# TCL_EvalFile

Reads and evaluate a tcl/tk file

## Calling Sequence

    TCL_EvalFile(filename [,interp])

## Arguments

filename

  character string. Contains the name of the file to read and evaluate.

interp

  optional character string parameter. Name of the slave tcl interpreter in which the operation has to be performed. If not provided, it defaults to the main tcl interpreter created by Scilab.

## Description

With this routine, one can read and evaluate the content of a file containing tcl/tk scripts. This allows to create powerful tk interfaces.

The filename might be relative or absolute.

## Advantages and drawbacks of this functionality

This routines allows to use directly tcl/tk scripts. This thus allows, for instance to use Interface Builders such as SpecTcl to design the interface. The interfaces built directly with tcl/tk scripts are much faster than the ones built with the Scilab Graphic Object library provided with tksci (see uicontrol for example). Indeed, those Objects are warpings around tk graphic widgets. Nevertheless, this way of creating graphic user interface should only be used when one aims at addressing directly specific tk/tcl features. There are two main reasons for this. First of all, there is no simple way to manipulate Scilab objects from within a tcl/tk script. Thus, the interface designer has to write two sets of callbacks routines. One to describe the changes occuring in the interface when the user acts on the widgets. The second set of call routines will perform the (pure) Scilab reactions to the user actions.

Here is an example: Suppose you design a scrollbar corresponding to a spline tension value. You want the spline to be displayed in a graphic windows and updated each time the user moves the scrollbar. At the same time, you want the value of this tension parameter to be displayed within the Interface. You will have to write a first tcl/tk (callback) function which will be automatically called by the tk scrollbar ("-command" option). This callback function will update the displayed value of the parameter in the interface and will then call the scilab routine ("ScilabEval" command) to update the graph.

## Remarks on the tcl/tk script style

Because Scilab manages the tcl/tk events, it creates the root window ".", this window should not be destroyed nor directly used by your tcl/tk scripts. You should thus always create your own toplevel windows. Moreover, since this module was written at a time when namespaces didn't exist, some variables defined by scilab tcl/tk scripts could collide your code. Running your scripts in a slave interpreter may help in such a case.

More information about Tcl/Tk: http://www.tcl.tk/doc/

## Examples

    TCL_EvalFile(SCI+"/modules/tclsci/demos/tk/puzzle");

## See Also

- ScilabEval
- TCL_EvalStr
- TCL_GetVar
- TCL_SetVar
- TCL_ExistVar
- TCL_UnsetVar
- TCL_UpVar