Re: Why is Elisp's defvar weird? And is eval_sub broken?

[Daniel Colascione <dancol@dancol.org>]

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On 02/14/2015 06:36 AM, Stefan Monnier wrote:
>> A declaration of free dynamic variables for a function could tell the
>> byte compiler that those free variables aren't typos, since
>> otherwise the byte compiler would expect either the symbol to be
>> declared special or a lexical variable by that name to be in scope.
> 
> There is such a declaration already.  It's called (defvar <foo>).  Tada!
> 
>>> Normally, such conflicts should never happen
>>> because all special vars should be named with a "package prefix", but
>>> sadly, reality is different, so it was indispensable to make this
>>> effect local, to allow lexical-binding code to work reliably.
>> By using llet, the byte compiler will catch such conflicts, and your code
>> (interpreted or compiled) that uses it will work reliably despite the
>> conflicts. This means defvar's weird behavior is no longer needed.
> 
> It's not weird once you understand that it's a compiler directive which
> is absent from the .elc file.

How are users supposed to understand that when it's completely absent
from the documentation?


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