am I doing wrong, and how should this be done? Also, should I post to a different group?

Thanks,
Gil Grodsky
[EMAIL PROTECTED]


Try this script, it works for me:

$my_var = 'Hello world!';

function my_trace($m){                   // pay attention to the use of single 
vs double quotes throughout
$q = substr($m, 1);                   // chop off the leading '$' in the 
variable name
@eval("global \${$q};");              // need to use global to get value of 
local variables into this function
                                    // also need @ to supress warning caused by 
brackets in superglobal variables
eval("\$t = \${$q};");                // assign value of orginal $m to $t
echo ("<br />TRACE: $m = $t<br />"); // output
my_trace('$my_var');                     // note the use of single quotes here
my_trace('$_ENV["COMPUTERNAME"]');       // note where the single quotes are 
used here

Hope it helps,
Bob

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