[erlang-questions] Did Erlang's grammar change in R16A?

Richard Carlsson <>
Thu Feb 14 20:08:06 CET 2013


On 2013-02-14 20:03, Evan Miller wrote:
> As I understood it, dots are legal in unquoted atom names. This
> appears not to be the case in R16A. Is this intentional?
>
>
> Erlang R15B03 (erts-5.9.3.1) [source] [smp:8:8] [async-threads:0]
> [hipe] [kernel-poll:false]
>
> Eshell V5.9.3.1  (abort with ^G)
> 1> a.b.
> 'a.b'
> 2>
>
>
> Erlang R16A (erts-5.10) [source] [smp:8:8] [async-threads:10] [hipe]
> [kernel-poll:false]
>
> Eshell V5.10  (abort with ^G)
> 1> a.b.
> * 1: syntax error before: '.'
> 1>
>
>
> Kai Janson noticed this because the "mongodb" package fails to compile
> under R16A due to a syntax error on an atom with a dot in it.
>
> https://github.com/mongodb/mongodb-erlang
>
> I couldn't find any mention of changing the grammar in the README. Is
> this a bug?

The automatic concatenation of atoms separated by dots was originally 
introduced with the experimental "packages" system, and was probably 
lost again when this feature was dropped from the codebase.

     /Richard




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