I'm not sure what that line of code is doing. You'd have to trace
through to see exactly what sequence of tokens can lead to it being
run.
However, I will say in general that it would make sense to me to split
out implicit multiplication via a space and implicit multiplication
via parentheses. It's only the latter that is ambiguous with function
application. Unfortunately, this is a general ambiguity that is
inherent in mathematical notation. Does x(y + z) mean x is a function
of y + z or does it mean xy + xz? There's no way to know from the
notation alone.
Aaron Meurer
On Mon, Nov 22, 2021 at 11:30 AM Paul Royik <distantjob...@gmail.com> wrote:
>
> I've found the following piece of code in _implicit_multiplication
>
> elif (isinstance(tok, AppliedFunction) and
> nextTok[0] == OP and nextTok[1] == '('):
> # Applied function followed by an open parenthesis
> if tok.function[1] == "Function":
> result[-1].function = (result[-1].function[0], 'Symbol')
> result.append((OP, '*'))
>
> Is there any reason to substitute a Function with a Symbol?
>
> On Monday, November 22, 2021 at 9:00:13 AM UTC+2 Paul Royik wrote:
>>
>> I want to parse something like `f(x) - 2 sin 3x`.
>>
>> If I use `parse_expr` without `implicit_multiplication_application`, then
>> `f(x)` is parsed correctly, but not `2 sin 3x`.
>>
>> If I include `implicit_multiplication_application`, then `f(x)` is parsed as
>> `fx`.
>>
>> Is this a bug?
>
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