What is "Eval"? The eval, is a calculation on variables(int, str,...).
For example, 2 + 2 is a eval. 400*(20-10) is a eval. This is not only math eval. For example, "hello " + "world" is a eval. also this can contain variables, "Hello " + $name is a eval. Also this can contain function call, say_hello($name) + '.' is a eval.
But how this eval is handled by Loza Core executor?
You can see parse_eval function in prevoius part in lexer.
This function gets a Loza eval string and Converts it to python code. Then, that python code will be ran by executor.
For example, "Hello " + $name will be converted to "Hello " + self.get_var('name'). The $name was replaced with self.get_var('name').
Also this handles functions and classes. for example some_func($name) will be converted to self.functions["some_func"](self.get_var('name')).
The output Python code will be ran using Python's eval function Inside program.Program object, means that the self points to program object(src/core/program.py).
There is a method named eval in program.Program object, this method gets code and converts that to python code using lexer, then, runs that as a python code.
There is a important method named get_var in program object. This method gets name of a variable and returns value of that, but if variable does not exists, raises variable error.
You will learn more about program.Program object features.