[issue39760] ast.FormattedValue.format_spec unnecessarily wrapped in JoinedStr

[Eric V. Smith]

Eric V. Smith <eric at trueblade.com> added the comment:

I agree that could probably be simplified, if the format_spec is constant (which it need not be).

>>> ast.dump(ast.parse('f"is {x:d}"'))

"Module(body=[Expr(value=JoinedStr(values=[Str(s='is '), FormattedValue(value=Name(id='x', ctx=Load()), conversion=-1, format_spec=JoinedStr(values=[Str(s='d')]))]))])"

But:

ast.dump(ast.parse('f"is {x:{length+1}d}"'))

"Module(body=[Expr(value=JoinedStr(values=[Str(s='is '), FormattedValue(value=Name(id='x', ctx=Load()), conversion=-1, format_spec=JoinedStr(values=[FormattedValue(value=BinOp(left=Name(id='length', ctx=Load()), op=Add(), right=Num(n=1)), conversion=-1, format_spec=None), Str(s='d')]))]))])"

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nosy: +eric.smith

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Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue39760>
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