The fpc TCL unit and demo work better on tcl8.0.5.
The main trick to interfacing tcl script channels (and other tcl types) is procedural-types. (Both fpc and gpc support them.) The types declared in the tcl unit need to conform to the tcl C library structures. So it seems once object pascal is used to build the actual tcl command, a large improvement in the tcl language results.
Sort of like a Pascal TclX.