This refactors all instances of bitwise-ANDs with `~MOD_MASK'. There is
a handful of more complex instances I left unchanged (in cube.c, midend.c,
and twiddle.c), since those AND with `~MOD_MASK | MOD_NUM_KEYPAD' or
similar. I don't think it's worth writing a macro for those cases.
Also document this new macro's usage in devel.but.
This adds an extra parameter to move_cursor() that's an optional pointer
to a bool indicating whether the cursor is visible. This allows for
centralising the common idiom of having the keyboard cursor become
visible when a cursor key is pressed. Consistently with the vast
majority of existing puzzles, the cursor moves even if it was invisible
before, and becomes visible even if it can't move.
The function now also returns one of the special constants that can be
returned by interpret_move(), so that the caller can correctly return
MOVE_UI_UPDATE or MOVE_NO_EFFECT without needing to carefully check for
changes itself.
Callers are updated only to the extent that they all pass NULL as the
new argument. Most of them could now be substantially simplified.
Pearl generally has to generate quite a lot of candidate loops before
it can find one that makes a viable puzzle. Before this change it
generated a new grid structure for each of those candidate loops. The
result was that grid_new() accounted for over 5% of the
puzzle-generation time.
Pulling grid_new() out of the loop-generation loop makes "pearl
--generate 100 8x8dt#0" about 6% faster on my laptop, while producing
precisely the same output. Most of this change is just renaming the
"grid" variable in new_clues() so it doesn't collide with the typedef
of the same name.
Previously, the 'faces', 'edges' and 'dots' arrays in a grid structure
were arrays of actual grid_face, grid_edge and grid_dot structures,
physically containing all the data about the grid. But they also
referred to each other by pointers, which meant that they were hard to
realloc larger (you'd have to go through and rewrite all the pointers
whenever the base of an array moved). And _that_ meant that every grid
type had to figure out a reasonably good upper bound on the number of
all those things it was going to need, so that it could allocate those
arrays the right size to begin with, and not have to grow them
painfully later.
For some grid types - particularly the new aperiodic ones - that was
actually a painful part of the job. So I think enough is enough:
counting up how much memory you're going to need before using it is a
mug's game, and we should instead realloc on the fly.
So now g->faces, g->edges and g->dots have an extra level of
indirection. Instead of being arrays of actual structs, they're arrays
of pointers, and each struct in them is individually allocated. Once a
grid_face has been allocated, it never moves again, even if the array
of pointers changes size.
The old code had a common idiom of recovering the array index of a
particular element by subtracting it from the array base, e.g. writing
'f - g->faces' or 'e - g->edges'. To make that lookup remain possible,
I've added an 'index' field to each sub-structure, which is
initialised at the point where we decide what array index it will live
at.
This should involve no functional change, but the code that previously
had to figure out max_faces and max_dots up front for each grid type
is now completely gone, and nobody has to solve those problems in
advance any more.
In Pearl, a mouse-down outside the grid sets ui->ndragcoords to -1.
The intended effect of this is to make sure that future drags are
ignored, so you can't try to draw a line starting off the grid.
However, this also has the effect of clearing any in-progress drag.
This can happen if there's a keyboard "drag" in progress at the time.
This is arguably wrong, but much more wrong was that interpret_move
returned MOVE_UNUSED (and previously NULL) in this case. That meant
that the display didn't get updated to show the abandonment of the
drag, or the removal of the keyboard cursor that also happened. This
commit changes MOVE_UNUSED to MOVE_UI_UPDATE so that at least the
effect is correctly visible.
All the other constants named UI_* are special key names that can be
passed to midend_process_key(), but UI_UPDATE is a special return value
from the back-end interpret_move() function instead. This renaming
makes the distinction clear and provides a naming convention for future
special return values from interpret_move().
This will be necessary in the next commit, so that the midend can make
a game_ui out of nothing in order to store preferences in it.
The only game actually affected by this requirement is Pearl, which
has a preference (GUI style) and also allocates space based on the
game_state's grid size to store the coordinates of a path being
dragged, so if there is no game_state, it can't do the latter - which
is OK, because it also won't be expected to.
These are similar to the existing pair configure() and custom_params()
in that get_prefs() returns an array of config_item describing a set
of dialog-box controls to present to the user, and set_prefs()
receives the same array with answers filled in and implements the
answers. But where configure() and custom_params() operate on a
game_params structure, the new pair operate on a game_ui, and are
intended to permit GUI configuration of all the settings I just moved
into that structure.
However, nothing actually _calls_ these routines yet. All I've done in
this commit is to add them to 'struct game' and implement them for the
functions that need them.
Also, config_item has new fields, permitting each config option to
define a machine-readable identifying keyword as well as the
user-facing description. For options of type C_CHOICES, each choice
also has a keyword. These keyword fields are only defined at all by
the new get_prefs() function - they're left uninitialised in existing
uses of the dialog system. The idea is to use them when writing out
the user's preferences into a configuration file on disk, although I
haven't actually done any of that work in this commit.
Environment variables that set specific settings of particular
puzzles, such as SLANT_SWAP_BUTTONS, LIGHTUP_LIT_BLOBS and
LOOPY_AUTOFOLLOW, now all affect the game behaviour via fields in
game_ui instead of being looked up by getenv in the individual
functions that need to know them.
The purpose of this refactoring is to put those config fields in a
place where other more user-friendly configuration systems will also
be able to access them, once I introduce one. However, for the moment,
there's no functional change: I haven't _yet_ changed how the user
sets those options. They're still set by environment variables alone.
All I'm changing here is where the settings are stored inside the
code, and exactly when they're read out of the environment to put into
the game_ui.
Specifically, the getenvs now happen during new_ui(). Or rather, in
all the puzzles I've changed here, they happen in a subroutine
legacy_prefs_override() called from within new_ui(), after it's set up
the default values for the settings, and then gives the environment a
chance to override them. Or rather, legacy_prefs_override() only
actually calls getenv the first time, and after that, it's cached the
answers it got.
In order to make the override functions less wordy, I've altered the
prototype of getenv_bool so that it returns an int rather than a bool,
and takes its default return value in the same form. That way you can
set the default to something other than 0 or 1, and find out whether a
value was present at all.
This commit only touches environment configuration specific to an
individual puzzle. The midend also has some standard environment-based
config options that apply to all puzzles, such as colour scheme and
default presets and preset-menu extension. I haven't handled those
yet.
I'm about to move some of the bodgy getenv-based options so that they
become fields in game_ui. So these functions, which could previously
access those options directly via getenv, will now need to be given a
game_ui where they can look them up.
This is preparing to separate out the auxiliary functionality, and
perhaps leave space for making more of it in future.
The previous name 'edsf' was too vague: the 'e' stood for 'extended',
and didn't say anything about _how_ it was extended. It's now called a
'flip dsf', since it tracks whether elements in the same class are
flipped relative to each other. More importantly, clients that are
going to use the flip tracking must say so when they allocate the dsf.
And Keen's need to track the minimal element of an equivalence class
is going to become a non-default feature, so there needs to be a new
kind of dsf that specially tracks those, and Keen will have to call it.
While I'm here, I've renamed the three dsf creation functions so that
they start with 'dsf_' like all the rest of the dsf API.
Now that the dsf knows its own size internally, there's no need to
tell it again when one is copied or reinitialised.
This makes dsf_init much more about *re*initialising a dsf, since now
dsfs are always allocated using a function that will initialise them
anyway. So I think it deserves a rename.
In this commit, 'DSF' is simply a typedef for 'int', so that the new
declaration form 'DSF *' translates to the same type 'int *' that dsfs
have always had. So all we're doing here is mechanically changing type
declarations throughout the code.
The majority of back-ends define encode_ui() to return NULL and
decode_ui() to do nothing. This commit allows them to instead specify
the relevant function pointers as NULL, in which case the mid-end won't
try to call them.
I'm planning to add a parameter to decode_ui(), and if I'm going to have
to touch every back-end's version of decode_ui(), I may as well ensure
that most of them never need to be touched again. And obviously
encode_ui() should go the same way for symmetry.
This fixes a build failure introduced by commit 2e48ce132e011e8
yesterday.
When I saw that commit I expected the most likely problem would be in
the NestedVM build, which is currently the thing with the most most
out-of-date C implementation. And indeed the NestedVM toolchain
doesn't have <tgmath.h> - but much more surprisingly, our _Windows_
builds failed too, with a compile error inside <tgmath.h> itself!
I haven't looked closely into the problem yet. Our Windows builds are
done with clang, which comes with its own <tgmath.h> superseding the
standard Windows one. So you'd _hope_ that clang could make sense of
its own header! But perhaps the problem is that this is an unusual
compile mode and hasn't been tested.
My fix is to simply add a cmake check for <tgmath.h> - which doesn't
just check the file's existence, it actually tries compiling a file
that #includes it, so it will detect 'file exists but is mysteriously
broken' just as easily as 'not there at all'. So this makes the builds
start working again, precisely on Ben's theory of opportunistically
using <tgmath.h> where possible and falling back to <math.h>
otherwise.
It looks ugly, though! I'm half tempted to make a new header file
whose job is to include a standard set of system headers, just so that
that nasty #ifdef doesn't have to sit at the top of almost all the
source files. But for the moment this at least gets the build working
again.
C89 provided only double-precision mathematical functions (sin() etc),
and so despite using single-precision elsewhere, those are what Puzzles
has traditionally used. C99 introduced single-precision equivalents
(sinf() etc), and I hope it's been long enough that we can safely use
them. Maybe they'll even be faster.
Rather than directly use the single-precision functions, though, we use
the magic macros from <tgmath.h> that automatically choose the precision
of mathematical functions based on their arguments. This has the
advantage that we only need to change which header we include, and thus
that we can switch back again if some platform has trouble with the new
header.
If you define PUZZLES_INITIAL_CURSOR=y, puzzles that have a keyboard
cursor will default to making it visible rather than invisible at the
start of a new game. Behaviour is otherwise the same, so mouse actions
will cause the cursor to vanish and keyboard actions will cause it to
appear. It's just the default that has changed.
The purpose of this is for use on devices and platforms where the
primary or only means of interaction is keyboard-based. In those cases,
starting with the keyboard cursor invisible is weird and a bit
confusing.
This provides a standard way to get a boolean from an environment
variable. It treats the variable as true iff its value begins with 'y'
or 'Y', like most of the current implementations. The function takes a
default value which it returns if the environment variable is undefined.
This replaces the various ad-hoc tests of environment variable scattered
around and mostly doesn't change their behaviour. The exceptions are
TOWERS_2D in Towers and DEBUG_PUZZLES in the Windows front end. Both of
those were treated as true if they were defined at all, but now follow
the same rules as other boolean environment variables.
After Ben fixed all the unwanted global functions by using gcc's
-Wmissing-declarations to spot any that were not predeclared, I
remembered that clang has -Wmissing-variable-declarations, which does
the same job for global objects. Enabled it in -DSTRICT=ON, and made
the code clean under it.
Mostly this was just a matter of sticking 'static' on the front of
things. One variable was outright removed ('verbose' in signpost.c)
because after I made it static clang was then able to spot that it was
also unused.
The more interesting cases were the ones where declarations had to be
_added_ to header files. In particular, in COMBINED builds, puzzles.h
now arranges to have predeclared each 'game' structure defined by a
puzzle backend. Also there's a new tiny header file gtk.h, containing
the declarations of xpm_icons and n_xpm_icons which are exported by
each puzzle's autogenerated icon source file and by no-icon.c. Happily
even the real XPM icon files were generated by our own Perl script
rather than being raw xpm output from ImageMagick, so there was no
difficulty adding the corresponding #include in there.
A Pearl move string contains a sequence of sub-moves, each of which
can affect the state of the connection between the centre of a square
and one of its edges. interpret_move() generates these in pairs so
that the two halves of a connection between the centres of adjacent
squares stay in the same state.
If, however, a save file contains mismatched half-moves,
execute_move() should ideally return NULL rather than causing an
assertion failure. This has to be checked at the end of the whole
move string, so I've arranged for check_completion() to return a
boolean indicating whether the current state (and hence the move
preceding it) is valid. It now returns 'false' when a connection
stops at a square boundary or when it goes off the board. These
conditions used to be assertion failures, and now they just cause the
move to be rejected.
This supersedes the check for off-board connections added in 15f4fa8,
since now check_completion() can check for off-board links for the
whole board at once.
This save file trivially demonstrates the problem, causing
"dsf_update_completion: Assertion `state->lines[bc] & F(dir)' failed"
without this fix:
SAVEFILE:41:Simon Tatham's Portable Puzzle Collection
GAME :5:Pearl
PARAMS :5:6x6t0
CPARAMS :5:6x6t0
DESC :17:BbBfWceBbWaBWWgWB
NSTATES :1:2
STATEPOS:1:2
MOVE :6:R1,0,0
Similarly to the previous commit, if you started Pearl with at least
some kinds of invalid puzzle (e.g. "6x6:abBfWcWWrBa") and then pressed
'h' to get hints, you could provoke an assertion failure. But this
time the assertion wasn't in the solver itself; the solver gave up
gracefully and didn't crash, but it _did_ leave the links between
squares in the game_state in an inconsistent state, in that one square
was marked as linking to its neighbour without the neighbour also
linking back to it. This caused the /* should have reciprocal link */
assertion in dsf_update_completion to fail, when that was called from
check_completion after the solver had finished, to decide whether the
puzzle was now solved.
In this commit, I arrange that whether or not pearl_solve returns a
grid layout that's legal by the rules of the _puzzle_, it at least
returns one that's legal by the rules of the _data representation_, in
that every link between squares is either bidirectional or absent.
This is a better solution than just removing the assertion, because if
the inconsistent data were allowed to persist, it would lead to
further problems in gameplay. For example, if you just remove that
assertion instead of this fix and press 'h' on the example puzzle id
above, you'll find that the non-reciprocal links are actually visible,
in the form of several thick lines that stop at a grid square boundary
instead of connecting two square-centres. (It looks even sillier if
you set PEARL_GUI_LOOPY=y.)
That's a situation that can't be created by a normal move, and if you
try to make normal moves after it (e.g. click one of the weird edges),
you'll find that both sides of the half-link get toggled, so now it's
a half-link the other way round. So not only can't you _create_ this
situation in normal play, you can't get rid of it either!
That assertion in dsf_update_completion was commented out at one
point, and I put it back in commit c5500926bf7458a saying that if it
failed I'd like to know about it. And indeed, I'm glad I did, because
this kind of unfixable wrongness in the resulting game_state was worth
noticing and getting rid of!
While they couldn't be generated in normal play, execute_move() would
permit lines and marks across the edge of the grid that would then
generate assertion failures ("dsf_update_completion: Assertion
`INGRID(state, bx, by)' failed.").
I've added a check to execute_move() that after updating a square, the
square doesn't have any lines or marks that leave the grid.
This save file demonstrated the problem:
SAVEFILE:41:Simon Tatham's Portable Puzzle Collection
VERSZON :1:1
GAME :5:Pearl
PARAMS :5:5x6dt
CPARAMS :5:5x6dt
DESC :6:eeeeee
NSTATES :1:2
STATEPOS:1:1
MOVE :6:F1,4,2
If can_configure is false, then the game's configure() and
custom_params() functions will never be called. If can_solve is false,
solve() will never be called. If can_format_as_text_ever is false,
can_format_as_text_now() and text_format() will never be called. If
can_print is false, print_size() and print() will never be called. If
is_timed is false, timing_state() will never be called.
In each case, almost all puzzles provided a function nonetheless. I
think this is because in Puzzles' early history there was no "game"
structure, so the functions had to be present for linking to work. But
now that everything indirects through the "game" structure, unused
functions can be left unimplemented and the corresponding pointers set
to NULL.
So now where the flags mentioned above are false, the corresponding
functions are omitted and the function pointers in the "game" structures
are NULL.
This provides a way for the front end to ask how a particular key should
be labelled right now (specifically, for a given game_state and
game_ui). This is useful on feature phones where it's conventional to
put a small caption above each soft key indicating what it currently
does.
The function currently provides labels only for CURSOR_SELECT and
CURSOR_SELECT2. This is because these are the only keys that need
labelling on KaiOS.
The concept of labelling keys also turns up in the request_keys() call,
but there are quite a few differences. The labels returned by
current_key_label() are dynamic and likely to vary with each move, while
the labels provided by request_keys() are constant for a given
game_params. Also, the keys returned by request_keys() don't generally
include CURSOR_SELECT and CURSOR_SELECT2, because those aren't necessary
on platforms with pointing devices. It might be possible to provide a
unified API covering both of this, but I think it would be quite
difficult to work with.
Where a key is to be unlabelled, current_key_label() is expected to
return an empty string. This leaves open the possibility of NULL
indicating a fallback to button2label or the label specified by
request_keys() in the future.
It's tempting to try to implement current_key_label() by calling
interpret_move() and parsing its output. This doesn't work for two
reasons. One is that interpret_move() is entitled to modify the
game_ui, and there isn't really a practical way to back those changes
out. The other is that the information returned by interpret_move()
isn't sufficient to generate a label. For instance, in many puzzles it
generates moves that toggle the state of a square, but we want the label
to reflect which state the square will be toggled to. The result is
that I've generally ended up pulling bits of code from interpret_move()
and execute_move() together to implement current_key_label().
Alongside the back-end function, there's a midend_current_key_label()
that's a thin wrapper around the back-end function. It just adds an
assertion about which key's being requested and a default null
implementation so that back-ends can avoid defining the function if it
will do nothing useful.
When there's no drag in progress, cancelling the drag has no effect.
Returning NULL lets the front-end know this, which in particular means
the Backspace key can leave the app in KaiOS.
Josh Triplett reported:
> If I ask pearl to generate a 5x5 tricky puzzle, it runs forever.
I find that 5x6 or 6x5 works, so set the minimum accordingly.
References: https://bugs.debian.org/667963
interpret_ui_drag is now called from update_ui_drag, so it makes more
sense to have the former appear first in the file, together with its
comment explaining the expected usage.
A user reported recently that they were trying this as an extra
challenge (solve the whole puzzle mentally and then draw it in
finished form in one UI action). But the backtracking behaviour of
Pearl's dragging mode meant that the loop erased itself as soon as the
drag came back to a revisited position.
In this commit I fix that by making the exception that you can
unconditionally return to the start point of the drag, _provided_ that
in doing so you don't create a grid cell of degree > 2.
Most of these aren't especially useful, but if we're going to have
them in the code base at all, we should at least ensure they compile:
bit-rotted conditioned-out code is of no value.
One of the new programs is 'galaxieseditor', which borrows most of the
Galaxies code but changes the UI so that you can create and remove
_dots_ instead of edges, and then run the solver to see whether it can
solve the puzzle you've designed. Unlike the rest, this is a GUI
helper tool, using the 'guiprogram' cmake function introduced in the
previous commit.
The programs are:
- 'combi', a test program for the utility module that generates all
combinations of n things
- 'divvy', a test program for the module that divides a rectangle at
random into equally-sized polyominoes
- 'penrose-test', a test program for the Penrose-tiling generator
used in Loopy, which outputs an SVG of a piece of tiling
- 'penrose-vector', a much smaller test program for the vector
arithmetic subroutines in that code
- 'sort-test', a test of this code base's local array sorting routine
- 'tree234-test', the exhaustive test code that's been in tree234.c
all along.
Not all of them compiled first time. Most of the fixes were the usual
kind of thing: fixing compiler warnings by removing unused
variables/functions, bringing uses of internal APIs up to date. A
notable one was that galaxieseditor's interpret_move() modified the
input game state, which was an error all along and is now detected by
me having made it a const pointer; I had to replace that with an extra
wrinkle in the move-string format, so that now execute_move() makes
the modification.
The one I'm _least_ proud of is squelching a huge number of
format-string warnings in tree234-test by interposing a variadic
function without __attribute__((printf)).
I don't know how I've never thought of this before! Pretty much every
game in this collection has to have a mechanism for noticing when
game_redraw is called for the first time on a new drawstate, and if
so, start by covering the whole window with a filled rectangle of the
background colour. This is a pain for implementers, and also awkward
because the drawstate often has to _work out_ its own pixel size (or
else remember it from when its size method was called).
The backends all do that so that the frontends don't have to guarantee
anything about the initial window contents. But that's a silly
tradeoff to begin with (there are way more backends than frontends, so
this _adds_ work rather than saving it), and also, in this code base
there's a standard way to handle things you don't want to have to do
in every backend _or_ every frontend: do them just once in the midend!
So now that rectangle-drawing operation happens in midend_redraw, and
I've been able to remove it from almost every puzzle. (A couple of
puzzles have other approaches: Slant didn't have a rectangle-draw
because it handles even the game borders using its per-tile redraw
function, and Untangle clears the whole window on every redraw
_anyway_ because it would just be too confusing not to.)
In some cases I've also been able to remove the 'started' flag from
the drawstate. But in many cases that has to stay because it also
triggers drawing of static display furniture other than the
background.
The Rockbox frontend allows games to be displayed in a "zoomed-in"
state targets with small displays. Currently we use a modal interface
-- a "viewing" mode in which the cursor keys are used to pan around
the rendered bitmap; and an "interaction" mode that actually sends
keys to the game.
This commit adds a midend_get_cursor_location() function to allow the
frontend to retrieve the backend's cursor location or other "region of
interest" -- such as the player location in Cube or Inertia.
With this information, the Rockbox frontend can now intelligently
follow the cursor around in the zoomed-in state, eliminating the need
for a modal interface.
Another thing I spotted while trawling the whole source base was that
a couple of games had omitted 'static' on a lot of their internal
functions. Checking with nm, there turned out to be quite a few more
than I'd spotted by eye, so this should fix them all.
Also added one missing 'const', on the lookup table nbits[] in Tracks.
This is the main bulk of this boolification work, but although it's
making the largest actual change, it should also be the least
disruptive to anyone interacting with this code base downstream of me,
because it doesn't modify any interface between modules: all the
inter-module APIs were updated one by one in the previous commits.
This just cleans up the code within each individual source file to use
bool in place of int where I think that makes things clearer.
This commit removes the old #defines of TRUE and FALSE from puzzles.h,
and does a mechanical search-and-replace throughout the code to
replace them with the C99 standard lowercase spellings.
encode_params, validate_params and new_desc now take a bool parameter;
fetch_preset, can_format_as_text_now and timing_state all return bool;
and the data fields is_timed, wants_statusbar and can_* are all bool.
All of those were previously typed as int, but semantically boolean.
This commit changes the API declarations in puzzles.h, updates all the
games to match (including the unfinisheds), and updates the developer
docs as well.
This function gives the front end a way to find out what keys the back
end requires; and as such it is mostly useful for ports without a
keyboard. It is based on changes originally found in Chris Boyle's
Android port, though some modifications were needed to make it more
flexible.
This allows me to use different types for the mutable, dynamically
allocated string value in a C_STRING control and the fixed constant
list of option names in a C_CHOICES.
Now midend.c directly tests the returned pointer for equality to this
value, instead of checking whether it's the empty string.
A minor effect of this is that games may now return a dynamically
allocated empty string from interpret_move() and treat it as just
another legal move description. But I don't expect anyone to be
perverse enough to actually do that! The main purpose is that it
avoids returning a string literal from a function whose return type is
a pointer to _non-const_ char, i.e. we are now one step closer to
being able to make this code base clean under -Wwrite-strings.
To do this, I've completely replaced the API between mid-end and front
end, so any downstream front end maintainers will have to do some
rewriting of their own (sorry). I've done the necessary work in all
five of the front ends I keep in-tree here - Windows, GTK, OS X,
Javascript/Emscripten, and Java/NestedVM - and I've done it in various
different styles (as each front end found most convenient), so that
should provide a variety of sample code to show downstreams how, if
they should need it.
I've left in the old puzzle back-end API function to return a flat
list of presets, so for the moment, all the puzzle backends are
unchanged apart from an extra null pointer appearing in their
top-level game structure. In a future commit I'll actually use the new
feature in a puzzle; perhaps in the further future it might make sense
to migrate all the puzzles to the new API and stop providing back ends
with two alternative ways of doing things, but this seemed like enough
upheaval for one day.
I was accidentally re-checking the value of component_state[comp]
after resetting comp to the special value -1, which caused a failure
to highlight stray path-shaped components if they existed in addition
to a large loop component. (Plus, of course, it's just illegal no
matter what visible behaviour it does or doesn't cause in practice.)
Fixed by adjusting the code to more closely match the version in Loopy
(I wonder how I managed to add two pieces of code in commit b31155b73
without noticing this difference between them).
In commits 24848706e and adc54741f, I revamped the highlighting of
erroneous connected components of those two puzzles' solution graphs
in cases where a non-solution loop existed, so that the largest
component was considered correct and the smaller ones lit up in red.
I intended this to work in the cases where you have most of a correct
solution as one component and a small spurious loop as another (in
which case the latter lights up red), or conversely where your mostly
correct component was joined into a loop leaving a few edges out (in
which case the left-out edges again light up red). However, a user
points out that I overlooked the case where your mostly correct
solution is not all one component! If you've got lots of separate
pieces of path, and one tiny loop that's definitely wrong, it's silly
to light up all but the longest piece of path as if they're erroneous.
Fixed by treating all the non-loop components as one unit for these
purposes. So if there is at least one loop and it isn't the only thing
on the board, then we _either_ light up all loops (if they're all
smaller than the set of non-loop paths put together), _or_ light up
everything but the largest loop (if that loop is the biggest thing on
the board).
Pearl has more or less the same attitude to loops as Loopy does, in
that a loop is required in the solution but some loops during play
want to be highlighted as errors. So it makes sense to use the same
strategy for loop highlighting.
I've cloned-and-hacked the code from Loopy rather than abstracting it
out, because there were some fiddly differences in application (like
checking of untouched clues in Pearl). Perhaps some day I can come
back and make it all neater.
Also, while I'm here, I've cleaned up the loop_length field in
game_state, which was carefully set up by check_completion() but never
actually used for anything. (If I remember rightly, it was going to be
used for a fancy victory flash which never saw the light of day.)
I think this assertion must have been put under '#if 0' during early
development, and accidentally never taken out once the game started
actually working. Putting it back in doesn't cause the self-tests to
fail, so I'm reinstating it - if it does fail, I'd like to know about
it!
