[swift-evolution] [Proposal] Refining Identifier and Operator Symbology

Martin Waitz tali at admingilde.org
Fri Oct 21 06:38:43 CDT 2016


Am 2016-10-20 17:14, schrieb Jonathan S. Shapiro via swift-evolution:
> If we actually wanted to solve the noun/verb issue, we need to
> acknowledge that being a noun (verb) is orthogonal to being a
> conventional identifier (math symbol identifier).

I really like the idea of separating tokenization of names and
detection of 'normal' identifiers vs. operators.

> Unfortunately every change comes at a cost, and the cost of this one
> is that we would once again have to be thoughtful about white space.

Maybe we can minimize the change and confusion by using several groups 
of characters
which each can form a valid identifier token.

  * one group based on the tokenization of identifiers (as specified in 
this proposal)
  * one group based on ASCII operator symbols (again as specified in the 
  * all other characters stand for themselves and directly name an 

That is: either use letters and numbers to build a name, or use ASCII 
symbols to build a name.
All other characters can also be used, but they don't combine with each 
other and would have
to be descriptive enough to directly name an identifier.
For all the mathematical symbols which were discussed here, this should 
not be a problem.
They already have a meaning of their own and do not have to be combined 
with each other.

This way, no explicit white space would be required between identifiers 
and operators,
assuming that the operators either use ASCII-only operator characters or 
some Unicode
operator symbol.

We could keep easy tokenization and still allow almost all use-cases of 
operators which
were presented here.


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