Chapter 6 Remote Tcl Interface

This chapter describes the remote Tcl interface, which allows a separate external Tcl program to interact with ECLⁱPS^e in much the same fashion as the embedding Tcl interface (see chapter 5). Like the embedding interface, Tcl and ECLⁱPS^e code communicates by sending and receiving streams of bytes via I/O queues (the ec_rpc mechanism is implemented on top of these queues). The interface can thus be used in similar fashion to the embedding interface, e.g. for the development of graphical user interfaces to an ECLiPSe application, with the difference that the ECLⁱPS^e program is a separate program and not embedded into the Tcl program.

The main features of the interface are:

The connection between the Tcl and ECLⁱPS^e processes are established via sockets using TCP network protocol. Thus the Tcl process can be run on a different machine and platform from the ECLⁱPS^e process.
The Tcl process can be attached to any running ECLⁱPS^e process, including an ECLⁱPS^e embedded into another host language.
More than one Tcl (or other remote) process can be attached to a single ECLⁱPS^e via the remote interface.
For the programmer, the embedding and remote interfaces are largely similar, and once the connection is established in the remote interface, the same code on the ECLⁱPS^e and Tcl sides can be used for both interfaces.

The remote interface thus offers more flexibility than an embedding interface in how the Tcl code can be connected to an ECLⁱPS^e program. However, as the Tcl and ECLⁱPS^e processes are not as tightly coupled as in an embedded interface, the speed of communications between the Tcl and ECLⁱPS^e processes is likely to be slower.