syntax difference

[Ed Kellett]

On 2018-06-18 13:18, Chris Angelico wrote:
> 1) Parse the code, keeping all the non-essential parts as well as the
> essential parts.
> 2) Find the comments, or find the annotations
> 3) If comments, figure out if they're the ones you want to remove.
> 4) Reconstruct the file without the bits you want to remember.
> 
> Step 3 is removed if you're using syntactic annotations. Otherwise,
> they're identical.

It's likely that Python comments are much easier to remove than
arbitrary bits of Python syntax--you need to know the answer to "am I in
a string literal?", which is a lexical analysis problem you could hack
together a solution for over the course of about one coffee, as opposed
to "where exactly am I in the Python parse tree?", which is... harder.
The information you need to keep track of and later reconstruct is
substantially simpler, too.

I don't think "they're hard to mechanically remove" is a particularly
good argument against type hints, but considered on its own it probably
is true.

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