I found this code very useful. I've been spelunking in CPython and mostly I understand it, and can find my way around.
But ceval.c is another beast entirely, being full of macros and gotos, not to mention being 5000 lines long.
The interpreter loop starts here: https://github.com/python/cpython/blob/master/Python/ceval.c...
So I appreciate seeing the algorithm laid out in Python. In particular it clarifies that there are three separate stacks:
1. call stack
2. block stack for try/except, loops, etc.
3. value stack for evaluating expressions
It also clarifies how generators work, which IMO is very difficult to follow from the C source (i.e. without a design doc to go along).
I wrote about some of my recent work here: https://www.reddit.com/r/oilshell/comments/8b0n6z/opyreadmem...
BTW I have shell scripts running under triple interpretation: CPython, byterun, and OSH itself :) This is just an experiment toward writing my own VM, not for the final product. The release binary doesn't use byterun at all.
EDIT: There is also a companion bytecode compiler that I mention here: http://www.oilshell.org/blog/2018/03/27.html (but I'm not using it, I'm using the one that used to be in the Python 2 stdlib, which is entirely separate from the one used by the interpreter itself.)
But ceval.c is another beast entirely, being full of macros and gotos, not to mention being 5000 lines long.
The interpreter loop starts here: https://github.com/python/cpython/blob/master/Python/ceval.c...
So I appreciate seeing the algorithm laid out in Python. In particular it clarifies that there are three separate stacks:
1. call stack
2. block stack for try/except, loops, etc.
3. value stack for evaluating expressions
It also clarifies how generators work, which IMO is very difficult to follow from the C source (i.e. without a design doc to go along).
I wrote about some of my recent work here: https://www.reddit.com/r/oilshell/comments/8b0n6z/opyreadmem...
BTW I have shell scripts running under triple interpretation: CPython, byterun, and OSH itself :) This is just an experiment toward writing my own VM, not for the final product. The release binary doesn't use byterun at all.
EDIT: There is also a companion bytecode compiler that I mention here: http://www.oilshell.org/blog/2018/03/27.html (but I'm not using it, I'm using the one that used to be in the Python 2 stdlib, which is entirely separate from the one used by the interpreter itself.)