Issue 16 in f2py: Strange behevior related to include statement. No Include class yet in nclock_statement.py
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New issue 16 by TakaoKotani: Strange behevior related to include statement.
No Include class yet in nclock_statement.py
http://code.google.com/p/f2py/issues/detail?id=16
Hi pearu,
I looked into r40. It works OK.But two point if you can modify.
1. When I parsed a code, I can not find the include statement.
It seems that there is no class for the include statement.
I think the include statement should make depth one-rank deeper
(as an attribute of the "Include" Class, included file name.
Maybe relative path from the source is good from
the view of protability).
---Now we see strange results; span gives a line number in the included
file.
2.Then I found that the include statement in a fortran code is automatically
classified to a comment. I think this is wrong procedure.
It makes difficult to use fparser as a rewriter.
If you introduce a class for include, then its instance
of included file is just empty, and no content.
So two problems above is systematically solved by adding a "Include" Class
in block_statement.py, I think
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Status: Started
Comment #1 on issue 16 by pearu.peterson: Strange behevior related to
include statement. No Include class yet in nclock_statement.py
http://code.google.com/p/f2py/issues/detail?id=16
Note that INCLUDE line is not a Fortran statement according to Fortran
standard.
And hence there should not be an Include class derived from Statement.
Hmm, it seems that the issue of resolving INCLUDE lines is similar
to the issue of resolving preprocessor directives.
The "Source form" section in Fortran standard gives an idea how to resolve
these
issues for rewriter type of applications. It says that
"""
A Fortran program unit is a sequence of one or more lines, organized as
Fortran
statements, comments, and INCLUDE lines.
"""
For fparser we could extend this definition to
"""
A Fortran program unit is a sequence of one or more lines, organized as
Fortran
statements, comments, and INCLUDE lines, and preprocessor directives.
"""
and let the fparser reader to return three types of instances:
Line - contains a Fortran statement
Comment - contains a comment
Unresolved - contains an unresolved INCLUDE line or an preprocessor
directive.
And there should be an option whether INCLUDE lines should be resolved or
not.
Similarly, there should be an option for applying preprocessor or not.
Btw, the fact that statements in included files start from 1, is expected.
The corresponding Line instances have different reader instance.
f2...@googlecode.com
Comment #2 on issue 16 by TakaoKotani: Strange behevior related to include
http://code.google.com/p/f2py/issues/detail?id=16
I think "include" is a part of fortran standard (a standard extention).
Within my knowledge, I don't know a fortran compilar which do not allow
include
statement. So I think it is reasonable to treat it as a Statement.
(When F77, complex*8 or so are not in fortran regulation, but it was
taken as a standard extension).
----
I don't think it is so meaningful for the fortran reader to classify "input
lines" so
much. Reader should be just a reader. So we have
Comment - contains comment line.
Not affects to any functions of obtained binaries.
Line - Except Comment. It recognizes line continuation, and line division
by ;.
(thus Line is meaningful unit in codes).
IncludedLine - These are Line from included files.
This can be derived from Line class.
FortranFileReader should allow the to specify location of *.inc files.
I think *.inc need not allow include statement in it; but I don't know.
---
When fparser can recognize preprocessor in future, I think a line starting
from '#'
is simply classified to a Line. Then parser identify it as a preprocessor
directive.
Or maybe reader can recognize it as PreprocesserDirective or so.
---
So, maybe, I guess that the introduction Unresolved class do not simplify
fparser and
its concept. But, anyway, I have little knowledge on fparser. I have to
respect your
decision.
f2...@googlecode.com
Comment #3 on issue 16 by pearu.peterson: Strange behevior related to
http://code.google.com/p/f2py/issues/detail?id=16
See at the end of
http://www.f2py.com/home/references
where you will find Fortran language standards.
Take, for example, Fortran 2003 where you'll find that
INCLUDE line is indeed part of the Fortran standard
but it is not a Fortran statement.
F77 complex*8 has another story.
FortranFileReader has include_dirs kw argument that
can be used to specify the location of included files.
In fparser, Line is interpreted as a line that
contains single and complete Fortran statement, that is,
line continuations are resolved by the reader.
It is already a difficult task and I don't want the
parser deal with it.
Note that initially the main application of fparser
was not to rewrite Fortran codes but to get useful
information from it for wrapper generation. Later it
turned out that fparser could be used for rewriting
Fortran codes as well.
Using IncludeLine is a good idea. For preprocessor lines
we could have PPLine or similar.
I don't think we would need any more different classes.
These four should cover all cases.
f2...@googlecode.com
Comment #4 on issue 16 by TakaoKotani: Strange behevior related to include
http://code.google.com/p/f2py/issues/detail?id=16
> Using IncludeLine is a good idea. For preprocessor lines
> we could have PPLine or similar.
> I don't think we would need any more different classes.
> These four should cover all cases.
I also think so.
In anyway, current revision r41 change "include foo" to "! include foo" as
Comment.
I think this is not good (I can not distingush whether ! exist from
the begining or just the FortranFileReader add it). I think
it is reasonable to leave it as a Line. And parset just do "nothing" for
Include class.