I have to run TCL code written for version 8.5 with the interpreter of version 8.3.

I am having problems with eq. Seems 8.3 doesn't recognize it. A simple code:

% expr { "a" eq "b" }

returns an error message like:

syntax error in expression "a eq b"

I am trying to fix this by adding an interp alias before everything like this:

interp alias {} eq {} ==

but seems it has no effect.

Is there any way to make eq an alias for ==? If no, is the only way to get rid of this error is to replace all eq statements by == statements?