[cfe-users] C++ Scoring Tool
Daniel via cfe-users
cfe-users at lists.llvm.org
Tue Apr 17 00:40:52 PDT 2018
For the senior project in my undergraduate studies, my team and I are
developing a tool that will evaluate the format and code conventions of
a c++ program, outputting a score and displaying useful messages, very
much like pylint for python.
The idea is kind of like clang-format except no alterations to the code
should be made. The tool would be used as a teaching aid and automatic
grader. To handle the beautiful diversity of c++, it shouldn't constrain
the author to any particular style (although it should be able to do
that too). For example: open curly braces on same line as function
declaration compared to having them on a new line. In this case, the
tool could check for consistency only. As long as the entire file has
the same format, you will get a perfect score. If, however, there are 10
places of braces on same line and 9 on newline, there will be a penalty
to the score, larger than if 18 on same line and 1 on newline. The idea
is to enforce consistency without getting in the way of authors
preferred style. This should give professors a robust tool to teach c++.
I was hoping the clang community could help me understand the inner
workings of clang a little bit better. Right now, my hangup is trying to
get format data to work in conjunction with clangs AST. What I'm trying
to do is get back the whitespace, comment, and bracket information that
is loss during AST buildup. Suppose I want to check that all operators
have consistent spacing format, something like "(2 * 2)" verses "(2*2)"
verses "(2* 2)". The AST will be used to get the semantics of that
particular operator so as to not get it confused with the array pointer
operator, but I need to count the operator whitespace prefix and
postfix. The same concept will be applied to statement whitespace
circumfixs. If done right, I should be able to refer to all operators
the same way no matter the complexity of the expression. Something like
"(x - 4) / 3 * (2 +1)" would show an inconsistency in the end part "(2
+1)" because of a missing space.
My first thought was to use the SourceManager locational information to
point back to the source code, then process and identify the whitespace
from there; However, this seems wildly inefficient and inelegant. My
second thought was to somehow get clang to keep the whitespace
information and add it to the AST, but I believe there are inherent
difficulties with that.
My biggest problem is lack of expertise within clangs source code. Does
anybody have any ideas on how I can get clang to give me the information
I need to support the above functionality?
Thanks for any interest. I hope this is an appropriate mailing list to
post my question.
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