Sly parser, how are recursively defined types implemented?

Question

I am new to compiler techniques and started to translate the code below to Matlab.

https://github.com/jol-jol/pymatlabparser/blob/master/pymatlabparser/matlab_parser.py

The tokenizer is done, I have started a simple shift/reduce parser. But no rule seems to yield 'expr' without requiring it in its pattern.

Where does this magic happen, by built-in Python functions and types? An idea how to implement it in Matlab?

Answer 1

Thanks sepp2k.

In

@_('NAME', 'NUMBER', 'STRING')                  # e.g. x, 56, 3e-2, "example"
def expr(self, p):
    return (p[0],)      # creates a tuple for the token to avoid strings getting concatenated later on

I was missing the def expr part. So expr is not created as a token type, but as a function.