Practical Programming in Tcl & Tk, Third Edition

Creating Interpreters

Here is a simple example that creates an interpreter, evaluates a couple of commands in it, and then deletes the interpreter:

Example 19-1 Creating and deleting an interpreter.

interp create foo => foo interp eval foo {set a 5} => 5 set sum [interp eval foo {expr $a + $a}] => 10 interp delete foo

In Example 19-1 the interpreter is named foo. Two commands are evaluated in the foo interpreter:

set a 5
expr $a + $a

Note that curly braces are used to protect the commands from any interpretation by the main interpreter. The variable a is defined in the foo interpreter and does not conflict with variables in the main interpreter. The set of variables and procedures in each interpreter is completely independent.

The Interpreter ...