======Synopsis:======
[[eval]] //<block>//

======Description:======
[[Eval]] treats its arguments as a [[block statement|ircii_syntax]] and
executes it.  Generally the only place you need to use [[eval]] is at the 
input prompt.  Normally the commands you type at the input prompt are treated 
as command statements that already expanded;  If you wish to put $-expandos
in your statement and have them substituted, you would not ordinarily have
any way to do that.  But the [[eval]] command provides for this.

This is the reason why using [[eval]] in a script is so dangerous.  Because
command statements are expanded before the command is executed, it is 
possible for dangerous text to be included in the argument list.  You must
never pass to [[eval]] anything that contains text from an untrusted 
source (ie, from the server)

But for a more concrete example, [[eval]] allows you to indirectly reference
variables, but only if you're careful about it:

	if (1) {
	   @ variable = 'this is some text';
	   @ indirect = '$variable';
	   echo $indirect;
	   eval echo $indirect
	};

The output of these two echos are:

	$variable
	this is some text

Why does this work?  Because ircII expands $'s in the command and then splits
it into a command and an argument:

	eval echo $indirect

expands to:

	eval echo $variable

and the [[eval]] command expands the arguments, and runs them:

	"eval" + "echo $variable"

becomes

	"eval" + "echo this is some text"

and this results in the second line of output.  You have to be very careful
about this, because if you [[eval]] a string that comes from an untrusted
source, someone could take over your client.  Consider this:

	on public * {eval echo $*}

Now consider if someone says "hi there!;exec rm -rf ~"

	"eval echo $*"

becomes

	"eval echo hi there!;exec rm -rf ~"

which becomes

	"eval" + "echo hi there!;exec rm -rf ~"

If this occurs, epic will dutifully remove all your files.  **BE CAREFUL!**
Do not use [[eval]] without a very good reason!

======History:======