The python command is a Tcl command ensemble that has two subcommands.
Accepts a filename and executes the python script in that file.
Accepts a python script and executes that script. Prior to running the script a single variable substitution pass is run over the script. This substitution pass is run regardless of the top level quoting.
Example 2-1. Running a script file
python source myscript.py
This example runs a python script that is stored in myscript.py
Example 2-2. Running an immediate script
python exec { print("Hello world from python") }
This prints the string Hello world from python on stdout. Note that if you are running the TkCon console, the output will not come out there but on the terminal that started SpecTcl. This is because python is not aware of the Tcl redirection of its stdout and stderr file descriptors to that console window.
Example 2-3. Tcl variable substitution
set spectrumName myspectrum
python exec {
s = spectcl.spectrum('$spectrumName')
print(s.name)
print(s.type)
print(s.parameters)
print(s.axes)
}
Creates a python spectrum object that wraps
the spectrum named by the Tcl variable
spectrumName (in this case
myspectrum).
The name, type, parameter list and axis definitions
of the spectrum are printed to stdout.
Note we needed to quote the variable substitution so that the resulting parameter would be a properly quoted literal string from python's point of view.