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bug#6878: bool-vectors of length 0 signal error when aref/aset the 0th e
From: |
Stefan Monnier |
Subject: |
bug#6878: bool-vectors of length 0 signal error when aref/aset the 0th element |
Date: |
Thu, 19 Aug 2010 17:51:51 +0200 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/24.0.50 (gnu/linux) |
>>> ,---- (info "(elisp)Bool-Vector Type")
>>> | "A "bool-vector" is a one-dimensional array of elements that must be `t'
>>> | or `nil'."
>> All elements of (make-bool-vector 0 t) are either t or nil.
> Prove it!
Easy! formally, he said:
∀ n ≥ 0 ∧ n < 0. (aref (make-bool-vector 0 t) n) ∈ { nil, t }
And since there is no such `n', this is trivially true.
More specifically, "n ≥ 0 ∧ n < 0" is a falsehood, and from false you
can conclude anything you wish. Among other things you can just
a trivially prove:
∀ n ≥ 0 ∧ n < 0. the sky is green
-- Stefan
- bug#6878: bool-vectors of length 0 signal error when aref/aset the 0th element, MON KEY, 2010/08/18
- bug#6878: bool-vectors of length 0 signal error when aref/aset the 0th element, Stefan Monnier, 2010/08/18
- bug#6878: bool-vectors of length 0 signal error when aref/aset the 0th element, MON KEY, 2010/08/18
- bug#6878: bool-vectors of length 0 signal error when aref/aset the 0th element, Andreas Schwab, 2010/08/19
- bug#6878: bool-vectors of length 0 signal error when aref/aset the 0th element, MON KEY, 2010/08/19
- bug#6878: bool-vectors of length 0 signal error when aref/aset the 0th element,
Stefan Monnier <=
- bug#6878: bool-vectors of length 0 signal error when aref/aset the 0th element, MON KEY, 2010/08/19
- bug#6878: bool-vectors of length 0 signal error when aref/aset the 0th element, Stefan Monnier, 2010/08/19
- bug#6878: bool-vectors of length 0 signal error when aref/aset the 0th element, Andreas Schwab, 2010/08/19
- bug#6878: bool-vectors of length 0 signal error when aref/aset the 0th element, Chong Yidong, 2010/08/19
- bug#6878: bool-vectors of length 0 signal error when aref/aset the 0th element, MON KEY, 2010/08/19
- bug#6878: bool-vectors of length 0 signal error when aref/aset the 0th element, Juanma Barranquero, 2010/08/19
- bug#6878: bool-vectors of length 0 signal error when aref/aset the 0th element, Chong Yidong, 2010/08/19
- bug#6878: bool-vectors of length 0 signal error when aref/aset the 0th element, MON KEY, 2010/08/19
- bug#6878: bool-vectors of length 0 signal error when aref/aset the 0th element, Juanma Barranquero, 2010/08/19
- bug#6878: bool-vectors of length 0 signal error when aref/aset the 0th element, MON KEY, 2010/08/20