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bug#16411: undo-only bugs
From: |
Stefan Monnier |
Subject: |
bug#16411: undo-only bugs |
Date: |
Sat, 18 Jan 2014 22:18:54 -0500 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/24.3.50 (gnu/linux) |
> Where:
> • delta, beg, end are as documented.
> • undo-redo is a new function that copies undone-element, applies
> undo-delta, then calls primitive-undo on it.
> • undone-element is the undone element of buffer-undo-list.
> • undo-delta is (position . offset) indicating how undo-redo should
> modify a copy of undone-element in order to carry out the redo.
> When executing undo-only:
> • Assume pending-undo-list can be lazily computed
> • Let undo-skip-set be an empty set of undo elements to skip
> • Iterate over pending-undo-list until prefix-arg undos complete:
> • If the element is in undo-skip-set:
> • Remove it from undo-skip-set
> • Continue loop
> • If the element is of the form for a redo element:
> • Insert its undone-element in the undo-skip-set
> • Else undo the element
In which way would this help fixing bug 2 (I thought we had already
understood how to fix bug 2, BTW)?
More problematic: the step "Insert its undone-element in the
undo-skip-set" means that we skip this "redo" element, which means that
all the subsequent elements (until the matching undone-element) may have
incorrect buffer positions.
Luckily, you probably won't bump into any problem because all these
intermediate elements will themselves be redo elements or be in
undo-skip-set. But it's still dangerous and wasteful (why not skip all
these elements in one swoop as we currently do with undo-equiv-table).
Stefan
- bug#16411: undo-only bugs, Barry OReilly, 2014/01/10
- bug#16411: undo-only bugs, Stefan Monnier, 2014/01/10
- bug#16411: undo-only bugs, Barry OReilly, 2014/01/10
- bug#16411: undo-only bugs, Stefan Monnier, 2014/01/10
- bug#16411: undo-only bugs, Barry OReilly, 2014/01/11
- bug#16411: undo-only bugs, Stefan Monnier, 2014/01/13
- bug#16411: undo-only bugs, Stefan Monnier, 2014/01/13
- bug#16411: undo-only bugs, Barry OReilly, 2014/01/14
- bug#16411: undo-only bugs, Barry OReilly, 2014/01/18
- bug#16411: undo-only bugs,
Stefan Monnier <=
- bug#16411: undo-only bugs, Barry OReilly, 2014/01/19