At the very beginning of do_replace(), nothing has been changed
or initialized yet, so there is nothing to refresh or clean up.

This make tiny nano slightly less tiny, but makes the code more readable.

It does not update anything -- it just picks a new point from
where to start displaying the buffer.  All actual updating of
the screen is done by edit_refresh() and edit_redraw() and such.

This avoids https://savannah.gnu.org/bugs/?49298.

And also case-sensitive searches, backward searches, and searching again.

Mentioning "GNU nano" instead of "This program" and referring to the
website instead of to a postal address.

This fixes https://savannah.gnu.org/bugs/?48635.

The negatives are taken to mean: from the end of the file,
and: from the end of the line.

This fulfills https://savannah.gnu.org/bugs/?48248.

This fixes https://savannah.gnu.org/bugs/?48282.

Don't make it the responsibility of the executed functions to restore
the list of shortcuts of the edit window.  Just detect whether another
menu was displayed, and if so, redisplay the main menu.

This reverts commit df8c3deb from six years ago, which prevented a crash
on the Armel/Maemo platforms but causes nano to lose history items.

The strncmp() function on those platforms treats size_t numbers with
the high bit set as if they were zero.  To avoid that, use a number
that cannot be seen as negative, as suggested by <alpha@qzx.com>.

This fixes https://savannah.gnu.org/bugs/?48048

.
Tested-by: Tito Ragusa <farmatito@tiscali.it>
Signed-off-by: Benno Schulenberg <bensberg@justemail.net>

When opening a file that was edited before, and the remembered position
is near the end of the file, then don't center the target line but show
the last line of the file on the bottom line of the screen, thus showing
as much of the file content as possible.

This addresses https://savannah.gnu.org/bugs/?46243.

If during startup there are multiple error messages, currently only the
last one remains and can be read.  To improve on that, introduce a short
pause between error messages -- even if it's not enough to read them all,
at least the user will be aware that there are multiple ones.

This also causes a few error messages to beep that currently don't beep,
such as when a file is unwritable.

This fixes https://savannah.gnu.org/bugs/?47933.

An interactive 'gotolinecolumn' has already refreshed the screen.

When during searching we look at the keyboard, then don't look at
just the first keystroke, but check if there are more, and if so,
check each one until we find a Cancel -- or until all keystrokes
have been consumed and we can continue.

This fixes the first half of https://savannah.gnu.org/bugs/?47438.

Cancelling a search should restore waiting mode for the keyboard,
just like at the other exit points of the search routine.

And when the input routine has read in multiple keystrokes, it
should not blindly switch back to waiting mode, but only when
that mode was on before.

This fixes the second half of https://savannah.gnu.org/bugs/?47438.

Partitioning the file makes the undo system lose track, so that undoing
things has a good chance of losing data.  Instead, just make sure that
the region is marked "backwards", with current at the top and the mark
at the bottom, and then let the replace loop take care of not going
outside of the marked region.

This also has the effect that if the marked region fits entirely on the
screen, or all the misspellings are onscreen, then the screen will not
be scrolled at all.  Which makes for a smooth experience.

This fixes https://savannah.gnu.org/bugs/?47836,
and fixes https://savannah.gnu.org/bugs/?45573.

Since nano-2.4.1, reading in or pasting a large piece of text would put
the cursor on the bottom line, leaving only one line of the non-read or
non-pasted text visible.  This is different from the centering behavior
of Pico, and somewhat disorienting, as you can't see "where you are" any
more in relation to the file as it was.

So now center the cursor whenever the read or pasted text is larger than
the screen, but don't center it when the text fits entirely on the screen.
(The latter avoids the effect of the screen jumping unnecessarily when
inserting just a few lines while the cursor is near the bottom.)

To achieve this behavior: default to focusing, and temporarily set it to
FALSE when the focusing effect is unwanted.

This fixes https://savannah.gnu.org/bugs/?47841.

When verifying that a match is a separate word (during spell checking),
instead of first copying out the word, then passing the word, and then
measuring its length, just pass its length straigtaway.

When we're spell checking, we don't need a special mechanism to detect
we have come full circle: reaching the end-of-buffer means we're done.
So don't bother to reset came_full_circle when we're spell checking
(when begin == NULL) but simply ignore its value.

The internal spell checker starts searching/replacing always at the top
of the buffer, so reaching the end of the buffer means we're done with
the current search/replace.  This prevents the "Search Wrapped" message
from flashing over the statusbar at the end of a spelling replacement.

Commit 8704dde8 mistakenly removed this part of code -- it is not dead,
it is just that it will only fire when the user answered No at some of
the replacement prompts.  So... when we've rereached the starting line,
a found occurrence is invalid when it is beyond the starting x (either
after or before it, dependending on the direction of search).

This fixes https://savannah.gnu.org/bugs/?47816.

For a little contrast with the function edit_refresh() -- it's
annoying that when you search for the latter you get to see all
the settings of the flag too.

The function edit_update() is called by edit_refresh() itself, so it is
silly that the first sets 'edit_refresh_needed' to TRUE.  This setting
is needed only in a few cases -- in the others it's not needed because
the screen does not need to be refreshed (it was just about positioning
the cursor), or 'edit_refresh_needed' has already been set by a call to
goto_line_posx().  So, just set the flag in the five places that need it
and spare the other four calls.

Instead of saving the current value of placewewant, then setting the
new value, and then passing the old value to edit_redraw() in seven
different places, just let edit_redraw() do this saving and setting.

In the bargain placewewant is now only recalculated when it matters
-- when allow_update is TRUE -- and not when it's superfluous.