how to prevent history expansion

[Sean H. <SHe...@ic...>]

I need to know if there is a way to stop ! expansion. I would have thought that ! expansion would only happen if it's the first char on the command line. I'm trying to use ! as a boolean not. It doesn't seem to work inside the ::tclreadline::Loop

more .tclshrc 
if {$tcl_interactive} {
package require tclreadline 
::tclreadline::Loop
}

tclsh
tclsh8.4 [~]puts [expr {(!([string compare "yes" "yes"])) ? "yes" : "no"}]
>

If I run the same command outside of the ::Loop it works as I'd expect it to:
tclsh
% puts [expr {(!([string compare "yes" "yes"])) ? "yes" : "no"}]
yes
%