3.30. Excuting arbitrary commands in SpecTcl (new in 5.5)

This is intended to support access to user defined SpecTcl commands. The REST interface, however arbitrary commands and scripts can be run in the interpreter using this interface:

This runs the Tcl script that is the value of the query parameter command at the global level of the

The result of the command is returned in the detail of the returned object. If the command raised an error, the status attribute of the returned object will be ERROR and the detail field of the returned data will have the error message raised as its value.

SpecTcl interpreter. tcl-command need not be a simple script. For example, if tcl-command's value is:

 {
    set result [list]
    foreach s [parameter -list] {
        lappend result [lindex $s 0]
    }
    set result
}

                

The detail field of a request with this as the command value will contain a Tcl list (not JSON array) containing the names of all parameters.

A very important point is that the server does no interpretation of the script's returned values. This is fine for Tcl clients but may be difficult to deal with properly for clients in other languages or in programs that cannot embed a Tcl interpreter to parse the results.