Re: Re: How to print variable name and contents

On Jun 17, 2005, at 9:18 AM, Bob Winter wrote:

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 ggrodsky@charter.net

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 -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php

Dunno if anyone's mentioned it yet, but have you had a look at debug_backtrace()? http://www.php.net/manual/en/function.debug-backtrace.php I use it a lot during development and you skip the eval() call. You should be able to write a simple function to pull the info out that you want, but I usually just do a print_r() on it and manually look through the output. Edward Vermillion evermillion@doggydoo.net