| ActiveTcl User Guide |

### Tcl >> Tcl Built-In Commands >> Control Constructs

Control Constructs
    after - Execute a command after a time delay
    break - Abort looping command
    catch - Evaluate script and trap exceptional returns
    continue - Skip to the next iteration of a loop
    error - Generate an error
    eval - Evaluate a Tcl script
    for - 'For' loop
    foreach - Iterate over all elements in one or more lists
    if - Execute scripts conditionally
    return - Return from a procedure, or set return code of a script
    switch - Evaluate one of several scripts, depending on a given value
    update - Process pending events and idle callbacks
    uplevel - Execute a script in a different stack frame
    vwait - Process events until a variable is written
    while - Execute script repeatedly as long as a condition is met

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