String Index out of bound

[Lal47]

Hey when i try to run the parser.py file, I get this error.

[Lal47]

I just cloned the repository and tried running the code. Any leads on this?

[hatamiarash7]

What version of Python are you using and have you installed Pandas?

[CherryChelsea18]

Yeah I have pandas installed

[CO18353]

The error is occurring because of the nulls being stored in list "l". In the for loop, the "lhs" is storing null instead of the first non-terminal and so the "productions" dictionary stores every rule on null index.

If you print the "productions" dictionary, you would see that the production rules are incorrectly stored.

So for fixing this error you just remove the nulls before assigning lhs and rhs.
l=[x for x in l if x != ""]
But another issue that would arise is that the rhs does not store each production rule (specified by "|" in the input) separately.
For that we can first split on the basis of "->" and store the lhs and then split the second list on "|" and store in rhs.

I have used the inbuilt split function of python.
For removing the whitespace and the newline using replace function:
line=line.replace(" ", "").replace("\n", "")
Then split the input at "->" using
l=line.split("->")
And lastly split l[1] on "|"
rhs=l[1].split("|")