Implement new line editing "library"

Losing tab complete and text macros, for now.

This new implementation works on an instance of a struct and does
not interact with the rest of catgirl, making it possible to copy
into another project. Unlike existing line editing libraries, this
one is entirely abstract and can be rendered externally.

My goal with this library is to be able to implement vi mode. Since
it operates on struct instances rather than globals, it might also
be possible to give catgirl separate line editing buffers for each
window, which would be a nice UX improvement.

6 files changed, 358 insertions, 301 deletions

diff --git a/Makefile b/Makefile
index 83ead95..9e6392b 100644
--- a/Makefile
+++ b/Makefile
@@ -32,7 +32,7 @@ all: catgirl
 catgirl: ${OBJS}
 	${CC} ${LDFLAGS} ${OBJS} ${LDLIBS} -o $@
 
-${OBJS}: chat.h
+${OBJS}: chat.h edit.h
 
 tags: *.[ch]
 	ctags -w *.[ch]
diff --git a/chat.c b/chat.c
index 4898411..454ae31 100644
--- a/chat.c
+++ b/chat.c
@@ -371,7 +371,6 @@ int main(int argc, char *argv[]) {
 	set(&network.name, host);
 	set(&self.nick, "*");
 
-	editCompleteAdd();
 	commandCompleteAdd();
 
 	ircConfig(insecure, trust, cert, priv);
diff --git a/chat.h b/chat.h
index 753d1a3..8a9a48f 100644
--- a/chat.h
+++ b/chat.h
@@ -341,31 +341,6 @@ int bufferReflow(
 	struct Buffer *buffer, int cols, enum Heat thresh, size_t tail
 );
 
-enum Edit {
-	EditHead,
-	EditTail,
-	EditPrev,
-	EditNext,
-	EditPrevWord,
-	EditNextWord,
-	EditDeleteHead,
-	EditDeleteTail,
-	EditDeletePrev,
-	EditDeleteNext,
-	EditDeletePrevWord,
-	EditDeleteNextWord,
-	EditPaste,
-	EditTranspose,
-	EditCollapse,
-	EditInsert,
-	EditComplete,
-	EditExpand,
-	EditEnter,
-};
-void edit(uint id, enum Edit op, wchar_t ch);
-char *editBuffer(size_t *pos);
-void editCompleteAdd(void);
-
 const char *complete(uint id, const char *prefix);
 const char *completeSubstr(uint id, const char *substr);
 void completeAccept(void);
diff --git a/edit.c b/edit.c
index 66b5302..21061d7 100644
--- a/edit.c
+++ b/edit.c
@@ -1,4 +1,4 @@
-/* Copyright (C) 2020  C. McEnroe <june@causal.agency>
+/* Copyright (C) 2020, 2022  June McEnroe <june@causal.agency>
  *
  * This program is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -13,8 +13,6 @@
  * You should have received a copy of the GNU General Public License
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  *
- * Additional permission under GNU GPL version 3 section 7:
- *
  * If you modify this Program, or any covered work, by linking or
  * combining it with OpenSSL (or a modified version of that library),
  * containing parts covered by the terms of the OpenSSL License and the
@@ -25,282 +23,272 @@
  * covered work.
  */
 
-#include <assert.h>
+#include <errno.h>
 #include <limits.h>
 #include <stdbool.h>
-#include <stdio.h>
 #include <stdlib.h>
 #include <wchar.h>
 #include <wctype.h>
 
-#include "chat.h"
+#include "edit.h"
+
+static bool isword(wchar_t ch) {
+	return !iswspace(ch) && !iswpunct(ch);
+}
 
-enum { Cap = 1024 };
-static wchar_t buf[Cap];
-static size_t len;
-static size_t pos;
+void editFree(struct Edit *e) {
+	free(e->buf);
+	free(e->cut.buf);
+	free(e->mbs.buf);
+	e->pos = e->len = e->cap = 0;
+	e->cut.len = 0;
+	e->mbs.pos = e->mbs.len = 0;
+}
 
-char *editBuffer(size_t *mbsPos) {
-	static char mbs[MB_LEN_MAX * Cap];
+char *editString(struct Edit *e) {
+	size_t cap = e->len * MB_CUR_MAX + 1;
+	char *buf = realloc(e->mbs.buf, cap);
+	if (!buf) return NULL;
+	e->mbs.buf = buf;
 
-	const wchar_t *ptr = buf;
-	size_t mbsLen = wcsnrtombs(mbs, &ptr, pos, sizeof(mbs) - 1, NULL);
-	assert(mbsLen != (size_t)-1);
-	if (mbsPos) *mbsPos = mbsLen;
+	const wchar_t *ptr = e->buf;
+	e->mbs.len = wcsnrtombs(e->mbs.buf, &ptr, e->pos, cap-1, NULL);
+	if (e->mbs.len == (size_t)-1) return NULL;
+	e->mbs.pos = e->mbs.len;
 
-	ptr = &buf[pos];
+	ptr = &e->buf[e->pos];
 	size_t n = wcsnrtombs(
-		&mbs[mbsLen], &ptr, len - pos, sizeof(mbs) - mbsLen - 1, NULL
+		&e->mbs.buf[e->mbs.len], &ptr, e->len - e->pos,
+		cap-1 - e->mbs.len, NULL
 	);
-	assert(n != (size_t)-1);
-	mbsLen += n;
-
-	mbs[mbsLen] = '\0';
-	return mbs;
-}
-
-static struct {
-	wchar_t buf[Cap];
-	size_t len;
-} cut;
+	if (n == (size_t)-1) return NULL;
+	e->mbs.len += n;
 
-static bool reserve(size_t index, size_t count) {
-	if (len + count > Cap) return false;
-	wmemmove(&buf[index + count], &buf[index], len - index);
-	len += count;
-	return true;
+	e->mbs.buf[e->mbs.len] = '\0';
+	return e->mbs.buf;
 }
 
-static void delete(bool copy, size_t index, size_t count) {
-	if (index + count > len) return;
-	if (copy) {
-		wmemcpy(cut.buf, &buf[index], count);
-		cut.len = count;
+int editReserve(struct Edit *e, size_t index, size_t count) {
+	if (index > e->len) {
+		errno = EINVAL;
+		return -1;
 	}
-	wmemmove(&buf[index], &buf[index + count], len - index - count);
-	len -= count;
-}
-
-static const struct {
-	const wchar_t *name;
-	const wchar_t *string;
-} Macros[] = {
-	{ L"\\banhammer", L"▬▬▬▬▬▬▬▋ Ò╭╮Ó" },
-	{ L"\\bear", L"ʕっ•ᴥ•ʔっ" },
-	{ L"\\blush", L"（˶′◡‵˶）" },
-	{ L"\\com", L"\0038,4\2 ☭ " },
-	{ L"\\cool", L"(⌐■_■)" },
-	{ L"\\flip", L"(╯°□°）╯︵ ┻━┻" },
-	{ L"\\gary", L"ᕕ( ᐛ )ᕗ" },
-	{ L"\\hug", L"（っ・∀・）っ" },
-	{ L"\\lenny", L"( ͡° ͜ʖ ͡°)" },
-	{ L"\\look", L"ಠ_ಠ" },
-	{ L"\\shrug", L"¯\\_(ツ)_/¯" },
-	{ L"\\unflip", L"┬─┬ノ(º_ºノ)" },
-	{ L"\\wave", L"ヾ(＾∇＾)" },
-};
-
-void editCompleteAdd(void) {
-	char mbs[256];
-	for (size_t i = 0; i < ARRAY_LEN(Macros); ++i) {
-		size_t n = wcstombs(mbs, Macros[i].name, sizeof(mbs));
-		assert(n != (size_t)-1);
-		completeAdd(None, mbs, Default);
+	if (e->len + count > e->cap) {
+		size_t cap = (e->cap ? e->cap * 2 : 256);
+		wchar_t *buf = realloc(e->buf, sizeof(*buf) * cap);
+		if (!buf) return -1;
+		e->buf = buf;
+		e->cap = cap;
 	}
+	wmemmove(&e->buf[index + count], &e->buf[index], e->len - index);
+	e->len += count;
+	return 0;
 }
 
-static void macroExpand(void) {
-	size_t macro = pos;
-	while (macro && buf[macro] != L'\\') macro--;
-	if (macro == pos) return;
-	for (size_t i = 0; i < ARRAY_LEN(Macros); ++i) {
-		if (wcsncmp(Macros[i].name, &buf[macro], pos - macro)) continue;
-		if (wcstombs(NULL, Macros[i].string, 0) == (size_t)-1) continue;
-		delete(false, macro, pos - macro);
-		pos = macro;
-		size_t expand = wcslen(Macros[i].string);
-		if (reserve(macro, expand)) {
-			wcsncpy(&buf[macro], Macros[i].string, expand);
-			pos += expand;
-		}
+int editCopy(struct Edit *e, size_t index, size_t count) {
+	if (index + count > e->len) {
+		errno = EINVAL;
+		return -1;
 	}
+	wchar_t *buf = realloc(e->cut.buf, sizeof(*buf) * count);
+	if (!buf) return -1;
+	e->cut.buf = buf;
+	wmemcpy(e->cut.buf, &e->buf[index], count);
+	e->cut.len = count;
+	return 0;
 }
 
-static struct {
-	size_t pos;
-	size_t pre;
-	size_t len;
-	bool suffix;
-} tab;
-
-static void tabComplete(uint id) {
-	if (!tab.len) {
-		tab.pos = pos;
-		while (tab.pos && !iswspace(buf[tab.pos - 1])) tab.pos--;
-		if (tab.pos == pos) return;
-		tab.pre = pos - tab.pos;
-		tab.len = tab.pre;
-		tab.suffix = true;
-	}
-
-	char mbs[MB_LEN_MAX * Cap];
-	const wchar_t *ptr = &buf[tab.pos];
-	size_t n = wcsnrtombs(mbs, &ptr, tab.pre, sizeof(mbs) - 1, NULL);
-	assert(n != (size_t)-1);
-	mbs[n] = '\0';
-
-	const char *comp = complete(id, mbs);
-	if (!comp) {
-		comp = complete(id, mbs);
-		tab.suffix ^= true;
-	}
-	if (!comp) {
-		tab.len = 0;
-		return;
-	}
-
-	wchar_t wcs[Cap];
-	n = mbstowcs(wcs, comp, Cap);
-	assert(n != (size_t)-1);
-	if (tab.pos + n + 2 > Cap) {
-		completeReject();
-		tab.len = 0;
-		return;
-	}
-
-	bool colon = (tab.len >= 2 && buf[tab.pos + tab.len - 2] == L':');
-
-	delete(false, tab.pos, tab.len);
-	tab.len = n;
-	if (wcs[0] == L'\\' || wcschr(wcs, L' ')) {
-		reserve(tab.pos, tab.len);
-	} else if (wcs[0] != L'/' && tab.suffix && (!tab.pos || colon)) {
-		tab.len += 2;
-		reserve(tab.pos, tab.len);
-		buf[tab.pos + n + 0] = L':';
-		buf[tab.pos + n + 1] = L' ';
-	} else if (tab.suffix && tab.pos >= 2 && buf[tab.pos - 2] == L':') {
-		tab.len += 2;
-		reserve(tab.pos, tab.len);
-		buf[tab.pos - 2] = L',';
-		buf[tab.pos + n + 0] = L':';
-		buf[tab.pos + n + 1] = L' ';
-	} else {
-		tab.len++;
-		reserve(tab.pos, tab.len);
-		if (!tab.suffix && tab.pos >= 2 && buf[tab.pos - 2] == L',') {
-			buf[tab.pos - 2] = L':';
-		}
-		buf[tab.pos + n] = L' ';
+int editDelete(struct Edit *e, bool cut, size_t index, size_t count) {
+	if (index + count > e->len) {
+		errno = EINVAL;
+		return -1;
 	}
-	wmemcpy(&buf[tab.pos], wcs, n);
-	pos = tab.pos + tab.len;
-}
-
-static void tabAccept(void) {
-	completeAccept();
-	tab.len = 0;
-}
-
-static void tabReject(void) {
-	completeReject();
-	tab.len = 0;
-}
-
-static bool isword(wchar_t ch) {
-	return !iswspace(ch) && !iswpunct(ch);
+	if (cut && editCopy(e, index, count) < 0) return -1;
+	wmemmove(&e->buf[index], &e->buf[index + count], e->len - index - count);
+	e->len -= count;
+	if (e->pos > e->len) e->pos = e->len;
+	return 0;
 }
 
-void edit(uint id, enum Edit op, wchar_t ch) {
-	size_t init = pos;
-	switch (op) {
-		break; case EditHead: pos = 0;
-		break; case EditTail: pos = len;
-		break; case EditPrev: if (pos) pos--;
-		break; case EditNext: if (pos < len) pos++;
+int editFn(struct Edit *e, enum EditFn fn) {
+	int ret = 0;
+	switch (fn) {
+		break; case EditHead: e->pos = 0;
+		break; case EditTail: e->pos = e->len;
+		break; case EditPrev: if (e->pos) e->pos--;
+		break; case EditNext: if (e->pos < e->len) e->pos++;
 		break; case EditPrevWord: {
-			while (pos && !isword(buf[pos - 1])) pos--;
-			while (pos && isword(buf[pos - 1])) pos--;
+			while (e->pos && !isword(e->buf[e->pos-1])) e->pos--;
+			while (e->pos && isword(e->buf[e->pos-1])) e->pos--;
 		}
 		break; case EditNextWord: {
-			while (pos < len && isword(buf[pos])) pos++;
-			while (pos < len && !isword(buf[pos])) pos++;
+			while (e->pos < e->len && isword(e->buf[e->pos])) e->pos++;
+			while (e->pos < e->len && !isword(e->buf[e->pos])) e->pos++;
 		}
 
-		break; case EditDeleteHead: delete(true, 0, pos); pos = 0;
-		break; case EditDeleteTail: delete(true, pos, len - pos);
-		break; case EditDeletePrev: if (pos) delete(false, --pos, 1);
-		break; case EditDeleteNext: delete(false, pos, 1);
+		break; case EditDeleteHead: {
+			ret = editDelete(e, true, 0, e->pos);
+			e->pos = 0;
+		}
+		break; case EditDeleteTail: {
+			ret = editDelete(e, true, e->pos, e->len - e->pos);
+		}
+		break; case EditDeletePrev: {
+			if (e->pos) editDelete(e, false, --e->pos, 1);
+		}
+		break; case EditDeleteNext: {
+			editDelete(e, false, e->pos, 1);
+		}
 		break; case EditDeletePrevWord: {
-			if (!pos) break;
-			size_t word = pos;
-			while (word && !isword(buf[word - 1])) word--;
-			while (word && isword(buf[word - 1])) word--;
-			delete(true, word, pos - word);
-			pos = word;
+			if (!e->pos) break;
+			size_t word = e->pos;
+			while (word && !isword(e->buf[word-1])) word--;
+			while (word && isword(e->buf[word-1])) word--;
+			ret = editDelete(e, true, word, e->pos - word);
+			e->pos = word;
 		}
 		break; case EditDeleteNextWord: {
-			if (pos == len) break;
-			size_t word = pos;
-			while (word < len && !isword(buf[word])) word++;
-			while (word < len && isword(buf[word])) word++;
-			delete(true, pos, word - pos);
+			if (e->pos == e->len) break;
+			size_t word = e->pos;
+			while (word < e->len && !isword(e->buf[word])) word++;
+			while (word < e->len && isword(e->buf[word])) word++;
+			ret = editDelete(e, true, e->pos, word - e->pos);
 		}
+
 		break; case EditPaste: {
-			if (reserve(pos, cut.len)) {
-				wmemcpy(&buf[pos], cut.buf, cut.len);
-				pos += cut.len;
+			ret = editReserve(e, e->pos, e->cut.len);
+			if (ret == 0) {
+				wmemcpy(&e->buf[e->pos], e->cut.buf, e->cut.len);
+				e->pos += e->cut.len;
 			}
 		}
-
 		break; case EditTranspose: {
-			if (!pos || len < 2) break;
-			if (pos == len) pos--;
-			wchar_t t = buf[pos - 1];
-			buf[pos - 1] = buf[pos];
-			buf[pos++] = t;
+			if (e->len < 2) break;
+			if (!e->pos) e->pos++;
+			if (e->pos == e->len) e->pos--;
+			wchar_t x = e->buf[e->pos-1];
+			e->buf[e->pos-1] = e->buf[e->pos];
+			e->buf[e->pos++] = x;
 		}
 		break; case EditCollapse: {
 			size_t ws;
-			for (pos = 0; pos < len;) {
-				for (; pos < len && !iswspace(buf[pos]); ++pos);
-				for (ws = pos; ws < len && iswspace(buf[ws]); ++ws);
-				if (pos && ws < len) {
-					delete(false, pos, ws - pos - 1);
-					buf[pos++] = L' ';
+			for (e->pos = 0; e->pos < e->len;) {
+				for (; e->pos < e->len && !iswspace(e->buf[e->pos]); ++e->pos);
+				for (ws = e->pos; ws < e->len && iswspace(e->buf[ws]); ++ws);
+				if (e->pos && ws < e->len) {
+					editDelete(e, false, e->pos, ws - e->pos - 1);
+					e->buf[e->pos++] = L' ';
 				} else {
-					delete(false, pos, ws - pos);
+					editDelete(e, false, e->pos, ws - e->pos);
 				}
 			}
 		}
 
-		break; case EditInsert: {
-			char mb[MB_LEN_MAX];
-			if (wctomb(mb, ch) < 0) return;
-			if (reserve(pos, 1)) {
-				buf[pos++] = ch;
-			}
-		}
-		break; case EditComplete: {
-			tabComplete(id);
-			return;
-		}
-		break; case EditExpand: {
-			macroExpand();
-			tabAccept();
-			return;
-		}
-		break; case EditEnter: {
-			tabAccept();
-			command(id, editBuffer(NULL));
-			len = pos = 0;
-			return;
-		}
+		break; case EditClear: e->len = e->pos = 0;
 	}
+	return ret;
+}
+
+int editInsert(struct Edit *e, wchar_t ch) {
+	char mb[MB_LEN_MAX];
+	if (wctomb(mb, ch) < 0) return -1;
+	if (editReserve(e, e->pos, 1) < 0) return -1;
+	e->buf[e->pos++] = ch;
+	return 0;
+}
+
+#ifdef TEST
+#undef NDEBUG
+#include <assert.h>
+#include <string.h>
 
-	if (pos < init) {
-		tabReject();
-	} else {
-		tabAccept();
+static void fix(struct Edit *e, const char *str) {
+	editFn(e, EditClear);
+	for (const char *ch = str; *ch; ++ch) {
+		editInsert(e, (wchar_t)*ch);
 	}
 }
+
+static bool eq(struct Edit *e, const char *str1) {
+	const char *str2 = &str1[strlen(str1) + 1];
+	const char *buf = editString(e);
+	return e->mbs.pos == strlen(str1)
+		&& !strncmp(buf, str1, e->mbs.pos)
+		&& !strcmp(&buf[e->mbs.pos], str2);
+}
+
+int main(void) {
+	struct Edit e = { .mode = EditEmacs };
+
+	fix(&e, "foo bar");
+	editFn(&e, EditHead);
+	assert(eq(&e, "\0foo bar"));
+	editFn(&e, EditTail);
+	assert(eq(&e, "foo bar\0"));
+	editFn(&e, EditPrev);
+	assert(eq(&e, "foo ba\0r"));
+	editFn(&e, EditNext);
+	assert(eq(&e, "foo bar\0"));
+
+	fix(&e, "foo, bar");
+	editFn(&e, EditPrevWord);
+	assert(eq(&e, "foo, \0bar"));
+	editFn(&e, EditPrevWord);
+	assert(eq(&e, "\0foo, bar"));
+	editFn(&e, EditNextWord);
+	assert(eq(&e, "foo, \0bar"));
+	editFn(&e, EditNextWord);
+	assert(eq(&e, "foo, bar\0"));
+
+	fix(&e, "foo bar");
+	editFn(&e, EditPrevWord);
+	editFn(&e, EditDeleteHead);
+	assert(eq(&e, "\0bar"));
+
+	fix(&e, "foo bar");
+	editFn(&e, EditPrevWord);
+	editFn(&e, EditDeleteTail);
+	assert(eq(&e, "foo \0"));
+
+	fix(&e, "foo bar");
+	editFn(&e, EditDeletePrev);
+	assert(eq(&e, "foo ba\0"));
+	editFn(&e, EditHead);
+	editFn(&e, EditDeleteNext);
+	assert(eq(&e, "\0oo ba"));
+
+	fix(&e, "foo, bar");
+	editFn(&e, EditDeletePrevWord);
+	assert(eq(&e, "foo, \0"));
+	editFn(&e, EditDeletePrevWord);
+	assert(eq(&e, "\0"));
+
+	fix(&e, "foo, bar");
+	editFn(&e, EditHead);
+	editFn(&e, EditDeleteNextWord);
+	assert(eq(&e, "\0, bar"));
+	editFn(&e, EditDeleteNextWord);
+	assert(eq(&e, "\0"));
+
+	fix(&e, "foo bar");
+	editFn(&e, EditDeletePrevWord);
+	editFn(&e, EditPaste);
+	assert(eq(&e, "foo bar\0"));
+	editFn(&e, EditPaste);
+	assert(eq(&e, "foo barbar\0"));
+
+	fix(&e, "bar");
+	editFn(&e, EditTranspose);
+	assert(eq(&e, "bra\0"));
+	editFn(&e, EditHead);
+	editFn(&e, EditTranspose);
+	assert(eq(&e, "rb\0a"));
+	editFn(&e, EditTranspose);
+	assert(eq(&e, "rab\0"));
+
+	fix(&e, "  foo  bar  ");
+	editFn(&e, EditCollapse);
+	assert(eq(&e, "foo bar\0"));
+}
+
+#endif /* TEST */
diff --git a/edit.h b/edit.h
new file mode 100644
index 0000000..57edfc1
--- /dev/null
+++ b/edit.h
@@ -0,0 +1,91 @@
+/* Copyright (C) 2022  June McEnroe <june@causal.agency>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ * If you modify this Program, or any covered work, by linking or
+ * combining it with OpenSSL (or a modified version of that library),
+ * containing parts covered by the terms of the OpenSSL License and the
+ * original SSLeay license, the licensors of this Program grant you
+ * additional permission to convey the resulting work. Corresponding
+ * Source for a non-source form of such a combination shall include the
+ * source code for the parts of OpenSSL used as well as that of the
+ * covered work.
+ */
+
+#include <stdbool.h>
+#include <stddef.h>
+
+enum EditMode {
+	EditEmacs,
+};
+
+struct Edit {
+	enum EditMode mode;
+	wchar_t *buf;
+	size_t pos;
+	size_t len;
+	size_t cap;
+	struct {
+		wchar_t *buf;
+		size_t len;
+	} cut;
+	struct {
+		char *buf;
+		size_t pos;
+		size_t len;
+	} mbs;
+};
+
+enum EditFn {
+	EditHead,
+	EditTail,
+	EditPrev,
+	EditNext,
+	EditPrevWord,
+	EditNextWord,
+	EditDeleteHead,
+	EditDeleteTail,
+	EditDeletePrev,
+	EditDeleteNext,
+	EditDeletePrevWord,
+	EditDeleteNextWord,
+	EditPaste,
+	EditTranspose,
+	EditCollapse,
+	EditClear,
+};
+
+// Perform an editing function.
+int editFn(struct Edit *e, enum EditFn fn);
+
+// Perform a vi-mode editing function.
+int editVi(struct Edit *e, wchar_t ch);
+
+// Insert a character at the cursor.
+int editInsert(struct Edit *e, wchar_t ch);
+
+// Convert the buffer to a multi-byte string stored in e->mbs.
+char *editString(struct Edit *e);
+
+// Free all buffers.
+void editFree(struct Edit *e);
+
+// Reserve a range in the buffer.
+int editReserve(struct Edit *e, size_t index, size_t count);
+
+// Copy a range of the buffer into e->cut.
+int editCopy(struct Edit *e, size_t index, size_t count);
+
+// Delete a range from the buffer. If cut is true, copy the deleted portion.
+int editDelete(struct Edit *e, bool cut, size_t index, size_t count);
diff --git a/ui.c b/ui.c
index 3df0cd6..212d205 100644
--- a/ui.c
+++ b/ui.c
@@ -54,6 +54,7 @@
 #endif
 
 #include "chat.h"
+#include "edit.h"
 
 // Annoying stuff from <term.h>:
 #undef lines
@@ -752,9 +753,10 @@ static char *inputStop(
 	return stop;
 }
 
+static struct Edit edit;
+
 static void inputUpdate(void) {
-	size_t pos;
-	char *buf = editBuffer(&pos);
+	char *buf = editString(&edit);
 	struct Window *window = windows.ptrs[windows.show];
 
 	const char *prefix = "";
@@ -786,7 +788,7 @@ static void inputUpdate(void) {
 	} else {
 		prompt = "";
 	}
-	if (skip > &buf[pos]) {
+	if (skip > &buf[edit.mbs.pos]) {
 		prefix = prompt = suffix = "";
 		skip = buf;
 	}
@@ -803,10 +805,10 @@ static void inputUpdate(void) {
 	waddstr(input, suffix);
 	getyx(input, y, x);
 
-	int posx;
+	int pos;
 	struct Style style = styleInput;
-	inputStop(styleInput, &style, skip, &buf[pos]);
-	getyx(input, y, posx);
+	inputStop(styleInput, &style, skip, &buf[edit.mbs.pos]);
+	getyx(input, y, pos);
 	wmove(input, y, x);
 
 	style = styleInput;
@@ -818,7 +820,7 @@ static void inputUpdate(void) {
 	}
 	inputAdd(styleInput, &style, ptr);
 	wclrtoeol(input);
-	wmove(input, y, posx);
+	wmove(input, y, pos);
 }
 
 void uiWindows(void) {
@@ -965,6 +967,11 @@ static void showAuto(void) {
 	}
 }
 
+static void inputEnter(uint id) {
+	command(id, editString(&edit));
+	editFn(&edit, EditClear);
+}
+
 static void keyCode(int code) {
 	struct Window *window = windows.ptrs[windows.show];
 	uint id = window->id;
@@ -973,7 +980,7 @@ static void keyCode(int code) {
 		break; case KeyFocusIn:  unmark(window);
 		break; case KeyFocusOut: mark(window);
 
-		break; case KeyMetaEnter: edit(id, EditInsert, L'\n');
+		break; case KeyMetaEnter: editInsert(&edit, L'\n');
 		break; case KeyMetaEqual: window->mute ^= true; statusUpdate();
 		break; case KeyMetaMinus: incThresh(window, -1);
 		break; case KeyMetaPlus:  incThresh(window, +1);
@@ -984,32 +991,32 @@ static void keyCode(int code) {
 
 		break; case KeyMeta0 ... KeyMeta9: uiShowNum(code - KeyMeta0);
 		break; case KeyMetaA: showAuto();
-		break; case KeyMetaB: edit(id, EditPrevWord, 0);
-		break; case KeyMetaD: edit(id, EditDeleteNextWord, 0);
-		break; case KeyMetaF: edit(id, EditNextWord, 0);
+		break; case KeyMetaB: editFn(&edit, EditPrevWord);
+		break; case KeyMetaD: editFn(&edit, EditDeleteNextWord);
+		break; case KeyMetaF: editFn(&edit, EditNextWord);
 		break; case KeyMetaL: windowList(window);
 		break; case KeyMetaM: uiWrite(id, Warm, NULL, "");
 		break; case KeyMetaN: scrollHot(window, +1);
 		break; case KeyMetaP: scrollHot(window, -1);
-		break; case KeyMetaQ: edit(id, EditCollapse, 0);
+		break; case KeyMetaQ: editFn(&edit, EditCollapse);
 		break; case KeyMetaS: spoilerReveal ^= true; mainUpdate();
 		break; case KeyMetaT: toggleTime(window);
 		break; case KeyMetaU: scrollTo(window, window->unreadHard);
 		break; case KeyMetaV: scrollPage(window, +1);
 
-		break; case KeyCtrlLeft: edit(id, EditPrevWord, 0);
-		break; case KeyCtrlRight: edit(id, EditNextWord, 0);
+		break; case KeyCtrlLeft: editFn(&edit, EditPrevWord);
+		break; case KeyCtrlRight: editFn(&edit, EditNextWord);
 
-		break; case KEY_BACKSPACE: edit(id, EditDeletePrev, 0);
-		break; case KEY_DC: edit(id, EditDeleteNext, 0);
+		break; case KEY_BACKSPACE: editFn(&edit, EditDeletePrev);
+		break; case KEY_DC: editFn(&edit, EditDeleteNext);
 		break; case KEY_DOWN: windowScroll(window, -1);
-		break; case KEY_END: edit(id, EditTail, 0);
-		break; case KEY_ENTER: edit(id, EditEnter, 0);
-		break; case KEY_HOME: edit(id, EditHead, 0);
-		break; case KEY_LEFT: edit(id, EditPrev, 0);
+		break; case KEY_END: editFn(&edit, EditTail);
+		break; case KEY_ENTER: inputEnter(id);
+		break; case KEY_HOME: editFn(&edit, EditHead);
+		break; case KEY_LEFT: editFn(&edit, EditPrev);
 		break; case KEY_NPAGE: scrollPage(window, -1);
 		break; case KEY_PPAGE: scrollPage(window, +1);
-		break; case KEY_RIGHT: edit(id, EditNext, 0);
+		break; case KEY_RIGHT: editFn(&edit, EditNext);
 		break; case KEY_SEND: scrollTo(window, 0);
 		break; case KEY_SHOME: scrollTo(window, BufferCap);
 		break; case KEY_UP: windowScroll(window, +1);
@@ -1020,33 +1027,30 @@ static void keyCtrl(wchar_t ch) {
 	struct Window *window = windows.ptrs[windows.show];
 	uint id = window->id;
 	switch (ch ^ L'@') {
-		break; case L'?': edit(id, EditDeletePrev, 0);
-		break; case L'A': edit(id, EditHead, 0);
-		break; case L'B': edit(id, EditPrev, 0);
+		break; case L'?': editFn(&edit, EditDeletePrev);
+		break; case L'A': editFn(&edit, EditHead);
+		break; case L'B': editFn(&edit, EditPrev);
 		break; case L'C': raise(SIGINT);
-		break; case L'D': edit(id, EditDeleteNext, 0);
-		break; case L'E': edit(id, EditTail, 0);
-		break; case L'F': edit(id, EditNext, 0);
-		break; case L'H': edit(id, EditDeletePrev, 0);
-		break; case L'I': edit(id, EditComplete, 0);
-		break; case L'J': edit(id, EditEnter, 0);
-		break; case L'K': edit(id, EditDeleteTail, 0);
+		break; case L'D': editFn(&edit, EditDeleteNext);
+		break; case L'E': editFn(&edit, EditTail);
+		break; case L'F': editFn(&edit, EditNext);
+		break; case L'H': editFn(&edit, EditDeletePrev);
+		break; case L'J': inputEnter(id);
+		break; case L'K': editFn(&edit, EditDeleteTail);
 		break; case L'L': clearok(curscr, true);
 		break; case L'N': uiShowNum(windows.show + 1);
 		break; case L'P': uiShowNum(windows.show - 1);
-		break; case L'R': scrollSearch(window, editBuffer(NULL), -1);
-		break; case L'S': scrollSearch(window, editBuffer(NULL), +1);
-		break; case L'T': edit(id, EditTranspose, 0);
-		break; case L'U': edit(id, EditDeleteHead, 0);
+		break; case L'R': scrollSearch(window, editString(&edit), -1);
+		break; case L'S': scrollSearch(window, editString(&edit), +1);
+		break; case L'T': editFn(&edit, EditTranspose);
+		break; case L'U': editFn(&edit, EditDeleteHead);
 		break; case L'V': scrollPage(window, -1);
-		break; case L'W': edit(id, EditDeletePrevWord, 0);
-		break; case L'X': edit(id, EditExpand, 0);
-		break; case L'Y': edit(id, EditPaste, 0);
+		break; case L'W': editFn(&edit, EditDeletePrevWord);
+		break; case L'Y': editFn(&edit, EditPaste);
 	}
 }
 
 static void keyStyle(wchar_t ch) {
-	uint id = windows.ptrs[windows.show]->id;
 	if (iswcntrl(ch)) ch = towlower(ch ^ L'@');
 	char buf[8] = {0};
 	enum Color color = Default;
@@ -1077,7 +1081,7 @@ static void keyStyle(wchar_t ch) {
 		snprintf(buf, sizeof(buf), "%c%02d", C, color);
 	}
 	for (char *ch = buf; *ch; ++ch) {
-		edit(id, EditInsert, *ch);
+		editInsert(&edit, *ch);
 	}
 }
 
@@ -1103,7 +1107,7 @@ void uiRead(void) {
 		} else if (ret == KEY_CODE_YES && ch == KeyPasteManual) {
 			paste ^= true;
 		} else if (paste || literal) {
-			edit(windows.ptrs[windows.show]->id, EditInsert, ch);
+			editInsert(&edit, ch);
 		} else if (ret == KEY_CODE_YES) {
 			keyCode(ch);
 		} else if (ch == (L'Z' ^ L'@')) {
@@ -1117,7 +1121,7 @@ void uiRead(void) {
 		} else if (iswcntrl(ch)) {
 			keyCtrl(ch);
 		} else {
-			edit(windows.ptrs[windows.show]->id, EditInsert, ch);
+			editInsert(&edit, ch);
 		}
 		style = false;
 		literal = false;