Add support for more keyboard shortcuts (#410)

Add extra key bindings to the emacs and vi modes

This patch adds the following key bindings to the emacs and vi
editing modes:
- Support for Home key sequences ^[[1~ and ^[[7~ as well as End key
  sequences ^[[4~ and ^[[8~.
- Support for arrow key sequences ^[OA, ^[OB, ^[OC and ^[OD.
- Support for the following keyboard shortcuts (if the platform
  supports the expected escape sequence):
  - Ctrl-Left Arrow:  Go back one word
  - Alt-Left Arrow:   Go back one word     (Not supported on Haiku)
  - Ctrl-Right Arrow: Go forward one word
  - Alt-Right Arrow:  Go forward one word  (Not supported on Haiku)
  - Ctrl-G:           Cancel reverse search
  - Ctrl-Delete:      Delete next word     (Not supported on Haiku)
- Added a key binding for the Insert key, which differs in the
  emacs and vi editing modes:
  - In emacs mode, Insert escapes the next character.
  - In vi mode, Insert will switch the editor to insert mode (like
    in vim).

src/cmd/ksh93/edit/{emacs,vi}.c:
- Add support for the <M-Left> and <M-Right> sequences. Like in
  bash and mksh, these shortcuts move the cursor one word backward
  or forward (like the <Ctrl-Left> and <Ctrl-Right> shortcuts).
- Only attempt to process these shortcuts if the escape sequence
  begins with $'\E[1;'.

src/cmd/ksh93/edit/vi.c:
- If the shell isn't doing a reverse search, insert the bell
  character when Ctrl+G is input.
- Add the Ctrl-Delete shortcut as an alias of 'dw'. Calling
  ed_ungetchar twice does not work for 'dw', so Ctrl-Delete was
  implemented by using a vp->del_word variable.

Co-authored-by: Martijn Dekker <martijn@inlv.org>

ANNOUNCE

@@ -56,6 +56,15 @@ New features in built-in commands:
   Note that to use these options the operating system must support the
   corresponding resource limit.
 
+New command line editor features:
+
+- Various keys on extended PC keyboards are now handled as expected in the
+  emacs and vi built-in line editors: Ctrl or Alt + left or right arrow (go
+  back or forward one word), Ctrl+G (cancel reverse search), Ctrl+Delete
+  (delete next word). In addition, the Insert key now escapes the next
+  character in emacs and enters insert mode in vi, and the arrow keys are
+  recognized on more terminals.
+
 New features in shell options:
 
 - The new --histreedit and --histverify options modify history expansion

NEWS

@@ -3,6 +3,25 @@ For full details, see the git log at: https://github.com/ksh93/ksh/tree/1.0
 
 Any uppercase BUG_* names are modernish shell bug IDs.
 
+2022-01-31:
+
+- Improved keyboard support for the vi and emacs built-in line editors:
+  - Added support for Home key sequences ^[[1~ and ^[[7~ as well as End key
+    sequences ^[[4~ and ^[[8~.
+  - Added support for arrow key sequences ^[OA, ^[OB, ^[OC and ^[OD.
+  - Added support for the following keyboard shortcuts (if the platform
+    supports the expected escape sequence):
+    - Ctrl-Left Arrow:  Go back one word
+    - Alt-Left Arrow:   Go back one word        (Not supported on Haiku)
+    - Ctrl-Right Arrow: Go forward one word
+    - Alt-Right Arrow:  Go forward one word     (Not supported on Haiku)
+    - Ctrl-G:           Cancel reverse search
+    - Ctrl-Delete:      Delete next word        (Not supported on Haiku)
+  - Added a keybind for the Insert key, which differs in the emacs and vi
+    editing modes:
+    - In emacs mode, Insert escapes the next character.
+    - In vi mode, Insert will switch the editor to insert mode (like in vim).
+
 2022-01-28:
 
 - Fixed longstanding job control breakage that occurred on the interactive

src/cmd/ksh93/edit/emacs.c

@@ -780,7 +780,7 @@ static void putstring(Emacs_t* ep,register char *sp)
 static int escape(register Emacs_t* ep,register genchar *out,int count)
 {
 	register int i,value;
-	int digit,ch;
+	int digit,ch,c,d;
 	digit = 0;
 	value = 0;
 	while ((i=ed_getchar(ep->ed,0)),digit(i))
@@ -827,6 +827,7 @@ static int escape(register Emacs_t* ep,register genchar *out,int count)
 		case 'd':	/* M-d == delete word */
 		case 'c':	/* M-c == uppercase */
 		case 'f':	/* M-f == move cursor forward one word */
+		forward:
 		{
 			i = cur;
 			while(value-- && i<eol)
@@ -883,6 +884,7 @@ static int escape(register Emacs_t* ep,register genchar *out,int count)
 		case DELETE :
 		case '\b':
 		case 'h':	/* M-h == delete the previous word */
+		backward:
 		{
 			i = cur;
 			while(value-- && i>0)
@@ -1079,6 +1081,7 @@ static int escape(register Emacs_t* ep,register genchar *out,int count)
 			return(-1);
 #endif
 		case '[':	/* feature not in book */
+		case 'O':	/* after running top <ESC>O instead of <ESC>[ */
 			switch(i=ed_getchar(ep->ed,1))
 			{
 			    case 'A':
@@ -1131,8 +1134,53 @@ static int escape(register Emacs_t* ep,register genchar *out,int count)
 				/* VT220 End key */
 				ed_ungetchar(ep->ed,cntl('E'));
 				return(-1);
+			    case '1':
+			    case '7':
+				/*
+				 * ed_getchar() can only be run once on each character
+				 * and shouldn't be used on non-existent characters.
+				 */
+				ch = ed_getchar(ep->ed,1);
+				if(ch == '~')
+				{ /* Home key */
+					ed_ungetchar(ep->ed,cntl('A'));
+					return(-1);
+				}
+				else if(i == '1' && ch == ';')
+				{
+					c = ed_getchar(ep->ed,1);
+					if(c == '3' || c == '5' || c == '9') /* 3 == Alt, 5 == Ctrl, 9 == iTerm2 Alt */
+					{
+						d = ed_getchar(ep->ed,1);
+						switch(d)
+						{
+						    case 'D': /* Ctrl/Alt-Left arrow (go back one word) */
+							ch = 'b';
+							goto backward;
+						    case 'C': /* Ctrl/Alt-Right arrow (go forward one word) */
+							ch = 'f';
+							goto forward;
+						}
+						ed_ungetchar(ep->ed,d);
+					}
+					ed_ungetchar(ep->ed,c);
+				}
+				ed_ungetchar(ep->ed,ch);
+				ed_ungetchar(ep->ed,i);
+				return(-1);
+			    case '2': /* Insert key */
+				ch = ed_getchar(ep->ed,1);
+				if(ch == '~')
+				{
+					ed_ungetchar(ep->ed, cntl('V'));
+					return(-1);
+				}
+				ed_ungetchar(ep->ed,ch);
+				ed_ungetchar(ep->ed,i);
+				return(-1);
 			    case '3':
-				if((ch=ed_getchar(ep->ed,1))=='~')
+				ch = ed_getchar(ep->ed,1);
+				if(ch == '~')
 				{	/*
 					 * VT220 forward-delete key.
 					 * Since ERASECHAR and EOFCHAR are usually both mapped to ^D, we
@@ -1143,6 +1191,47 @@ static int escape(register Emacs_t* ep,register genchar *out,int count)
 						ed_ungetchar(ep->ed,ERASECHAR);
 					return(-1);
 				}
+				else if(ch == ';')
+				{
+					c = ed_getchar(ep->ed,1);
+					if(c == '5')
+					{
+						d = ed_getchar(ep->ed,1);
+						if(d == '~')
+						{
+							/* Ctrl-Delete (delete next word) */
+							ch = 'd';
+							goto forward;
+						}
+						ed_ungetchar(ep->ed,d);
+					}
+					ed_ungetchar(ep->ed,c);
+				}
+				ed_ungetchar(ep->ed,ch);
+				ed_ungetchar(ep->ed,i);
+				return(-1);
+			    case '5':  /* Haiku terminal Ctrl-Arrow key */
+				ch = ed_getchar(ep->ed,1);
+				switch(ch)
+				{
+				    case 'D': /* Ctrl-Left arrow (go back one word) */
+					ch = 'b';
+					goto backward;
+				    case 'C': /* Ctrl-Right arrow (go forward one word) */
+					ch = 'f';
+					goto forward;
+				}
+				ed_ungetchar(ep->ed,ch);
+				ed_ungetchar(ep->ed,i);
+				return(-1);
+			    case '4':
+			    case '8': /* rxvt */
+				ch = ed_getchar(ep->ed,1);
+				if(ch == '~')
+				{
+					ed_ungetchar(ep->ed,cntl('E')); /* End key */
+					return(-1);
+				}
 				ed_ungetchar(ep->ed,ch);
 				/* FALLTHROUGH */
 			    default:
@@ -1288,7 +1377,7 @@ static void search(Emacs_t* ep,genchar *out,int direction)
 				goto restore;
 			continue;
 		}
-		if(i == ep->ed->e_intr)  /* end reverse search */
+		if(i == ep->ed->e_intr || i == cntl('G'))  /* end reverse search */
 			goto restore;
 		if (i==usrkill)
 		{

src/cmd/ksh93/edit/vi.c

@@ -112,6 +112,7 @@ typedef struct _vi_
 	int U_saved;		/* original virtual saved */
 	genchar *U_space;	/* used for U command */
 	genchar *u_space;	/* used for u command */
+	unsigned char del_word;	/* used for Ctrl-Delete */
 #ifdef FIORDCHK
 	clock_t typeahead;	/* typeahead occurred */
 #else
@@ -753,7 +754,7 @@ static int cntlmode(Vi_t *vp)
 		if(mvcursor(vp,c))
 		{
 			sync_cursor(vp);
-			if( c != '[' )
+			if( c != '[' && c != 'O' )
 				vp->repeat = 1;
 			continue;
 		}
@@ -1036,7 +1037,7 @@ static int cntlmode(Vi_t *vp)
 			if(lookahead)
 			{
 				ed_ungetchar(vp->ed,c=ed_getchar(vp->ed,1));
-				if(c=='[')
+				if(c=='[' || c=='O')
 					continue;
 			}
 			/* FALLTHROUGH */
@@ -1430,6 +1431,10 @@ static void getline(register Vi_t* vp,register int mode)
 			}
 			break;
 
+		case cntl('G'):
+			if(mode!=SEARCH)
+				goto fallback;
+			/* FALLTHROUGH */
 		case UINTR:
 				first_virt = 0;
 				cdelete(vp,cur_virt+1, BAD);
@@ -1550,6 +1555,7 @@ static void getline(register Vi_t* vp,register int mode)
 			}
 			/* FALLTHROUGH */
 		default:
+		fallback:
 			if( mode == REPLACE )
 			{
 				if( cur_virt < last_virt )
@@ -1583,7 +1589,7 @@ static void getline(register Vi_t* vp,register int mode)
 
 static int mvcursor(register Vi_t* vp,register int motion)
 {
-	register int count;
+	register int count, c, d;
 	register int tcur_virt;
 	register int incr = -1;
 	register int bound = 0;
@@ -1612,7 +1618,8 @@ static int mvcursor(register Vi_t* vp,register int motion)
 		tcur_virt = last_virt;
 		break;
 
-	case '[':
+	case '[':	/* feature not in book */
+	case 'O':	/* after running top <ESC>O instead of <ESC>[ */
 		switch(motion=ed_getchar(vp->ed,-1))
 		{
 		    case 'A':
@@ -1659,6 +1666,47 @@ static int mvcursor(register Vi_t* vp,register int motion)
 			/* VT220 End key */
 			ed_ungetchar(vp->ed,'$');
 			return(1);
+		    case '1':
+		    case '7':
+			bound = ed_getchar(vp->ed,-1);
+			if(bound=='~')
+			{ /* Home key */
+				ed_ungetchar(vp->ed,'0');
+				return(1);
+			}
+			else if(motion=='1' && bound==';')
+			{
+				c = ed_getchar(vp->ed,-1);
+				if(c == '3' || c == '5' || c == '9') /* 3 == Alt, 5 == Ctrl, 9 == iTerm2 Alt */
+				{
+					d = ed_getchar(vp->ed,-1);
+					switch(d)
+					{
+					    case 'D': /* Ctrl/Alt-Left arrow (go back one word) */
+						ed_ungetchar(vp->ed, 'b');
+						return(1);
+					    case 'C': /* Ctrl/Alt-Right arrow (go forward one word) */
+						ed_ungetchar(vp->ed, 'w');
+						return(1);
+					}
+					ed_ungetchar(vp->ed,d);
+				}
+				ed_ungetchar(vp->ed,c);
+			}
+			ed_ungetchar(vp->ed,bound);
+			ed_ungetchar(vp->ed,motion);
+			return(0);
+		    case '2':
+			bound = ed_getchar(vp->ed,-1);
+			if(bound=='~')
+			{
+				/* VT220 insert key */
+				ed_ungetchar(vp->ed,'i');
+				return(1);
+			}
+			ed_ungetchar(vp->ed,bound);
+			ed_ungetchar(vp->ed,motion);
+			return(0);
 		    case '3':
 			bound = ed_getchar(vp->ed,-1);
 			if(bound=='~')
@@ -1667,6 +1715,48 @@ static int mvcursor(register Vi_t* vp,register int motion)
 				ed_ungetchar(vp->ed,'x');
 				return(1);
 			}
+			else if(bound==';')
+			{
+				c = ed_getchar(vp->ed,-1);
+				if(c == '5')
+				{
+					d = ed_getchar(vp->ed,-1);
+					if(d == '~')
+					{
+						/* Ctrl-Delete */
+						vp->del_word = 1;
+						ed_ungetchar(vp->ed,'d');
+						return(1);
+					}
+					ed_ungetchar(vp->ed,d);
+				}
+				ed_ungetchar(vp->ed,c);
+			}
+			ed_ungetchar(vp->ed,bound);
+			ed_ungetchar(vp->ed,motion);
+			return(0);
+		    case '5':  /* Haiku terminal Ctrl-Arrow key */
+			bound = ed_getchar(vp->ed,-1);
+			switch(bound)
+			{
+			    case 'D': /* Ctrl-Left arrow (go back one word) */
+				ed_ungetchar(vp->ed, 'b');
+				return(1);
+			    case 'C': /* Ctrl-Right arrow (go forward one word) */
+				ed_ungetchar(vp->ed, 'w');
+				return(1);
+			}
+			ed_ungetchar(vp->ed,bound);
+			ed_ungetchar(vp->ed,motion);
+			return(0);
+		    case '4':
+		    case '8':
+			bound = ed_getchar(vp->ed,-1);
+			if(bound=='~')
+			{ /* End key */
+				ed_ungetchar(vp->ed,'$');
+				return(1);
+			}
 			ed_ungetchar(vp->ed,bound);
 			/* FALLTHROUGH */
 		    default:
@@ -2602,6 +2692,11 @@ chgeol:
 	case 'd':		/** delete **/
 		if( mode )
 			c = vp->lastmotion;
+		else if( vp->del_word )
+		{
+			vp->del_word = 0;
+			c = 'w';
+		}
 		else
 			c = getcount(vp,ed_getchar(vp->ed,-1));
 deleol:

src/cmd/ksh93/include/version.h

@@ -21,7 +21,7 @@
 
 #define SH_RELEASE_FORK	"93u+m"		/* only change if you develop a new ksh93 fork */
 #define SH_RELEASE_SVER	"1.0.0-beta.2"	/* semantic version number: https://semver.org */
-#define SH_RELEASE_DATE	"2022-01-28"	/* must be in this format for $((.sh.version)) */
+#define SH_RELEASE_DATE	"2022-01-31"	/* must be in this format for $((.sh.version)) */
 #define SH_RELEASE_CPYR	"(c) 2020-2022 Contributors to ksh " SH_RELEASE_FORK
 
 /* Scripts sometimes field-split ${.sh.version}, so don't change amount of whitespace. */

src/cmd/ksh93/sh.1

@@ -4922,6 +4922,15 @@ Move cursor forward one word.
 editor's idea of a word is a string of characters
 consisting of only letters, digits and underscores.)
 .TP 10
+.BI M-[1;3C
+(Alt-Right arrow) Same as \fBM-f\fR.
+.TP 10
+.BI M-[1;5C
+(Ctrl-Right arrow) Same as \fBM-f\fR.
+.TP 10
+.BI M-[1;9C
+(iTerm2 Alt-Right arrow) Same as \fBM-f\fR.
+.TP 10
 .BI ^B
 Move cursor backward (left) one character.
 .TP 10
@@ -4931,21 +4940,60 @@ Move cursor backward (left) one character.
 .BI M-b
 Move cursor backward one word.
 .TP 10
+.BI M-[1;3D
+(Alt-Left arrow) Same as \fBM-b\fR.
+.TP 10
+.BI M-[1;5D
+(Ctrl-Left arrow) Same as \fBM-b\fR.
+.TP 10
+.BI M-[1;9D
+(iTerm2 Alt-Left arrow) Same as \fBM-b\fR.
+.TP 10
 .BI ^A
 Move cursor to start of line.
 .TP 10
 .BI M-[H
 (Home) Same as \fB^A\fR.
 .TP 10
+.BI M-[1~
+Same as \fB^A\fR.
+.TP 10
+.BI M-[7~
+Same as \fB^A\fR.
+.TP 10
 .BI ^E
 Move cursor to end of line.
 .TP 10
 .BI M-[F
 (End) Same as \fB^E\fR.
 .TP 10
+.BI M-[4~
+Same as \fB^E\fR.
+.TP 10
+.BI M-[8~
+Same as \fB^E\fR.
+.TP 10
 .BI M-[Y
 Same as \fB^E\fR.
 .TP 10
+.BI M-OA
+(Up Arrow) Same as \fBM-[A\fR.
+.TP 10
+.BI M-OB
+(Down Arrow) Same as \fBM-[B\fR.
+.TP 10
+.BI M-OC
+(Right Arrow) Same as \fBM-[C\fR.
+.TP 10
+.BI M-OD
+(Left Arrow) Same as \fBM-[D\fR.
+.TP 10
+.BI M-O5C
+(Ctrl-Right Arrow) Same as \fBM-f\fR.
+.TP 10
+.BI M-O5D
+(Ctrl-Left Arrow) Same as \fBM-b\fR.
+.TP 10
 .BI ^] char
 Move cursor forward to character
 .I char
@@ -4987,6 +5035,9 @@ Delete current character.
 .BI M-d
 Delete current word.
 .TP 10
+.BI M-[3;5~
+(Ctrl-Delete) Same as \fBM-d\fR.
+.TP 10
 .BI M-^H
 (Meta-backspace) Delete previous word.
 .TP 10
@@ -5130,6 +5181,9 @@ is accessed.
 In this case a parameter of zero
 reverses the direction of the search.
 .TP 10
+.B ^G
+Exit reverse search mode.
+.TP 10
 .B ^O
 Operate \- Execute the current line and fetch
 the next line relative to current line from the
@@ -5247,6 +5301,9 @@ which is not subject to any shell option.
 .B M-^V
 Display version of the shell.
 .TP 10
+.BI M-[2~
+(Insert) Escape the next character.
+.TP 10
 .B M-#
 If the line does not begin with a
 .BR # ,
@@ -5437,6 +5494,54 @@ Cursor to start of line.
 .B ^[[H
 (Home) Same as \f30\fP.
 .TP 10
+.B ^[[1~
+Same as \f30\fP.
+.TP 10
+.B ^[[7~
+Same as \f30\fP.
+.TP 10
+.B ^[[1;3D
+(Alt-Left arrow) Same as \f3b\fP.
+.TP 10
+.B ^[[1;5D
+(Ctrl-Left arrow) Same as \f3b\fP.
+.TP 10
+.B ^[[1;9D
+(iTerm2 Alt-Left arrow) Same as \f3b\fP.
+.TP 10
+.B ^[[1;3C
+(Alt-Right arrow) Same as \f3w\fP.
+.TP 10
+.B ^[[1;5C
+(Ctrl-Right arrow) Same as \f3w\fP.
+.TP 10
+.B ^[[1;9C
+(iTerm2 Alt-Right arrow) Same as \f3w\fP.
+.TP 10
+.B ^[[2~
+(Insert) Same as \f3i\fP.
+.TP 10
+.B ^[[3;5~
+(Ctrl-Delete) Same as \f3dw\fP.
+.TP 10
+.B ^[OA
+(Up Arrow) Same as \f3^[[A\fP.
+.TP 10
+.B ^[OB
+(Down Arrow) Same as \f3^[[B\fP.
+.TP 10
+.B ^[OC
+(Right Arrow) Same as \f3^[[C\fP.
+.TP 10
+.B ^[OD
+(Left Arrow) Same as \f3^[[D\fP.
+.TP 10
+.B ^[O5C
+(Ctrl-Right Arrow) Same as \f3w\fP.
+.TP 10
+.B ^[O5D
+(Ctrl-Left Arrow) Same as \f3b\fP.
+.TP 10
 .B ^
 Cursor to first non-blank character in line.
 .TP 10
@@ -5446,9 +5551,18 @@ Cursor to end of line.
 .B ^[[F
 (End) Same as \f3$\fP.
 .TP 10
+.B ^[[4~
+Same as \f3$\fP.
+.TP 10
+.B ^[[8~
+Same as \f3$\fP.
+.TP 10
 .B ^[[Y
 Same as \f3$\fP.
 .TP 10
+.B ^G
+Exit reverse search mode.
+.TP 10
 .B %
 Moves to balancing
 .BR ( ,