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* Re: [Emacs-diffs] master 9c4e309: Check that variable lists are actually lists
       [not found] ` <20170119161943.49263220159@vcs.savannah.gnu.org>
@ 2017-01-19 16:40   ` Stefan Monnier
  0 siblings, 0 replies; only message in thread
From: Stefan Monnier @ 2017-01-19 16:40 UTC (permalink / raw)
  To: emacs-devel; +Cc: Philipp Stephani

>     'let' and 'let*' document that their first argument has to be a list,
>     but don't check for that; instead, they allow (and silently ignore)
>     other types.  Introduce an explicit type check.

Notice that this may end up breaking currently working code :-(

The way we've generally handled such issues is basically that if the
programmer wants sanity checks, he should byte-compile his code.
This has two corollaries:
- We should make sure that the *byte-compiler* does warn about
  ill-formed code (we currently don't do a great job of that).
- The interpreter can do whatever it wants with ill-formed code and
  doesn't need to go out of its way to detect it.


        Stefan



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2017-01-19 16:40   ` [Emacs-diffs] master 9c4e309: Check that variable lists are actually lists Stefan Monnier

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