From 1cea529f7dc604c05ae5d8a86c736e37fedd88aa Mon Sep 17 00:00:00 2001
From: simon <simon@cda61777-01e9-0310-a592-d414129be87e>
Date: Sun, 19 Jun 2011 13:43:35 +0000
Subject: [PATCH] Changed my mind about midend_is_solved: I've now reprototyped
 it as midend_status(), and given it three return codes for win, (permanent)
 loss and game-still-in-play. Depending on what the front end wants to use it
 for, it may find any or all of these three states worth distinguishing from
 each other.

(I suppose a further enhancement might be to add _non_-permanent loss
as a fourth distinct status, to describe situations in which you can't
play further without pressing Undo but doing so is not completely
pointless. That might reasonably include dead-end situations in Same
Game and Pegs, and blown-self-up situations in Mines and Inertia.
However, I haven't done this at present.)


git-svn-id: svn://svn.tartarus.org/sgt/puzzles@9179 cda61777-01e9-0310-a592-d414129be87e
---
 blackbox.c            | 22 ++++++++++++++-------
 bridges.c             |  6 +++---
 cube.c                |  6 +++---
 devel.but             | 53 +++++++++++++++++++++++++++++----------------------
 dominosa.c            |  6 +++---
 fifteen.c             |  6 +++---
 filling.c             |  6 +++---
 flip.c                |  6 +++---
 galaxies.c            |  6 +++---
 guess.c               | 23 +++++++++++-----------
 inertia.c             | 12 ++++++------
 keen.c                |  6 +++---
 lightup.c             |  6 +++---
 loopy.c               |  6 +++---
 magnets.c             |  6 +++---
 map.c                 |  6 +++---
 midend.c              |  8 +++++---
 mines.c               | 11 ++++++++---
 net.c                 |  6 +++---
 netslide.c            |  6 +++---
 nullgame.c            |  6 +++---
 pattern.c             |  6 +++---
 pegs.c                | 10 +++++++---
 puzzles.h             |  4 ++--
 range.c               |  6 +++---
 rect.c                |  6 +++---
 samegame.c            | 11 +++++------
 signpost.c            |  6 +++---
 singles.c             |  6 +++---
 sixteen.c             |  6 +++---
 slant.c               |  6 +++---
 solo.c                |  6 +++---
 tents.c               |  6 +++---
 towers.c              |  6 +++---
 twiddle.c             |  6 +++---
 unequal.c             |  6 +++---
 unfinished/group.c    |  6 +++---
 unfinished/pearl.c    |  6 +++---
 unfinished/separate.c |  6 +++---
 unfinished/slide.c    |  6 +++---
 unfinished/sokoban.c  |  6 +++---
 untangle.c            |  6 +++---
 42 files changed, 188 insertions(+), 164 deletions(-)

diff --git a/blackbox.c b/blackbox.c
index 305feac..be79634 100644
--- a/blackbox.c
+++ b/blackbox.c
@@ -1462,13 +1462,21 @@ static float game_flash_length(game_state *oldstate, game_state *newstate,
         return 0.0F;
 }
 
-static int game_is_solved(game_state *state)
+static int game_status(game_state *state)
 {
-    /*
-     * We return true whenever the solution has been revealed, even
-     * (on spoiler grounds) if it wasn't guessed correctly.
-     */
-    return state->reveal;
+    if (state->reveal) {
+        /*
+         * We return nonzero whenever the solution has been revealed,
+         * even (on spoiler grounds) if it wasn't guessed correctly.
+         */
+        if (state->nwrong == 0 &&
+            state->nmissed == 0 &&
+            state->nright >= state->minballs)
+            return +1;
+        else
+            return -1;
+    }
+    return 0;
 }
 
 static int game_timing_state(game_state *state, game_ui *ui)
@@ -1519,7 +1527,7 @@ const struct game thegame = {
     game_redraw,
     game_anim_length,
     game_flash_length,
-    game_is_solved,
+    game_status,
     FALSE, FALSE, game_print_size, game_print,
     TRUE,			       /* wants_statusbar */
     FALSE, game_timing_state,
diff --git a/bridges.c b/bridges.c
index 8e61400..5860e0c 100644
--- a/bridges.c
+++ b/bridges.c
@@ -2713,9 +2713,9 @@ static float game_flash_length(game_state *oldstate, game_state *newstate,
     return 0.0F;
 }
 
-static int game_is_solved(game_state *state)
+static int game_status(game_state *state)
 {
-    return state->completed;
+    return state->completed ? +1 : 0;
 }
 
 static int game_timing_state(game_state *state, game_ui *ui)
@@ -2821,7 +2821,7 @@ const struct game thegame = {
     game_redraw,
     game_anim_length,
     game_flash_length,
-    game_is_solved,
+    game_status,
     TRUE, FALSE, game_print_size, game_print,
     FALSE,			       /* wants_statusbar */
     FALSE, game_timing_state,
diff --git a/cube.c b/cube.c
index 9b70487..cac4640 100644
--- a/cube.c
+++ b/cube.c
@@ -1708,9 +1708,9 @@ static float game_flash_length(game_state *oldstate,
     return 0.0F;
 }
 
-static int game_is_solved(game_state *state)
+static int game_status(game_state *state)
 {
-    return state->completed;
+    return state->completed ? +1 : 0;
 }
 
 static int game_timing_state(game_state *state, game_ui *ui)
@@ -1761,7 +1761,7 @@ const struct game thegame = {
     game_redraw,
     game_anim_length,
     game_flash_length,
-    game_is_solved,
+    game_status,
     FALSE, FALSE, game_print_size, game_print,
     TRUE,			       /* wants_statusbar */
     FALSE, game_timing_state,
diff --git a/devel.but b/devel.but
index 9438e0e..806ac63 100644
--- a/devel.but
+++ b/devel.but
@@ -1224,27 +1224,33 @@ a mine from the colour it uses when you complete the game. In order
 to achieve this, its \cw{flash_length()} function has to store a
 flag in the \c{game_ui} to indicate which flash type is required.)
 
-\S{backend-is-solved} \cw{is_solved()}
+\S{backend-status} \cw{status()}
 
-\c int (*is_solved)(game_state *state);
+\c int (*status)(game_state *state);
 
-This function returns \cw{TRUE} if the game represented by \cw{state}
-is currently in a solved state. The mid-end uses this to implement
-\cw{midend_is_solved()} (\k{midend-is-solved}).
+This function returns a status value indicating whether the current
+game is still in play, or has been won, or has been conclusively lost.
+The mid-end uses this to implement \cw{midend_status()}
+(\k{midend-status}).
 
-Front ends may wish to use this as a cue to proactively offer the
-option of starting a new game. Therefore, back ends should consider
-returning \cw{TRUE} in situations where the game is \e{lost} as well
-as won, if losing makes it unlikely that the player would play on.
+The return value should be +1 if the game has been successfully
+solved. If the game has been lost in a situation where further play is
+unlikely, the return value should be -1. If neither is true (so play
+is still ongoing), return zero.
+
+Front ends may wish to use a non-zero status as a cue to proactively
+offer the option of starting a new game. Therefore, back ends should
+not return -1 if the game has been \e{technically} lost but undoing
+and continuing is still a realistic possibility.
 
 (For instance, games with hidden information such as Guess or Mines
-might well set this flag whenever they reveal the solution, whether or
-not the player guessed it correctly, on the grounds that a player
-would be unlikely to hide the solution and continue playing after the
-answer was spoiled. On the other hand, games where you can merely get
-into a dead end such as Same Game or Inertia might choose not to, on
-the grounds that the player would quite likely press Undo and carry on
-playing.)
+might well return a non-zero status whenever they reveal the solution,
+whether or not the player guessed it correctly, on the grounds that a
+player would be unlikely to hide the solution and continue playing
+after the answer was spoiled. On the other hand, games where you can
+merely get into a dead end such as Same Game or Inertia might choose
+to return 0 in that situation, on the grounds that the player would
+quite likely press Undo and carry on playing.)
 
 \S{backend-redraw} \cw{redraw()}
 
@@ -3118,18 +3124,19 @@ The front end can expect its drawing API and/or
 \cw{activate_timer()} to be called from within a call to this
 function.
 
-\H{midend-is-solved} \cw{midend_is_solved()}
+\H{midend-status} \cw{midend_status()}
 
-\c int midend_is_solved(midend *me);
+\c int midend_status(midend *me);
 
-This function returns \cw{TRUE} if the midend is currently displaying
-a game in a solved state, according to the back end's \cw{is_solved()}
+This function returns +1 if the midend is currently displaying a game
+in a solved state, -1 if the game is in a permanently lost state, or 0
+otherwise. This function just calls the back end's \cw{status()}
 function. Front ends may wish to use this as a cue to proactively
 offer the option of starting a new game.
 
-(See \k{backend-is-solved} for more detail about the back end's
-\cw{is_solved()} function and discussion of what should count as
-\q{solved} anyway).
+(See \k{backend-status} for more detail about the back end's
+\cw{status()} function and discussion of what should count as which
+status code.)
 
 \H{midend-can-undo} \cw{midend_can_undo()}
 
diff --git a/dominosa.c b/dominosa.c
index 21d4b67..02e276c 100644
--- a/dominosa.c
+++ b/dominosa.c
@@ -1535,9 +1535,9 @@ static float game_flash_length(game_state *oldstate, game_state *newstate,
     return 0.0F;
 }
 
-static int game_is_solved(game_state *state)
+static int game_status(game_state *state)
 {
-    return state->completed;
+    return state->completed ? +1 : 0;
 }
 
 static int game_timing_state(game_state *state, game_ui *ui)
@@ -1628,7 +1628,7 @@ const struct game thegame = {
     game_redraw,
     game_anim_length,
     game_flash_length,
-    game_is_solved,
+    game_status,
     TRUE, FALSE, game_print_size, game_print,
     FALSE,			       /* wants_statusbar */
     FALSE, game_timing_state,
diff --git a/fifteen.c b/fifteen.c
index 338a993..5419f41 100644
--- a/fifteen.c
+++ b/fifteen.c
@@ -830,9 +830,9 @@ static float game_flash_length(game_state *oldstate,
         return 0.0F;
 }
 
-static int game_is_solved(game_state *state)
+static int game_status(game_state *state)
 {
-    return state->completed;
+    return state->completed ? +1 : 0;
 }
 
 static int game_timing_state(game_state *state, game_ui *ui)
@@ -883,7 +883,7 @@ const struct game thegame = {
     game_redraw,
     game_anim_length,
     game_flash_length,
-    game_is_solved,
+    game_status,
     FALSE, FALSE, game_print_size, game_print,
     TRUE,			       /* wants_statusbar */
     FALSE, game_timing_state,
diff --git a/filling.c b/filling.c
index 8b4a7c3..6a0abe9 100644
--- a/filling.c
+++ b/filling.c
@@ -1617,9 +1617,9 @@ static float game_flash_length(game_state *oldstate, game_state *newstate,
     return 0.0F;
 }
 
-static int game_is_solved(game_state *state)
+static int game_status(game_state *state)
 {
-    return state->completed;
+    return state->completed ? +1 : 0;
 }
 
 static int game_timing_state(game_state *state, game_ui *ui)
@@ -1720,7 +1720,7 @@ const struct game thegame = {
     game_redraw,
     game_anim_length,
     game_flash_length,
-    game_is_solved,
+    game_status,
     TRUE, FALSE, game_print_size, game_print,
     FALSE,				   /* wants_statusbar */
     FALSE, game_timing_state,
diff --git a/flip.c b/flip.c
index f8b96ae..6ba683b 100644
--- a/flip.c
+++ b/flip.c
@@ -1251,9 +1251,9 @@ static float game_flash_length(game_state *oldstate, game_state *newstate,
     return 0.0F;
 }
 
-static int game_is_solved(game_state *state)
+static int game_status(game_state *state)
 {
-    return state->completed;
+    return state->completed ? +1 : 0;
 }
 
 static int game_timing_state(game_state *state, game_ui *ui)
@@ -1304,7 +1304,7 @@ const struct game thegame = {
     game_redraw,
     game_anim_length,
     game_flash_length,
-    game_is_solved,
+    game_status,
     FALSE, FALSE, game_print_size, game_print,
     TRUE,			       /* wants_statusbar */
     FALSE, game_timing_state,
diff --git a/galaxies.c b/galaxies.c
index 77ef597..d8906b6 100644
--- a/galaxies.c
+++ b/galaxies.c
@@ -3348,9 +3348,9 @@ static float game_flash_length(game_state *oldstate, game_state *newstate,
         return 0.0F;
 }
 
-static int game_is_solved(game_state *state)
+static int game_status(game_state *state)
 {
-    return state->completed;
+    return state->completed ? +1 : 0;
 }
 
 static int game_timing_state(game_state *state, game_ui *ui)
@@ -3573,7 +3573,7 @@ const struct game thegame = {
     game_redraw,
     game_anim_length,
     game_flash_length,
-    game_is_solved,
+    game_status,
 #ifdef EDITOR
     FALSE, FALSE, NULL, NULL,
     TRUE,                              /* wants_statusbar */
diff --git a/guess.c b/guess.c
index 8cab1a4..a9fc134 100644
--- a/guess.c
+++ b/guess.c
@@ -43,7 +43,7 @@ struct game_state {
     pegrow solution;
     int next_go; /* from 0 to nguesses-1;
                     if next_go == nguesses then they've lost. */
-    int solved;
+    int solved;   /* +1 = win, -1 = lose, 0 = still playing */
 };
 
 static game_params *default_params(void)
@@ -790,7 +790,7 @@ static game_state *execute_move(game_state *from, char *move)
 
     if (!strcmp(move, "S")) {
 	ret = dup_game(from);
-	ret->solved = 1;
+	ret->solved = -1;
 	return ret;
     } else if (move[0] == 'G') {
 	p = move+1;
@@ -817,11 +817,11 @@ static game_state *execute_move(game_state *from, char *move)
 	nc_place = mark_pegs(ret->guesses[from->next_go], ret->solution, ret->params.ncolours);
 
 	if (nc_place == ret->solution->npegs) {
-	    ret->solved = 1; /* win! */
+	    ret->solved = +1; /* win! */
 	} else {
 	    ret->next_go = from->next_go + 1;
 	    if (ret->next_go >= ret->params.nguesses)
-		ret->solved = 1; /* 'lose' so we show the pegs. */
+		ret->solved = -1; /* lose, meaning we show the pegs. */
 	}
 
 	return ret;
@@ -1273,7 +1273,7 @@ static void game_redraw(drawing *dr, game_drawstate *ds, game_state *oldstate,
         currmove_redraw(dr, ds, state->next_go, COL_HOLD);
 
     /* draw the solution (or the big rectangle) */
-    if ((state->solved != ds->solved) || !ds->started) {
+    if ((!state->solved ^ !ds->solved) || !ds->started) {
         draw_rect(dr, SOLN_OX, SOLN_OY, SOLN_W, SOLN_H,
                   state->solved ? COL_BACKGROUND : COL_EMPTY);
         draw_update(dr, SOLN_OX, SOLN_OY, SOLN_W, SOLN_H);
@@ -1313,14 +1313,13 @@ static float game_flash_length(game_state *oldstate, game_state *newstate,
     return 0.0F;
 }
 
-static int game_is_solved(game_state *state)
+static int game_status(game_state *state)
 {
     /*
-     * We return true whenever the solution has been revealed, even
-     * (on spoiler grounds) if it wasn't guessed correctly.
-     *
-     * However, in that situation, 'solved' is still true, so we don't
-     * have to make any effort to arrange this.
+     * We return nonzero whenever the solution has been revealed, even
+     * (on spoiler grounds) if it wasn't guessed correctly. The
+     * correct return value from this function is already in
+     * state->solved.
      */
     return state->solved;
 }
@@ -1373,7 +1372,7 @@ const struct game thegame = {
     game_redraw,
     game_anim_length,
     game_flash_length,
-    game_is_solved,
+    game_status,
     FALSE, FALSE, game_print_size, game_print,
     FALSE,			       /* wants_statusbar */
     FALSE, game_timing_state,
diff --git a/inertia.c b/inertia.c
index d29a676..74fc3c1 100644
--- a/inertia.c
+++ b/inertia.c
@@ -2135,14 +2135,14 @@ static float game_flash_length(game_state *oldstate, game_state *newstate,
     return 0.0F;
 }
 
-static int game_is_solved(game_state *state)
+static int game_status(game_state *state)
 {
     /*
-     * If the player has died, we don't list the game as solved,
-     * because they're more likely to undo and carry on than to give
-     * up and start a new game.
+     * We never report the game as lost, on the grounds that if the
+     * player has died they're quite likely to want to undo and carry
+     * on.
      */
-    return !state->gems;
+    return state->gems == 0 ? +1 : 0;
 }
 
 static int game_timing_state(game_state *state, game_ui *ui)
@@ -2193,7 +2193,7 @@ const struct game thegame = {
     game_redraw,
     game_anim_length,
     game_flash_length,
-    game_is_solved,
+    game_status,
     FALSE, FALSE, game_print_size, game_print,
     TRUE,			       /* wants_statusbar */
     FALSE, game_timing_state,
diff --git a/keen.c b/keen.c
index 7984475..3776283 100644
--- a/keen.c
+++ b/keen.c
@@ -2005,9 +2005,9 @@ static float game_flash_length(game_state *oldstate, game_state *newstate,
     return 0.0F;
 }
 
-static int game_is_solved(game_state *state)
+static int game_status(game_state *state)
 {
-    return state->completed;
+    return state->completed ? +1 : 0;
 }
 
 static int game_timing_state(game_state *state, game_ui *ui)
@@ -2286,7 +2286,7 @@ const struct game thegame = {
     game_redraw,
     game_anim_length,
     game_flash_length,
-    game_is_solved,
+    game_status,
     TRUE, FALSE, game_print_size, game_print,
     FALSE,			       /* wants_statusbar */
     FALSE, game_timing_state,
diff --git a/lightup.c b/lightup.c
index 5d27fde..5fe95b0 100644
--- a/lightup.c
+++ b/lightup.c
@@ -2160,9 +2160,9 @@ static float game_flash_length(game_state *oldstate, game_state *newstate,
     return 0.0F;
 }
 
-static int game_is_solved(game_state *state)
+static int game_status(game_state *state)
 {
-    return state->completed;
+    return state->completed ? +1 : 0;
 }
 
 static int game_timing_state(game_state *state, game_ui *ui)
@@ -2267,7 +2267,7 @@ const struct game thegame = {
     game_redraw,
     game_anim_length,
     game_flash_length,
-    game_is_solved,
+    game_status,
     TRUE, FALSE, game_print_size, game_print,
     FALSE,			       /* wants_statusbar */
     FALSE, game_timing_state,
diff --git a/loopy.c b/loopy.c
index b84ca82..1f95f41 100644
--- a/loopy.c
+++ b/loopy.c
@@ -3780,9 +3780,9 @@ static float game_flash_length(game_state *oldstate, game_state *newstate,
     return 0.0F;
 }
 
-static int game_is_solved(game_state *state)
+static int game_status(game_state *state)
 {
-    return state->solved;
+    return state->solved ? +1 : 0;
 }
 
 static void game_print_size(game_params *params, float *x, float *y)
@@ -3918,7 +3918,7 @@ const struct game thegame = {
     game_redraw,
     game_anim_length,
     game_flash_length,
-    game_is_solved,
+    game_status,
     TRUE, FALSE, game_print_size, game_print,
     FALSE /* wants_statusbar */,
     FALSE, game_timing_state,
diff --git a/magnets.c b/magnets.c
index d932232..e49b7a5 100644
--- a/magnets.c
+++ b/magnets.c
@@ -2233,9 +2233,9 @@ static float game_flash_length(game_state *oldstate, game_state *newstate,
     return 0.0F;
 }
 
-static int game_is_solved(game_state *state)
+static int game_status(game_state *state)
 {
-    return state->completed;
+    return state->completed ? +1 : 0;
 }
 
 static int game_timing_state(game_state *state, game_ui *ui)
@@ -2373,7 +2373,7 @@ const struct game thegame = {
     game_redraw,
     game_anim_length,
     game_flash_length,
-    game_is_solved,
+    game_status,
     TRUE, FALSE, game_print_size, game_print,
     FALSE,			       /* wants_statusbar */
     FALSE, game_timing_state,
diff --git a/map.c b/map.c
index 556a9ec..5d170d1 100644
--- a/map.c
+++ b/map.c
@@ -3025,9 +3025,9 @@ static float game_flash_length(game_state *oldstate, game_state *newstate,
 	return 0.0F;
 }
 
-static int game_is_solved(game_state *state)
+static int game_status(game_state *state)
 {
-    return state->completed;
+    return state->completed ? +1 : 0;
 }
 
 static int game_timing_state(game_state *state, game_ui *ui)
@@ -3223,7 +3223,7 @@ const struct game thegame = {
     game_redraw,
     game_anim_length,
     game_flash_length,
-    game_is_solved,
+    game_status,
     TRUE, TRUE, game_print_size, game_print,
     FALSE,			       /* wants_statusbar */
     FALSE, game_timing_state,
diff --git a/midend.c b/midend.c
index 0c8b3c0..8f4e4c9 100644
--- a/midend.c
+++ b/midend.c
@@ -1336,7 +1336,7 @@ char *midend_solve(midend *me)
     return NULL;
 }
 
-int midend_is_solved(midend *me)
+int midend_status(midend *me)
 {
     /*
      * We should probably never be called when the state stack has no
@@ -1347,8 +1347,10 @@ int midend_is_solved(midend *me)
      * practically, a user whose midend has been left in that state
      * probably _does_ want the 'new game' option to be prominent.
      */
-    return (me->statepos == 0 ||
-            me->ourgame->is_solved(me->states[me->statepos-1].state));
+    if (me->statepos == 0)
+        return +1;
+
+    return me->ourgame->status(me->states[me->statepos-1].state);
 }
 
 char *midend_rewrite_statusbar(midend *me, char *text)
diff --git a/mines.c b/mines.c
index 80d2337..13cdc0c 100644
--- a/mines.c
+++ b/mines.c
@@ -3084,9 +3084,14 @@ static float game_flash_length(game_state *oldstate, game_state *newstate,
     return 0.0F;
 }
 
-static int game_is_solved(game_state *state)
+static int game_status(game_state *state)
 {
-    return state->won;
+    /*
+     * We report the game as lost only if the player has used the
+     * Solve function to reveal all the mines. Otherwise, we assume
+     * they'll undo and continue play.
+     */
+    return state->won ? (state->used_solve ? -1 : +1) : 0;
 }
 
 static int game_timing_state(game_state *state, game_ui *ui)
@@ -3139,7 +3144,7 @@ const struct game thegame = {
     game_redraw,
     game_anim_length,
     game_flash_length,
-    game_is_solved,
+    game_status,
     FALSE, FALSE, game_print_size, game_print,
     TRUE,			       /* wants_statusbar */
     TRUE, game_timing_state,
diff --git a/net.c b/net.c
index b8fd7e6..667f939 100644
--- a/net.c
+++ b/net.c
@@ -2864,9 +2864,9 @@ static float game_flash_length(game_state *oldstate,
     return 0.0F;
 }
 
-static int game_is_solved(game_state *state)
+static int game_status(game_state *state)
 {
-    return state->completed;
+    return state->completed ? +1 : 0;
 }
 
 static int game_timing_state(game_state *state, game_ui *ui)
@@ -3044,7 +3044,7 @@ const struct game thegame = {
     game_redraw,
     game_anim_length,
     game_flash_length,
-    game_is_solved,
+    game_status,
     TRUE, FALSE, game_print_size, game_print,
     TRUE,			       /* wants_statusbar */
     FALSE, game_timing_state,
diff --git a/netslide.c b/netslide.c
index 27a3934..076cad4 100644
--- a/netslide.c
+++ b/netslide.c
@@ -1826,9 +1826,9 @@ static float game_flash_length(game_state *oldstate,
     return 0.0F;
 }
 
-static int game_is_solved(game_state *state)
+static int game_status(game_state *state)
 {
-    return state->completed;
+    return state->completed ? +1 : 0;
 }
 
 static int game_timing_state(game_state *state, game_ui *ui)
@@ -1879,7 +1879,7 @@ const struct game thegame = {
     game_redraw,
     game_anim_length,
     game_flash_length,
-    game_is_solved,
+    game_status,
     FALSE, FALSE, game_print_size, game_print,
     TRUE,			       /* wants_statusbar */
     FALSE, game_timing_state,
diff --git a/nullgame.c b/nullgame.c
index 1484587..9e99109 100644
--- a/nullgame.c
+++ b/nullgame.c
@@ -238,9 +238,9 @@ static float game_flash_length(game_state *oldstate, game_state *newstate,
     return 0.0F;
 }
 
-static int game_is_solved(game_state *state)
+static int game_status(game_state *state)
 {
-    return FALSE;
+    return 0;
 }
 
 static int game_timing_state(game_state *state, game_ui *ui)
@@ -291,7 +291,7 @@ const struct game thegame = {
     game_redraw,
     game_anim_length,
     game_flash_length,
-    game_is_solved,
+    game_status,
     FALSE, FALSE, game_print_size, game_print,
     FALSE,			       /* wants_statusbar */
     FALSE, game_timing_state,
diff --git a/pattern.c b/pattern.c
index 4a72acf..043c1de 100644
--- a/pattern.c
+++ b/pattern.c
@@ -1282,9 +1282,9 @@ static float game_flash_length(game_state *oldstate,
     return 0.0F;
 }
 
-static int game_is_solved(game_state *state)
+static int game_status(game_state *state)
 {
-    return state->completed;
+    return state->completed ? +1 : 0;
 }
 
 static int game_timing_state(game_state *state, game_ui *ui)
@@ -1391,7 +1391,7 @@ const struct game thegame = {
     game_redraw,
     game_anim_length,
     game_flash_length,
-    game_is_solved,
+    game_status,
     TRUE, FALSE, game_print_size, game_print,
     FALSE,			       /* wants_statusbar */
     FALSE, game_timing_state,
diff --git a/pegs.c b/pegs.c
index 195bca1..4daa55f 100644
--- a/pegs.c
+++ b/pegs.c
@@ -1269,9 +1269,13 @@ static float game_flash_length(game_state *oldstate, game_state *newstate,
         return 0.0F;
 }
 
-static int game_is_solved(game_state *state)
+static int game_status(game_state *state)
 {
-    return state->completed;
+    /*
+     * Dead-end situations are assumed to be rescuable by Undo, so we
+     * don't bother to identify them and return -1.
+     */
+    return state->completed ? +1 : 0;
 }
 
 static int game_timing_state(game_state *state, game_ui *ui)
@@ -1322,7 +1326,7 @@ const struct game thegame = {
     game_redraw,
     game_anim_length,
     game_flash_length,
-    game_is_solved,
+    game_status,
     FALSE, FALSE, game_print_size, game_print,
     FALSE,			       /* wants_statusbar */
     FALSE, game_timing_state,
diff --git a/puzzles.h b/puzzles.h
index 1561f4a..593fd38 100644
--- a/puzzles.h
+++ b/puzzles.h
@@ -253,7 +253,7 @@ char *midend_get_game_id(midend *me);
 int midend_can_format_as_text_now(midend *me);
 char *midend_text_format(midend *me);
 char *midend_solve(midend *me);
-int midend_is_solved(midend *me);
+int midend_status(midend *me);
 int midend_can_undo(midend *me);
 int midend_can_redo(midend *me);
 void midend_supersede_game_desc(midend *me, char *desc, char *privdesc);
@@ -479,7 +479,7 @@ struct game {
 			 game_ui *ui);
     float (*flash_length)(game_state *oldstate, game_state *newstate, int dir,
 			  game_ui *ui);
-    int (*is_solved)(game_state *state);
+    int (*status)(game_state *state);
     int can_print, can_print_in_colour;
     void (*print_size)(game_params *params, float *x, float *y);
     void (*print)(drawing *dr, game_state *state, int tilesize);
diff --git a/range.c b/range.c
index 6bdba76..afb2de6 100644
--- a/range.c
+++ b/range.c
@@ -1485,9 +1485,9 @@ static float game_flash_length(game_state *from, game_state *to,
     return 0.0F;
 }
 
-static int game_is_solved(game_state *state)
+static int game_status(game_state *state)
 {
-    return state->was_solved;
+    return state->was_solved ? +1 : 0;
 }
 
 /* ----------------------------------------------------------------------
@@ -1737,7 +1737,7 @@ struct game const thegame = {
     game_redraw,
     game_anim_length,
     game_flash_length,
-    game_is_solved,
+    game_status,
     TRUE, FALSE, game_print_size, game_print,
     FALSE, /* wants_statusbar */
     FALSE, game_timing_state,
diff --git a/rect.c b/rect.c
index f9ab508..0a93638 100644
--- a/rect.c
+++ b/rect.c
@@ -2855,9 +2855,9 @@ static float game_flash_length(game_state *oldstate,
     return 0.0F;
 }
 
-static int game_is_solved(game_state *state)
+static int game_status(game_state *state)
 {
-    return state->completed;
+    return state->completed ? +1 : 0;
 }
 
 static int game_timing_state(game_state *state, game_ui *ui)
@@ -2965,7 +2965,7 @@ const struct game thegame = {
     game_redraw,
     game_anim_length,
     game_flash_length,
-    game_is_solved,
+    game_status,
     TRUE, FALSE, game_print_size, game_print,
     TRUE,			       /* wants_statusbar */
     FALSE, game_timing_state,
diff --git a/samegame.c b/samegame.c
index dc1f380..49dd64e 100644
--- a/samegame.c
+++ b/samegame.c
@@ -1611,14 +1611,13 @@ static float game_flash_length(game_state *oldstate, game_state *newstate,
 	return 0.0F;
 }
 
-static int game_is_solved(game_state *state)
+static int game_status(game_state *state)
 {
     /*
-     * If the player has run out of moves without winning, we don't
-     * list the game as solved, because they're more likely to undo
-     * and carry on than to give up and start a new game.
+     * Dead-end situations are assumed to be rescuable by Undo, so we
+     * don't bother to identify them and return -1.
      */
-    return state->complete;
+    return state->complete ? +1 : 0;
 }
 
 static int game_timing_state(game_state *state, game_ui *ui)
@@ -1669,7 +1668,7 @@ const struct game thegame = {
     game_redraw,
     game_anim_length,
     game_flash_length,
-    game_is_solved,
+    game_status,
     FALSE, FALSE, game_print_size, game_print,
     TRUE,			       /* wants_statusbar */
     FALSE, game_timing_state,
diff --git a/signpost.c b/signpost.c
index fdeadba..3f2a645 100644
--- a/signpost.c
+++ b/signpost.c
@@ -2122,9 +2122,9 @@ static float game_flash_length(game_state *oldstate, game_state *newstate,
         return 0.0F;
 }
 
-static int game_is_solved(game_state *state)
+static int game_status(game_state *state)
 {
-    return state->completed;
+    return state->completed ? +1 : 0;
 }
 
 static int game_timing_state(game_state *state, game_ui *ui)
@@ -2208,7 +2208,7 @@ const struct game thegame = {
     game_redraw,
     game_anim_length,
     game_flash_length,
-    game_is_solved,
+    game_status,
     TRUE, FALSE, game_print_size, game_print,
     FALSE,			       /* wants_statusbar */
     FALSE, game_timing_state,
diff --git a/singles.c b/singles.c
index 2c33337..ff75cfb 100644
--- a/singles.c
+++ b/singles.c
@@ -1735,9 +1735,9 @@ static float game_flash_length(game_state *oldstate, game_state *newstate,
     return 0.0F;
 }
 
-static int game_is_solved(game_state *state)
+static int game_status(game_state *state)
 {
-    return state->completed;
+    return state->completed ? +1 : 0;
 }
 
 static int game_timing_state(game_state *state, game_ui *ui)
@@ -1826,7 +1826,7 @@ const struct game thegame = {
     game_redraw,
     game_anim_length,
     game_flash_length,
-    game_is_solved,
+    game_status,
     TRUE, FALSE, game_print_size, game_print,
     FALSE,			       /* wants_statusbar */
     FALSE, game_timing_state,
diff --git a/sixteen.c b/sixteen.c
index 6f061cd..8079fac 100644
--- a/sixteen.c
+++ b/sixteen.c
@@ -1073,9 +1073,9 @@ static float game_flash_length(game_state *oldstate,
         return 0.0F;
 }
 
-static int game_is_solved(game_state *state)
+static int game_status(game_state *state)
 {
-    return state->completed;
+    return state->completed ? +1 : 0;
 }
 
 static int game_timing_state(game_state *state, game_ui *ui)
@@ -1126,7 +1126,7 @@ const struct game thegame = {
     game_redraw,
     game_anim_length,
     game_flash_length,
-    game_is_solved,
+    game_status,
     FALSE, FALSE, game_print_size, game_print,
     TRUE,			       /* wants_statusbar */
     FALSE, game_timing_state,
diff --git a/slant.c b/slant.c
index f85644c..52f21d6 100644
--- a/slant.c
+++ b/slant.c
@@ -2079,9 +2079,9 @@ static float game_flash_length(game_state *oldstate, game_state *newstate,
     return 0.0F;
 }
 
-static int game_is_solved(game_state *state)
+static int game_status(game_state *state)
 {
-    return state->completed;
+    return state->completed ? +1 : 0;
 }
 
 static int game_timing_state(game_state *state, game_ui *ui)
@@ -2195,7 +2195,7 @@ const struct game thegame = {
     game_redraw,
     game_anim_length,
     game_flash_length,
-    game_is_solved,
+    game_status,
     TRUE, FALSE, game_print_size, game_print,
     FALSE,			       /* wants_statusbar */
     FALSE, game_timing_state,
diff --git a/solo.c b/solo.c
index 8e50c3b..052ebef 100644
--- a/solo.c
+++ b/solo.c
@@ -5187,9 +5187,9 @@ static float game_flash_length(game_state *oldstate, game_state *newstate,
     return 0.0F;
 }
 
-static int game_is_solved(game_state *state)
+static int game_status(game_state *state)
 {
-    return state->completed;
+    return state->completed ? +1 : 0;
 }
 
 static int game_timing_state(game_state *state, game_ui *ui)
@@ -5511,7 +5511,7 @@ const struct game thegame = {
     game_redraw,
     game_anim_length,
     game_flash_length,
-    game_is_solved,
+    game_status,
     TRUE, FALSE, game_print_size, game_print,
     FALSE,			       /* wants_statusbar */
     FALSE, game_timing_state,
diff --git a/tents.c b/tents.c
index 6cf406d..cfdcdc3 100644
--- a/tents.c
+++ b/tents.c
@@ -2522,9 +2522,9 @@ static float game_flash_length(game_state *oldstate, game_state *newstate,
     return 0.0F;
 }
 
-static int game_is_solved(game_state *state)
+static int game_status(game_state *state)
 {
-    return state->completed;
+    return state->completed ? +1 : 0;
 }
 
 static int game_timing_state(game_state *state, game_ui *ui)
@@ -2597,7 +2597,7 @@ const struct game thegame = {
     game_redraw,
     game_anim_length,
     game_flash_length,
-    game_is_solved,
+    game_status,
     TRUE, FALSE, game_print_size, game_print,
     FALSE,			       /* wants_statusbar */
     FALSE, game_timing_state,
diff --git a/towers.c b/towers.c
index 94ed1a7..be0a730 100644
--- a/towers.c
+++ b/towers.c
@@ -1808,9 +1808,9 @@ static float game_flash_length(game_state *oldstate, game_state *newstate,
     return 0.0F;
 }
 
-static int game_is_solved(game_state *state)
+static int game_status(game_state *state)
 {
-    return state->completed;
+    return state->completed ? +1 : 0;
 }
 
 static int game_timing_state(game_state *state, game_ui *ui)
@@ -1932,7 +1932,7 @@ const struct game thegame = {
     game_redraw,
     game_anim_length,
     game_flash_length,
-    game_is_solved,
+    game_status,
     TRUE, FALSE, game_print_size, game_print,
     FALSE,			       /* wants_statusbar */
     FALSE, game_timing_state,
diff --git a/twiddle.c b/twiddle.c
index c5f89f8..51a21f0 100644
--- a/twiddle.c
+++ b/twiddle.c
@@ -1069,9 +1069,9 @@ static float game_flash_length(game_state *oldstate, game_state *newstate,
         return 0.0F;
 }
 
-static int game_is_solved(game_state *state)
+static int game_status(game_state *state)
 {
-    return state->completed;
+    return state->completed ? +1 : 0;
 }
 
 static void game_redraw(drawing *dr, game_drawstate *ds, game_state *oldstate,
@@ -1291,7 +1291,7 @@ const struct game thegame = {
     game_redraw,
     game_anim_length,
     game_flash_length,
-    game_is_solved,
+    game_status,
     FALSE, FALSE, game_print_size, game_print,
     TRUE,			       /* wants_statusbar */
     FALSE, game_timing_state,
diff --git a/unequal.c b/unequal.c
index 29f0527..5dcca36 100644
--- a/unequal.c
+++ b/unequal.c
@@ -1865,9 +1865,9 @@ static float game_flash_length(game_state *oldstate, game_state *newstate,
     return 0.0F;
 }
 
-static int game_is_solved(game_state *state)
+static int game_status(game_state *state)
 {
-    return state->completed;
+    return state->completed ? +1 : 0;
 }
 
 static int game_timing_state(game_state *state, game_ui *ui)
@@ -1958,7 +1958,7 @@ const struct game thegame = {
     game_redraw,
     game_anim_length,
     game_flash_length,
-    game_is_solved,
+    game_status,
     TRUE, FALSE, game_print_size, game_print,
     FALSE,			       /* wants_statusbar */
     FALSE, game_timing_state,
diff --git a/unfinished/group.c b/unfinished/group.c
index 869ff04..79bd3fa 100644
--- a/unfinished/group.c
+++ b/unfinished/group.c
@@ -1813,9 +1813,9 @@ static float game_flash_length(game_state *oldstate, game_state *newstate,
     return 0.0F;
 }
 
-static int game_is_solved(game_state *state)
+static int game_status(game_state *state)
 {
-    return state->completed;
+    return state->completed ? +1 : 0;
 }
 
 static int game_timing_state(game_state *state, game_ui *ui)
@@ -1936,7 +1936,7 @@ const struct game thegame = {
     game_redraw,
     game_anim_length,
     game_flash_length,
-    game_is_solved,
+    game_status,
     TRUE, FALSE, game_print_size, game_print,
     FALSE,			       /* wants_statusbar */
     FALSE, game_timing_state,
diff --git a/unfinished/pearl.c b/unfinished/pearl.c
index 843d99e..51b2ed2 100644
--- a/unfinished/pearl.c
+++ b/unfinished/pearl.c
@@ -1349,9 +1349,9 @@ static float game_flash_length(game_state *oldstate, game_state *newstate,
     return 0.0F;
 }
 
-static int game_is_solved(game_state *state)
+static int game_status(game_state *state)
 {
-    return FALSE;
+    return 0;
 }
 
 static int game_timing_state(game_state *state, game_ui *ui)
@@ -1402,7 +1402,7 @@ const struct game thegame = {
     game_redraw,
     game_anim_length,
     game_flash_length,
-    game_is_solved,
+    game_status,
     FALSE, FALSE, game_print_size, game_print,
     FALSE,			       /* wants_statusbar */
     FALSE, game_timing_state,
diff --git a/unfinished/separate.c b/unfinished/separate.c
index b11f604..b20cb52 100644
--- a/unfinished/separate.c
+++ b/unfinished/separate.c
@@ -795,9 +795,9 @@ static float game_flash_length(game_state *oldstate, game_state *newstate,
     return 0.0F;
 }
 
-static int game_is_solved(game_state *state)
+static int game_status(game_state *state)
 {
-    return FALSE;
+    return 0;
 }
 
 static int game_timing_state(game_state *state, game_ui *ui)
@@ -848,7 +848,7 @@ const struct game thegame = {
     game_redraw,
     game_anim_length,
     game_flash_length,
-    game_is_solved,
+    game_status,
     FALSE, FALSE, game_print_size, game_print,
     FALSE,			       /* wants_statusbar */
     FALSE, game_timing_state,
diff --git a/unfinished/slide.c b/unfinished/slide.c
index fbaa630..6fac469 100644
--- a/unfinished/slide.c
+++ b/unfinished/slide.c
@@ -2292,9 +2292,9 @@ static float game_flash_length(game_state *oldstate, game_state *newstate,
     return 0.0F;
 }
 
-static int game_is_solved(game_state *state)
+static int game_status(game_state *state)
 {
-    return state->completed;
+    return state->completed ? +1 : 0;
 }
 
 static int game_timing_state(game_state *state, game_ui *ui)
@@ -2345,7 +2345,7 @@ const struct game thegame = {
     game_redraw,
     game_anim_length,
     game_flash_length,
-    game_is_solved,
+    game_status,
     FALSE, FALSE, game_print_size, game_print,
     TRUE,			       /* wants_statusbar */
     FALSE, game_timing_state,
diff --git a/unfinished/sokoban.c b/unfinished/sokoban.c
index b389eb5..53bd3a5 100644
--- a/unfinished/sokoban.c
+++ b/unfinished/sokoban.c
@@ -1415,9 +1415,9 @@ static float game_flash_length(game_state *oldstate, game_state *newstate,
         return 0.0F;
 }
 
-static int game_is_solved(game_state *state)
+static int game_status(game_state *state)
 {
-    return state->completed;
+    return state->completed ? +1 : 0;
 }
 
 static int game_timing_state(game_state *state, game_ui *ui)
@@ -1468,7 +1468,7 @@ const struct game thegame = {
     game_redraw,
     game_anim_length,
     game_flash_length,
-    game_is_solved,
+    game_status,
     FALSE, FALSE, game_print_size, game_print,
     FALSE,			       /* wants_statusbar */
     FALSE, game_timing_state,
diff --git a/untangle.c b/untangle.c
index 7a34475..c07c957 100644
--- a/untangle.c
+++ b/untangle.c
@@ -1412,9 +1412,9 @@ static float game_flash_length(game_state *oldstate, game_state *newstate,
     return 0.0F;
 }
 
-static int game_is_solved(game_state *state)
+static int game_status(game_state *state)
 {
-    return state->completed;
+    return state->completed ? +1 : 0;
 }
 
 static int game_timing_state(game_state *state, game_ui *ui)
@@ -1465,7 +1465,7 @@ const struct game thegame = {
     game_redraw,
     game_anim_length,
     game_flash_length,
-    game_is_solved,
+    game_status,
     FALSE, FALSE, game_print_size, game_print,
     FALSE,			       /* wants_statusbar */
     FALSE, game_timing_state,
-- 
2.11.0