Error on concatenation of two strings with a backslash

[mbraakhekke]

The following minimal program results in a NoMatchError for line 2:

program simple
    character(len=10) :: foo = '\' // 'b'
end program simple

I believe this is correct Fortran--at least it compiles fine on Intel.

I'm still investigating myself. It's doesn't seem to be a problem with the regex pattern for the concat-op. I think it has something to do with the fact that backslashes in strings get automatically escaped to \\ in Python.

Interestingly, if I take out the line from the program block, i.e. just:

character(len=10) :: foo = '\' // 'b'

it works fine.

[arporter]

Thanks for reporting this @mbraakhekke. Do you get the expected parse tree for the line in isolation? (I ask because you have to be careful as, unless you tell the reader you have free-format code, it will see the first c and match a fixed-format comment.)

[mbraakhekke]

Thanks for reporting this @mbraakhekke. Do you get the expected parse tree for the line in isolation? (I ask because you have to be careful as, unless you tell the reader you have free-format code, it will see the first c and match a fixed-format comment.)

You're right: the line gets interpreted as a comment. How do I tell the reader the file is free-format?

[arporter]

It's slightly non-intuitive. You need to call set_format() on the reader object (https://fparser.readthedocs.io/en/latest/_static/html/classfparser_1_1common_1_1readfortran_1_1FortranReaderBase.html#ad9e18ea6d859fd5459381d4f1437311d) and pass it an appropriate sourceinfo.FortranFormat object:

from fparser.common.sourceinfo import FortranFormat

reader = ...
reader.set_format(FortranFormat(is_free=True, is_strict=False))
...

[mbraakhekke]

OK thanks. Now the parsing also fails with a FortranSyntaxError. I'll keep digging. Possibly, I can submit a PR.