{: .no_toc }

{: .no_toc .text-delta }

1. TOC {:toc}

The python command is the basic unit of work of PythonBridge. It allows developers to run arbitrary python code from Pharo. It is composed by a sequence of python statements, a collection of variable bindings, pharo observers callbacks and a transformation block.

The python statements are created in Pharo by using Python3Generator.

Python objects instance variables and methods are accessible in Python by operator .. From Pharo, this operator is defined using => and allow accessing instance variables and invoking methods.

foo asP3GI => #a    "foo.a"

Python functions and methods are called by using callWith: and callWith:with:.

The callWith: method receive as argument a collection of objects which corresponds to the positional arguments of the call.

foo asP3GI callWith: #(1 2 3)    "foo(1,2,3)"

The callWith:with: method receives as first agument a collection of positional arguments and, as second argument, a dictionary of named arguments.

foo asP3GI 
    callWith: #(1 2 3) 
    with: { 
        #nameArg1 -> 'bar'.
        #nameArg2 -> 5 } asDictionary

"foo(1, 2, 3, nameArg1='bar', nameArg2=5)"

Assignments in python allow you to store objects in globals, temporary variables and instance variables. Python3Generator uses the message <- to assign the value at the right of the message to the receiver.

Assigning the temporary variable w with the array [1,2,3].

foo asP3GI <- #(1 2 3)    "foo = [1,2,3]"

Assigning instance variable a from object in variable foo with the string 'bar'.

(foo asP3GI => #a) <- 'bar'    "foo.a = 'bar'"

Each PythonBridge extension defines its own CommandFactory as a global object. In the case of PythonBridge it's called PBCF and in KerasBridge is called KCF.