Tcl and the Tk Toolkit, Second Edition

8. Control Flow

This chapter describes the Tcl commands for controlling the flow of execution in a script. Tcl’s control flow commands are similar to the control flow statements in the C programming language and the Unix shell csh, including if, while, for, foreach, switch, and eval.

8.1 Commands Presented in This Chapter

You can use the following commands to control the flow of execution in a Tcl script:

• break

Terminates the innermost nested looping command.

• continue

Terminates the current iteration of the innermost looping command and goes on to the next iteration of that command.

• eval arg ?arg arg ...?

Concatenates all of the args with separator spaces, then evaluates the result as a Tcl script and returns its result.

• for init test ...