feature_request(formatting): wrap long strings

[Kristinita]

1. Summary

It would be nice, if Black will wrap long strings.

2. Example

I have SashaLongStrings.py file:

print("She's the one for me, She's my ecstasy, She's the one I need. She's one in a million, She's once in a lifetime, She made me discover one of the stars above us.")

Line contains 168 characters.

I run command:

black --line-length 120 SashaLongStrings.py

Result:

print("She's the one for me, She's my ecstasy, She's the one I need. She's one in a million, She's once in a lifetime, "
      "She made me discover one of the stars above us.")

Lines contains ≤ 120 symbols.

3. Details

See more details in my question in Software Recommendations.

Thanks.

[ambv]

This is something we will probably do in the future but it's a trickier request than it looks on the surface.

We would need to handle breaking strings safely in face of escapes, formatting variables (old style %s and {0}, new style f-strings), method calls on the resulting string, and so on.

[davidism]

I know Black doesn't split strings yet, but can we preemptively make a style decision about leading / trailing whitespace when splitting strings?

When wrapping on words, I like to keep the separating whitespace at the beginning of the next line. Visually I think it's easier to recognize that the string is wrapped, and I think it feels like the "binary op at beginning of line" rule.

raise TypeError(
    "Pretend that this"
    " is a long line."
)

Ultimately I don't care what way we decide, I just want to be consistent.

[mlucool]

@ambv is this feature still planned?

[NicolasPA]

A detail to take into account, Black doesn't behave well with wrapped long strings in dictionaries.

1. Unwrapped long string, running black on it won't change anything as said earlier:

long_string = {
    "a": "All kinds of interesting questions which the science knowledge only adds to the excitement, the mystery and the awe of a flower.",
    "b": "azazd",
}

2. Wrapped (using Pycharm suggested intention action):

long_string = {
    "a": "All kinds of interesting questions which the science knowledge only adds to the excitement, the mystery and "
         "the awe of a flower.", 
    "b": "azazd",
}

3. Running black after that wrapping:

long_string = {
    "a": "All kinds of interesting questions which the science knowledge only adds to the excitement, the mystery and "
    "the awe of a flower.",
    "b": "azazd",
}

The problem here is that the wrapped part of the line looks like a new dictionary item at first sight. It would be nice to keep the formatting from point 2.

[KeirSimmons]

Is this still planned?