Repository navigation
Column offsets in nested f-string expressions are wrong #114
Description
Parsing the following:
expr = """
a = 10
f'{a * f"-{x()}-"}'"""
produces the following AST (not complete):
...
op=Mult(),
right=JoinedStr(
values=[
Constant(
value="-",
lineno=1,
col_offset=5,
end_lineno=1,
end_col_offset=15,
),
FormattedValue(
value=Call(
func=Name(
id="x",
ctx=Load(),
lineno=1,
col_offset=9,
end_lineno=1,
end_col_offset=10,
),
args=[],
keywords=[],
lineno=1,
col_offset=9,
end_lineno=1,
end_col_offset=12,
),
conversion=-1,
lineno=1,
col_offset=5,
end_lineno=1,
end_col_offset=15,
),
Constant(
value="-",
lineno=1,
col_offset=5,
end_lineno=1,
end_col_offset=15,
),
],
lineno=3,
col_offset=7,
end_lineno=3,
end_col_offset=17,
...
Activity
lysnikolaou commentedon Apr 21, 2020
@pablogsal @gvanrossum Is there a way to fix this in a way that doesn't require too much effort? I can't think of something.
[-]Line numbers in nested f-string expressions are wrong[/-][+]Column offsets in nested f-string expressions are wrong[/+]lysnikolaou commentedon Apr 28, 2020
Line numbers were fixed by pre-feeding starting line and column numbers to the parser in 991a634. There is still a bug with the column offsets, because the node shifting of the nested expression is executed before that of the outer one.
pablogsal commentedon Apr 28, 2020
Would a single node-shift of the whole f-string tree work? Or we do require two (ordered) shifts?
lysnikolaou commentedon Apr 28, 2020
That might work, yeah! I'll work on it in a bit.
bpo-40334: Fix shifting of nested fstrings