lchat

commit a2e85fdc57c1322c16d120d1865acc8f13f4c8bd
parent 19b4d99293ad470c98406b94935565750339b716
Author: Tom Schwindl <schwindl@posteo.de>
Date:   Thu, 29 Dec 2022 13:17:48 +0100

Introduce modes

A mode determines how keyborad input is interpreted and which keybindings
are available. Currently, there is a default- and an emacs-mode from which
the user can choose.

Diffstat:
M
Makefile
 | 
7
+++++--
M
lchat.c
 | 
9
++++++---
M
slackline.c
 | 
112
+++++++++++++++++++++++++++++++++++++++++++++++++++++--------------------------
A
slackline_emacs.c
 | 
53
+++++++++++++++++++++++++++++++++++++++++++++++++++++

4 files changed, 139 insertions(+), 42 deletions(-)
diff --git a/Makefile b/Makefile
@@ -22,8 +22,8 @@ dist:
 	tar -czf lchat-$(VERSION).tar.gz lchat-$(VERSION)
 	rm -fr lchat-$(VERSION)
 
-lchat: lchat.o slackline.o util.o
-	$(CC) -o $@ lchat.o slackline.o util.o $(LIBS)
+lchat: lchat.o slackline.o util.o slackline_emacs.o
+	$(CC) -o $@ lchat.o slackline.o slackline_emacs.o util.o $(LIBS)
 
 lchat.o: lchat.c
 	$(CC) -c $(CFLAGS) -D_BSD_SOURCE -D_XOPEN_SOURCE -D_GNU_SOURCE \
@@ -42,5 +42,8 @@ sl_test: sl_test.o slackline.o slackline.h
 slackline.o: slackline.c slackline.h
 	$(CC) -c $(CFLAGS) -o $@ slackline.c
 
+slackline_emacs.o: slackline_emacs.c slackline.h
+	$(CC) -c $(CFLAGS) -o $@ slackline_emacs.c
+
 util.o: util.c util.h
 	$(CC) -c $(CFLAGS) -D_BSD_SOURCE -o $@ util.c
diff --git a/lchat.c b/lchat.c
@@ -23,6 +23,7 @@
 #include <limits.h>
 #include <poll.h>
 #include <signal.h>
+#include <stdbool.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -183,7 +184,7 @@ main(int argc, char *argv[])
 	char *in_file = NULL;
 	char *out_file = NULL;
 
-	while ((ch = getopt(argc, argv, "an:i:eo:p:t:uh")) != -1) {
+	while ((ch = getopt(argc, argv, "an:i:eo:p:t:uhm:")) != -1) {
 		switch (ch) {
 		case 'a':
 			bell_flag = false;
@@ -217,6 +218,10 @@ main(int argc, char *argv[])
 		case 'u':
 			ucspi = true;
 			break;
+		case 'm':
+			if (strcmp(optarg, "emacs") == 0)
+				sl_mode(sl, SL_EMACS);
+			break;
 		case 'h':
 		default:
 			usage();
@@ -342,8 +347,6 @@ main(int argc, char *argv[])
 				return EXIT_SUCCESS;
 
 			switch (c) {
-			case 4:		/* eot */
-				return EXIT_SUCCESS;
 			case 13:	/* return */
 				if (sl->rlen == 0 && empty_line == false)
 					goto out;
diff --git a/slackline.c b/slackline.c
@@ -22,13 +22,14 @@
 
 #include <grapheme.h>
 
+#include "slackline_internals.h"
 #include "slackline.h"
-
-enum direction {LEFT, RIGHT, HOME, END};
+#include "util.h"
 
 struct slackline *
 sl_init(void)
 {
+	char *mode = getenv("EDITOR");
 	struct slackline *sl = malloc(sizeof *sl);
 
 	if (sl == NULL)
@@ -45,6 +46,14 @@ sl_init(void)
 
 	sl_reset(sl);
 
+	sl->mode = SL_DEFAULT;
+	if (mode != NULL) {
+		if (strcmp(mode, "emacs") == 0)
+			sl->mode = SL_EMACS;
+		else if (strcmp(mode, "vi") == 0)
+			sl->mode = SL_VI;
+	}
+
 	return sl;
 }
 
@@ -71,7 +80,13 @@ sl_reset(struct slackline *sl)
 	sl->ubuf_len = 0;
 }
 
-static size_t
+void
+sl_mode(struct slackline *sl, enum mode mode)
+{
+	sl->mode = mode;
+}
+
+size_t
 sl_postobyte(struct slackline *sl, size_t pos)
 {
 	char *ptr = &sl->buf[0];
@@ -84,13 +99,13 @@ sl_postobyte(struct slackline *sl, size_t pos)
 	return byte;
 }
 
-static char *
+char *
 sl_postoptr(struct slackline *sl, size_t pos)
 {
 	return &sl->buf[sl_postobyte(sl, pos)];
 }
 
-static void
+void
 sl_backspace(struct slackline *sl)
 {
 	char *ncur;
@@ -114,7 +129,7 @@ sl_backspace(struct slackline *sl)
 	sl->ptr = ncur;
 }
 
-static void
+void
 sl_move(struct slackline *sl, enum direction dir)
 {
 	switch (dir) {
@@ -139,21 +154,41 @@ sl_move(struct slackline *sl, enum direction dir)
 	sl->ptr = sl->buf + sl->bcur;
 }
 
-int
-sl_keystroke(struct slackline *sl, int key)
+static void
+sl_default(struct slackline *sl, int key)
 {
-	uint_least32_t cp;
-
-	if (sl == NULL || sl->rlen < sl->rcur)
-		return -1;
+	switch (key) {
+	case 27:	/* Escape */
+		sl->esc = ESC;
+		break;
+	case 21:
+		sl_reset(sl);
+		break;
+	case 23: /* ctrl+w -- erase previous word */
+		while (sl->rcur != 0 && isspace((unsigned char) *(sl->ptr-1)))
+			sl_backspace(sl);
+		while (sl->rcur != 0 && !isspace((unsigned char) *(sl->ptr-1)))
+			sl_backspace(sl);
+		break;
+	case 127:	/* backspace */
+	case 8:		/* backspace */
+		sl_backspace(sl);
+		break;
+	default:
+		break;
+	}
+}
 
+static int
+sl_esc(struct slackline *sl, int key)
+{
 	/* handle escape sequences */
 	switch (sl->esc) {
 	case ESC_NONE:
 		break;
 	case ESC:
 		sl->esc = key == '[' ? ESC_BRACKET : ESC_NONE;
-		return 0;
+		return 1;
 	case ESC_BRACKET:
 		switch (key) {
 		case 'A':	/* up    */
@@ -189,10 +224,10 @@ sl_keystroke(struct slackline *sl, int key)
 		case '9':
 			sl->nummod = key;
 			sl->esc = ESC_BRACKET_NUM;
-			return 0;
+			return 1;
 		}
 		sl->esc = ESC_NONE;
-		return 0;
+		return 1;
 	case ESC_BRACKET_NUM:
 		switch(key) {
 		case '~':
@@ -213,35 +248,38 @@ sl_keystroke(struct slackline *sl, int key)
 				break;
 			}
 			sl->esc = ESC_NONE;
-			return 0;
+			return 1;
 		}
 	}
 
-	if (!iscntrl((unsigned char) key))
-		goto compose;
+	return 0;
+}
 
-	/* handle ctl keys */
-	switch (key) {
-	case 27:	/* Escape */
-		sl->esc = ESC;
-		return 0;
-	case 127:	/* backspace */
-	case 8:		/* backspace */
-		sl_backspace(sl);
-		return 0;
-	case 21: /* ctrl+u -- clearline */
-		sl_reset(sl);
-		return 0;
-	case 23: /* ctrl+w -- erase previous word */
-		while (sl->rcur != 0 && isspace((unsigned char) *(sl->ptr-1)))
-			sl_backspace(sl);
+int
+sl_keystroke(struct slackline *sl, int key)
+{
+	uint_least32_t cp;
 
-		while (sl->rcur != 0 && !isspace((unsigned char) *(sl->ptr-1)))
-			sl_backspace(sl);
-		return 0;
-	default:
+	if (sl == NULL || sl->rlen < sl->rcur)
+		return -1;
+	if (sl_esc(sl, key))
 		return 0;
+	if (!iscntrl((unsigned char) key))
+		goto compose;
+
+	switch (sl->mode) {
+	case SL_DEFAULT:
+		sl_default(sl, key);
+		break;
+	case SL_EMACS:
+		sl_default(sl, key);
+		sl_emacs(sl, key);
+		break;
+	case SL_VI:
+		/* TODO: implement vi-mode */
+		break;
 	}
+	return 0;
 
 compose:
 	/* byte-wise composing of UTF-8 runes */
diff --git a/slackline_emacs.c b/slackline_emacs.c
@@ -0,0 +1,53 @@
+#include <stdio.h>
+#include <ctype.h>
+#include <stddef.h>
+#include <stdlib.h>
+
+#include "slackline_internals.h"
+
+void
+sl_emacs(struct slackline *sl, int key)
+{
+	char tmp;
+
+	switch (key) {
+	case 27:	/* Escape */
+		sl->esc = ESC;
+		break;
+	case 1: /* ctrl+a -- start of line */
+		sl_move(sl, HOME);
+		break;
+	case 2: /* ctrl+b -- previous char */
+		sl_move(sl, LEFT);
+		break;
+	case 4: /* ctrl+d -- delete char in front of the cursor or exit */
+		if (sl->rcur < sl->rlen) {
+			sl_move(sl, RIGHT);
+			sl_backspace(sl);
+		} else {
+			exit(EXIT_SUCCESS);
+		}
+		break;
+	case 5: /* ctrl+e -- end of line */
+		sl_move(sl, END);
+		break;
+	case 6: /* ctrl+f -- next char */
+		sl_move(sl, RIGHT);
+		break;
+	case 11: /* ctrl+k -- delete line from cursor to end */
+		for (int i = sl->rlen - sl->rcur; i > 0; --i) {
+			sl_move(sl, RIGHT);
+			sl_backspace(sl);
+		}
+		break;
+	case 20: /* ctrl+t -- swap last two chars */
+		if (sl->rcur >= 2) {
+			tmp = *sl_postoptr(sl, sl->rcur-1);
+			sl->buf[sl->rcur-1] = *sl_postoptr(sl, sl->rcur-2);
+			sl->buf[sl->rcur-2] = tmp;
+		}
+		break;
+	default:
+		break;
+	}
+}