added `P` command as a reverse form of `W`

* All the movement commands have shortcuts for their negative forms:
  `R` instead of `-C`, `B` instead of `-L`.
  Therefore there was always the need for a `-W` shortcut as well.
* `P` is a good choice because it is a file IO command in TECO-11,
  that does not make sense supporting.
  In Video TECO it toggles between display windows (ie. split screens)
  and I do not plan to support multiple windows in SciTECO.
* Added to the cheat sheet.

5 files changed, 49 insertions, 9 deletions

diff --git a/doc/cheat-sheet.mm b/doc/cheat-sheet.mm
index ab404e3..60104ff 100644
--- a/doc/cheat-sheet.mm
+++ b/doc/cheat-sheet.mm
@@ -419,12 +419,12 @@ Read \fIfile\fP into Q-Register \fIq\fP.
 .    TD
 .      CI C
 .    TD
-Move one character forward.
+Move to next character.
 .  TRX
 .    TD
 .      CI "" n C
 .    TD
-Move \fIn\fP characters forward.
+Move \fIn\fP characters forwards.
 .  TRX
 .    TD
 .      CI R
@@ -439,17 +439,24 @@ Move \fIn\fP characters backwards (reverse).
 .    TD
 .      CI W
 .    TD
-Move to the beginning of next word.
+Move to next word.
+.  TRX
+.    TD
+.      CI P
+.    TD
+Move to previous word.
 .  TRX
 .    TD
 .      CI L
 .    TD
 Move to the beginning of next line.
+.ig END
 .  TRX
 .    TD
 .      CI "" n L
 .    TD
 Move forward \fIn\fP lines.
+.END
 .  TRX
 .    TD
 .      CI 0L
diff --git a/src/core-commands.c b/src/core-commands.c
index f39f6f9..4abf38b 100644
--- a/src/core-commands.c
+++ b/src/core-commands.c
@@ -659,7 +659,8 @@ teco_state_start_input(teco_machine_main_t *ctx, gunichar chr, GError **error)
 		['R']  = {&teco_state_start, teco_state_start_reverse},
 		['L']  = {&teco_state_start, teco_state_start_line},
 		['B']  = {&teco_state_start, teco_state_start_back},
-		['W']  = {&teco_state_start, teco_state_start_word},
+		['W']  = {&teco_state_start, teco_state_start_words},
+		['P']  = {&teco_state_start, teco_state_start_words_back},
 		['V']  = {&teco_state_start, teco_state_start_delete_words},
 		['Y']  = {&teco_state_start, teco_state_start_delete_words_back},
 		['=']  = {&teco_state_start, teco_state_start_print},
diff --git a/src/move-commands.c b/src/move-commands.c
index 8abd8ca..5339f24 100644
--- a/src/move-commands.c
+++ b/src/move-commands.c
@@ -316,7 +316,7 @@ teco_find_words(gsize *pos, teco_int_t n)
 }
 
 /*$ W word
- * [n]W -- Move dot by words
+ * [n]W -- Move dot <n> words forwards
  * -W
  * [n]:W -> Success|Failure
  *
@@ -337,7 +337,7 @@ teco_find_words(gsize *pos, teco_int_t n)
  * If colon-modified it instead returns a condition code.
  */
 void
-teco_state_start_word(teco_machine_main_t *ctx, GError **error)
+teco_state_start_words(teco_machine_main_t *ctx, GError **error)
 {
 	teco_int_t v;
 	if (!teco_expressions_pop_num_calc(&v, teco_num_sign, error))
@@ -360,6 +360,38 @@ teco_state_start_word(teco_machine_main_t *ctx, GError **error)
 		teco_expressions_push(TECO_SUCCESS);
 }
 
+/*$ P
+ * [n]P -- Move dot <n> words backwards
+ * -P
+ * [n]:P -> Success|Failure
+ *
+ * Move dot to the beginning of preceding words.
+ * It is equivalent to \(lq-nW\(rq.
+ */
+void
+teco_state_start_words_back(teco_machine_main_t *ctx, GError **error)
+{
+	teco_int_t v;
+	if (!teco_expressions_pop_num_calc(&v, teco_num_sign, error))
+		return;
+	sptr_t pos = teco_interface_ssm(SCI_GETCURRENTPOS, 0, 0);
+
+	gsize word_pos = pos;
+	if (!teco_find_words(&word_pos, -v)) {
+		if (!teco_machine_main_eval_colon(ctx))
+			teco_error_move_set(error, "P");
+		else
+			teco_expressions_push(TECO_FAILURE);
+		return;
+	}
+
+	if (teco_current_doc_must_undo())
+		undo__teco_interface_ssm(SCI_GOTOPOS, pos, 0);
+	teco_interface_ssm(SCI_GOTOPOS, word_pos, 0);
+	if (teco_machine_main_eval_colon(ctx) > 0)
+		teco_expressions_push(TECO_SUCCESS);
+}
+
 static gboolean
 teco_delete_words(teco_int_t n)
 {
diff --git a/src/move-commands.h b/src/move-commands.h
index 36acec8..9dddc8d 100644
--- a/src/move-commands.h
+++ b/src/move-commands.h
@@ -28,7 +28,8 @@ void teco_state_start_reverse(teco_machine_main_t *ctx, GError **error);
 void teco_state_start_line(teco_machine_main_t *ctx, GError **error);
 void teco_state_start_back(teco_machine_main_t *ctx, GError **error);
 
-void teco_state_start_word(teco_machine_main_t *ctx, GError **error);
+void teco_state_start_words(teco_machine_main_t *ctx, GError **error);
+void teco_state_start_words_back(teco_machine_main_t *ctx, GError **error);
 
 void teco_state_start_delete_words(teco_machine_main_t *ctx, GError **error);
 void teco_state_start_delete_words_back(teco_machine_main_t *ctx, GError **error);
diff --git a/tests/testsuite.at b/tests/testsuite.at
index c76c4c5..7c3cf97 100644
--- a/tests/testsuite.at
+++ b/tests/testsuite.at
@@ -116,8 +116,7 @@ AT_CLEANUP
 AT_SETUP([Moving by words])
 AT_CHECK([$SCITECO -e "Z= 3J 2W .-18\"N(0/0)'" "$WORDS_EXAMPLE"], 0, ignore, ignore)
 AT_CHECK([$SCITECO -e "@I/foo ^J bar/ JW .-6\"N(0/0)'"], 0, ignore, ignore)
-# FIXME: Sooner or later, there will be a shortcut for -W.
-AT_CHECK([$SCITECO -e "Z-4J -3W .-12\"N(0/0)'" "$WORDS_EXAMPLE"], 0, ignore, ignore)
+AT_CHECK([$SCITECO -e "Z-4J 3P .-12\"N(0/0)'" "$WORDS_EXAMPLE"], 0, ignore, ignore)
 AT_CLEANUP
 
 AT_SETUP([Deleting words])