TCL Function
Last update : 08/02/2006

ScilabEval - tcl instruction : Evaluate a string with scilab interpreter

### Calling Sequence

  `ScilabEval instruction`
  `ScilabEval instruction "seq"`
  `ScilabEval instruction "sync"`
  `ScilabEval instruction "sync" "seq"`
  `ScilabEval "flush"`

### Parameters

- `instruction`: tcl string character contains a Scilab instruction to evaluate with the current Scilab interpreter.

### Description

This function must be called in a tcl/tk script executed from Scilab. It allows to associate Scilab actions to tcl/tk widgets (graphic objects) or to use Scilab to perform some computations within a tcl script.

  - ScilabEval instruction

    If the `ScilabEval instruction` syntax is used, the `instruction` is first stored in a FIFO queue, `ScilabEval` returns immediately. Scilab executes the queued `instructions` when possible (it should be at the prompt but also at the end of each instructions of the currently running function) in the order they were submitted. This syntax can be used to associate Scilab actions to tcl/tk widgets but not into a tcl script executed by `TCL_EvalFile` or `TCL_EvalStr` because in this situation the Scilab interpreter is blocked up to the end of the script. Note that with the `ScilabEval instruction` syntax, if there are many `ScilabEval` commands stored in the queue the execution of the second one can be started in the middle of the execution of the first one (in particular if the first one contains more than a simple expression).

    If the `"seq"` option is added, the associated instruction evaluation should be finished (or paused) before the next queued instruction evaluation can be started. The next callback stored in the command queue will only be taken into account when the current one will be finished or paused.

  - ScilabEval instruction "sync"

    If the `ScilabEval instruction "sync"` syntax is used, the instruction is executed immediately (not queued) and the `ScilabEval`returns when the `instruction` evaluation is finished. The scilab `instruction` evaluation may be interrupted by new or queued commands.

    If the `"seq"` option is added, the associated instruction evaluation should be finished (or paused) before any queued instruction evaluation can be started. The scilab `instruction` evaluation may not be interrupted by new or queued commands (except if it is paused).

  - ScilabEval "flush"

    If the `ScilabEval "flush"` syntax is used, all the previously queued `instructions` are executed immediately and the ScilabEval returns when the execution is finished. Each `instruction` is executed with the option used at the time of queuing up (i.e. `seq` or no option).

The evaluation context of all these cases is the current Scilab context when the`instruction` evaluation starts.

### Examples

    //Callbacks and "seq" option usage

    //create tcl instructions
    tcl_script=['toplevel .w1'
    'button .w1.b -text ""Click here to execute without seq option""  -command WithoutSeq'
    'button .w1.b1 -text ""Click here to execute with seq option""  -command  WithSeq'
    'pack .w1.b .w1.b1'
    'proc  WithoutSeq {} { ';
    '  ScilabEval ""cont=%f;;cont=%t;"" '
    '  ScilabEval ""if cont then disp(''ok''),else disp(''wrong'');end;cont=%f;"" '
    '}'
    'proc WithSeq {} { ';
    '  ScilabEval ""cont=%f;;cont=%t;""  ""seq""'
    '  ScilabEval ""if cont then disp(''ok''),else disp(''wrong'');end;cont=%f;"" '
    '}'];
    mputl(tcl_script,TMPDIR+'/test.tcl') //write them to a file
    // Execute the tcl script
    cont=%f;
    TCL_EvalFile(TMPDIR+'/test.tcl');;

    //scripts and "sync" option usage

    //----------------without "sync"----------------
    tcl_script=['  set t ""0""'
        '  while {$t != ""10""} {'
        '     ScilabEval ""a=$t;mprintf(''%d '',a);""'
        '     incr t'
        '  }'];

    mputl(tcl_script,TMPDIR+'/test.tcl') //write them to a file
    // Execute the tcl script
    TCL_EvalFile(TMPDIR+'/test.tcl');mprintf('TCL_EvalFile finished\n');
    // The ScilabEval are executed  after the and of TCL_EvalFile

    //----------------with "sync"----------------
    tcl_script=['  set t ""0""'
        '  while {$t != ""10""} {'
        '     ScilabEval ""a=$t;mprintf(''%d '',a);"" ""sync""'
        '     incr t'
        '  }'];

    mputl(tcl_script,TMPDIR+'/test.tcl') //write them to a file
    // Execute the tcl script
    TCL_EvalFile(TMPDIR+'/test.tcl');mprintf('TCL_EvalFile finished\n');
    // The ScilabEval are executed  synchronously with TCL_EvalFile

### See Also

`TCL_EvalFile`, `TCL_EvalStr`, `TCL_GetVar`, `TCL_SetVar`,

### Author

Bertrand Guiheneuf