Ok I have read a few times of the tutorial of Smacc in here http://www.refactoryworkers.com/SmaCC/ASTs.html and I am also following the help tool documentation inside pharo for SmaCC and I have to say I am very confused. Please bare with me because I am extremely noob when it comes to parsing, this is my first effort. Now the way I understand it so far, is that SmaCC uses a syntax similar to regex expressions to define parsers and scanners. Scanners evaluate a string to see that it contains a valid form and parser divide to parts named as "tokens" and help in the creating of ASTs which are basically hierarchy tree containing the syntax elements of a language. Now in order to make SmaCC work I need to use the SmaCC tool that comes with pharo . The smacc tool takes two inputs a scanner and a parser class. Does that mean I need to create that parser and scanner class ? I thought since I define the syntax that those things would be generated by the tool. What I need to define exactly ? Why when I select the PythonScanner2 and PythonParser2 and click then Compile LR it gives a MNU receiver of method is nil ? I am using latest Pharo 4 image. My goal is to parse python types to similar pharo objects. I get those python types as strings and my main focus in lists, dictionaries and tuples . The tricky part is that one can contain the other inside in every imagined way. The way I understand it I will need something called "transformations" to convert those python types to OrderedCollections, Arrays etc and anything would make more sense for a pharo coder. Additionally what is the meaning of the vertibal bar ? --> | eg. | Number Are there any other tutorials that can help a beginner like me to understand these concepts ? I am not looking for someone to give me the solution to the plate, I would love to learn and understand parsing because I am very interested into making Pharo easy to mix with Python code and allow Pharo to use Python libraries without the user having to learn or code Python :) As you may imagine this is a crucial ingredient for my project Ephestos which tries to use Pharo to script Blender by either replacing or cooperating with blender python. So learning a good way to parse pharo code to python code and vice versa is extremely important for me.