[erlang-questions] Accessing a single value from MAPS

Richard Carlsson <>
Thu Oct 8 20:57:08 CEST 2015


On Thu, Oct 8, 2015 at 4:41 PM, Fred Hebert <> wrote:

> On 10/08, Richard Carlsson wrote:
>
>> Not quite. The end-of-form (or 'dot') token requires that the period
>> character is followed by whitespace, a comment, or end-of-file. Otherwise
>> it's a '.' token, as is already in use in expressions like
>> Record#recordname.fieldname.
>>
>
> Am I right in assuming mnesmosyne was like records currently are and
> packages were -- mostly using atoms as fields?
>
> There's an interesting distinction for maps in that any data structure·
> whatsoever might be a key, even tuples:
>

Yes, only atoms were allowed as field selectors back then. I think a
general operator <Expr> '.' <Expr> would be possible, but it might lead to
horrible code, as you point out.
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