allow opening multiple files at once + replace modes

7 files changed, 343 insertions, 186 deletions

diff --git a/arena.h b/arena.h
index 3887c6c..a5cc3dd 100644
--- a/arena.h
+++ b/arena.h
@@ -21,6 +21,7 @@ void vmem_free(void *ptr, size_t sz);
 
 Arena arena_init(size_t sz);
 void arena_free(Arena *a);
+void arena_reset(Arena *a);
 void *arena_alloc(Arena *a, size_t n, size_t align);
 void *arena_realloc(Arena *a, void *old, size_t oldsz, size_t newsz, size_t align);
 
@@ -64,6 +65,10 @@ void arena_free(Arena *a) {
 	vmem_free(a->start, a->end - a->start);
 }
 
+void arena_reset(Arena *a) {
+	a->beg = a->start;
+}
+
 void *arena_alloc(Arena *a, size_t sz, size_t align) {
 	char *p = a->beg + (-(uintptr_t)a->beg & (align - 1));
 	if (p + sz > a->end) FAIL_WITH_MSG("arena out-of-memory");
diff --git a/freelist.h b/freelist.h
new file mode 100644
index 0000000..69ef976
--- /dev/null
+++ b/freelist.h
@@ -0,0 +1,31 @@
+#ifndef FREELIST_H
+#define FREELIST_H
+
+#include "arena.h"
+
+#define FREELIST_NEW(fl, a)\
+    (__typeof__(*(fl)))freelist_new((void**)(fl), sizeof(**(fl)), _Alignof(__typeof__(**(fl))), a)
+
+#define FREELIST_FREE(fl, p)\
+    freelist_free((void **)(fl), (void *)(p))
+
+static inline void *freelist_new(void **fl, size_t sz, size_t align, Arena *a) {
+	if (*fl) {
+		void *p = *fl;
+		void *next = *(void**)p;
+		*fl = next;
+		return p;
+	} else {
+		/* must pad and align for ptr to next in freelist */
+		if (sz    < sizeof(void *))   sz    = sizeof(void *);
+		if (align < _Alignof(void *)) align = _Alignof(void *);
+		return arena_alloc(a, sz, align);
+	}
+}
+
+static inline void freelist_free(void **fl, void *p) {
+	*(void **)p = *fl;
+	*fl = p;
+}
+
+#endif
diff --git a/main.c b/main.c
index b66c9c1..892dea6 100644
--- a/main.c
+++ b/main.c
@@ -21,6 +21,7 @@
 #include "vui.h"
 #include "utf8.h"
 #include "str.h"
+#include "freelist.h"
 
 #define ED_BUF_MAX 1024
 
@@ -33,56 +34,58 @@ typedef struct {
 	EditBufType type;
 	Arena arena;
 	Str path;
-	Txt txt;
+	Txt *txt;
 	TxtLoc cur;
 } EditBuf;
 
 typedef enum {
 	MODE_NORMAL,
-	MODE_INSERT
+	MODE_INSERT,
+	MODE_REPLACE_ONE,
+	MODE_REPLACE_MULT
 } EditMode;
 
 typedef struct {
 	Arena scratch;
 	EditBuf buf[ED_BUF_MAX];
 	u32 bufn, bufi;
+	Txt *txt_free;
 	EditMode mode;
 	u32 count;
 } Editor;
 
-Arena scratch = { 0 };
-Txt txt = { 0 };
-TxtLoc cur = { 0 };
-int mode = 0;
-u32 count = 0;
+Editor e = { 0 };
 
-int ed_buf_new(Editor *e, const char *path) {
+int ed_buf_open(Editor *e, const char *path) {
 	if (e->bufn == ED_BUF_MAX) return -1;
-	u32 i = e->bufn;
 	EditBuf b = { 0 };
 	b.arena = arena_init(1L << 30);
+	b.txt = FREELIST_NEW(&e->txt_free, &b.arena);
 	if (path) {
 		b.path = str_dup(str_from_cstr(path), &b.arena);
 		b.type = ED_BUF_FILE;
-		txt_load(&b.txt, path);
+		txt_load(b.txt, path);
 	} else {
 		b.path = S("*scratch*");
 		b.type = ED_BUF_SCRATCH;
-		txt_load_empty(&b.txt);
+		txt_load_empty(b.txt);
 	}
-	b.cur = txt_end(&b.txt);
-	return i;
+	b.cur = txt_end(b.txt);
+	e->buf[e->bufn] = b;
+	return e->bufn++;
 }
 
 void ed_buf_free(EditBuf *b) {
-	txt_free(&b->txt);
+	txt_free(b->txt);
 	arena_free(&b->arena);
 }
 
 void ed_init(Editor *e) {
 	memset(e, 0, sizeof(Editor));
-	e->scratch = arena_init(1L << 30),
-	e->bufi = ed_buf_new(e, NULL);
+	e->scratch = arena_init(1L << 30);
+	e->bufi = ed_buf_open(e, NULL);
+	Str s = S("(Scratch buffer, type whatever)");
+	e->buf[e->bufi].cur = txt_insert(e->buf[e->bufi].cur, s.s, s.n);
 }
 
 void ed_fini(Editor *e) {
@@ -91,6 +94,24 @@ void ed_fini(Editor *e) {
 	}
 }
 
+u32 ed_buf_close(Editor *e, u32 i) {
+	ed_buf_free(&e->buf[i]);
+	if (i + 1 < e->bufn) {
+		MOVE(&e->buf[i], &e->buf[i+1], e->bufn - (i + 1));
+	}
+	e->bufn--;
+	return i > 0 ? i - 1 : 0;
+}
+
+int ed_buf_save(Editor *e, u32 i) {
+	EditBuf *b = &e->buf[i];
+	if (b->type == ED_BUF_FILE) {
+		return txt_save(b->txt, str_to_cstr(b->path, &e->scratch));
+	} else {
+		return 0;
+	}
+}
+
 static inline int is_space(u32 c) {
 	return c <= 0x20 && c != 0;
 }
@@ -213,7 +234,7 @@ int shell_replace(TxtLoc start, TxtLoc end, const char *cmd) {
 		{ .fd = in, .events = POLLOUT },
 		{ .fd = out, .events = POLLIN }
 	};
-	Str wrs = txt_collect_range(start, end, &scratch);
+	Str wrs = txt_collect_range(start, end, &e.scratch);
 	DYNARR(char) rds = { 0 };
 	u32 wr_i = 0;
 	while ((pfds[0].fd >= 0 || pfds[1].fd >= 0) && poll(pfds, 2, 200) >= 0) {
@@ -233,7 +254,7 @@ int shell_replace(TxtLoc start, TxtLoc end, const char *cmd) {
 			pfds[0].fd = -1;
 		}
 		if (pfds[1].revents & POLLIN) {
-			DA_AFIT(&rds, &scratch, rds.n + (-rds.n & (chunksz-1)) + chunksz);
+			DA_AFIT(&rds, &e.scratch, rds.n + (-rds.n & (chunksz-1)) + chunksz);
 			isize r = read(out, &rds.v[rds.n], chunksz);
 			if (r > 0) {
 				rds.n += r;
@@ -255,22 +276,29 @@ int shell_replace(TxtLoc start, TxtLoc end, const char *cmd) {
 	 * final one until it matches or gets too small.
 	 */
 	if (!txt_range_equal(start, end, (Str){rds.v,rds.n})) {
-		u32 b = txt_ofs(cur);
+		EditBuf *eb = &e.buf[e.bufi];
+		u32 b = txt_ofs(eb->cur);
 		start = txt_delete_range(start, end);
 		end = txt_insert(start, rds.v, rds.n);
-		cur = txt_at(start.t, b);
+		eb->cur = txt_at(start.t, b);
 	}
 	return 0;
 }
 
-int shell_run(const char *cmd) {
-	vui_disable();
-	int r = system(cmd);
-	printf("[Press any key to resume editing]");
+#define ANY_KEY_PROMPT "[Press any key to resume editing]"
+
+static void press_any_key(void) {
+	printf("%s", ANY_KEY_PROMPT);
 	fflush(stdout);
 	vui_enable();
 	vui_key();
 	vui_redraw();
+}
+
+int shell_run(const char *cmd) {
+	vui_disable();
+	int r = system(cmd);
+	press_any_key();
 	return r;
 }
 
@@ -279,14 +307,14 @@ int shell_run(const char *cmd) {
 #define ODD_ATTR (FG_CYAN | BG_BLACK)
 #define EVEN_ATTR (FG_WHITE | BG_BLACK)
 
-void find_view_window(TxtLoc l, TxtLoc *start, TxtLoc *end) {
-	u32 u = LINES / 2;
+void find_view_window(TxtLoc l, TxtLoc *start, TxtLoc *end, u32 lines) {
+	u32 u = lines / 2;
 	TxtLoc a = l;
 	for (u32 i = 0; i < u; i++) a = prev_newline(a);
 	u32 n = 0;
 	TxtLoc b = a;
-	while (!at_end(b) && n++ < LINES) b = next_newline(b);
-	while (!at_start(a) && n++ < LINES) a = prev_newline(a);
+	while (!at_end(b) && n++ < lines) b = next_newline(b);
+	while (!at_start(a) && n++ < lines) a = prev_newline(a);
 	if (!at_start(a) && txt_byte(a) == '\n') a = bnext(a);
 	*start = a;
 	*end = b;
@@ -294,20 +322,37 @@ void find_view_window(TxtLoc l, TxtLoc *start, TxtLoc *end) {
 
 void draw(void *ctx) {
 	(void)ctx;
+	EditBuf *eb = &e.buf[e.bufi];
+
 	vui_clear();
 	int lmarg = 0;
-	int x = lmarg, y = 0;
+	int x = lmarg, y = 1;
 	TxtLoc start, end;
-	find_view_window(cur, &start, &end);
+	find_view_window(eb->cur, &start, &end, LINES - 1);
 
-	vui_aprintf(-1, 0, ODD_ATTR, "%u piece(s)", txt.ptbl.n);
-	for (u32 i = 0; i < txt.ptbl.n; i++) {
-		TxtPiece *p = &txt.ptbl.v[i];
+	vui_aprintf(-1, 0, ODD_ATTR, "%u piece(s)", eb->txt->ptbl.n);
+	for (u32 i = 0; i < eb->txt->ptbl.n; i++) {
+		TxtPiece *p = &eb->txt->ptbl.v[i];
 		VuiAttr a = i&1 ? ODD_ATTR : EVEN_ATTR;
 		vui_aprintf(-1, i+1, a, "%u, %u (%s)", p->ofs, p->n, p->buf == TXT_ADD ? "add" : "src");
 	}
 
-	TxtLoc l = cur;
+	{
+		VuiAttr norm = FG_WHITE | BG_BLACK;
+		VuiAttr sel = FG_BLACK | BG_WHITE;
+		int x = 0;
+		for (u32 i = 0; i < e.bufn; i++) {
+			EditBuf *b = &e.buf[i];
+			VuiAttr a = i == e.bufi ? sel : norm;
+			x += vui_aprintf(x, 0, a, " %.*s", (int)b->path.n, b->path.s);
+			if (b->type == ED_BUF_FILE && b->txt->dirty) x += vui_putsa(x, 0, "* ", a);
+			else vui_chra(x++, 0, ' ', a);
+		}
+		int n = COLS;
+		while (x < n) vui_chra(x++, 0, ' ', norm);
+	}
+
+	TxtLoc l = eb->cur;
 	int cur_found = 0;
 	while (txt_before(start, end)) {
 		if (l.p == start.p && l.i == start.i) {
@@ -325,14 +370,16 @@ void draw(void *ctx) {
 			vui_chr(x++, y, c);
 		}
 	}
-	ASSERT(start.i <= txt.ptbl.v[start.p].n);
+
+	ASSERT(start.i <= eb->txt->ptbl.v[start.p].n);
 	if (!cur_found) vui_curs_pos(x, y);
+	/*
 	u32 c = txt_chr(l);
-	vui_printf(-1, -4, "%u", count);
-	vui_aprintf(-1, -3, mode ? FG_BCYAN : FG_CYAN, "%s", mode ? "INSERT" : "NORMAL");
-	vui_printf(-1, -1, "%u - %u.%u - %02x (%c)", txt_ofs(cur), l.p, l.i, c, (c < 0x20 || c > 0x7e) ? ' ' : c);
-	u32 used = scratch.beg - scratch.start, max = scratch.end - scratch.start;
-	vui_printf(-1, -2, "scratch %.02f/%.02fk", used/1024.0, max/1024.0);
+	vui_printf(-1, -4, "%u", e.count);
+	vui_aprintf(-1, -3, e.mode ? FG_BCYAN : FG_CYAN, "%s", e.mode ? "INSERT" : "NORMAL");
+	vui_printf(-1, -1, "%u - %u.%u - %02x (%c)", txt_ofs(eb->cur), l.p, l.i, c, (c < 0x20 || c > 0x7e) ? ' ' : c);
+	u32 used = e.scratch.beg - e.scratch.start, max = e.scratch.end - e.scratch.start;
+	vui_printf(-1, -2, "e.scratch %.02f/%.02fk", used/1024.0, max/1024.0);*/
 }
 
 int motion(TxtLoc *lp, u32 c) {
@@ -341,13 +388,13 @@ int motion(TxtLoc *lp, u32 c) {
 	for (;;) {
 		switch (c) {
 		case '0':
-			if (!count) goto loop;
+			if (!e.count) goto loop;
 		case '1': case '2': case '3': case '4':
 		case '5': case '6': case '7': case '8': case '9':
-			count = (count % 100000000) * 10 + c - '0';
+			e.count = (e.count % 100000000) * 10 + c - '0';
 			break;
 		case KEY_ESC:
-			count = 0;
+			e.count = 0;
 			return 0;
 		default:
 			goto loop;
@@ -407,11 +454,11 @@ loop:
 		break;
 	case KEY_HOME | KEY_CTRL_BIT:
 	case 'g':
-		l = txt_start(&txt);
+		l = txt_start(l.t);
 		break;
 	case KEY_END | KEY_CTRL_BIT:
 	case 'G':
-		l = txt_end(&txt);
+		l = txt_end(l.t);
 		break;
 	case 'f': {
 		u32 k = vui_key();
@@ -442,43 +489,15 @@ loop:
 	default:
 		return 0;
 	}
-	if (count > 1 && (txt_before(l, last_loc) || txt_after(l, last_loc))) {
-		count--;
+	if (e.count > 1 && (txt_before(l, last_loc) || txt_after(l, last_loc))) {
+		e.count--;
 		goto loop;
 	}
-	count = 0;
+	e.count = 0;
 	*lp = l;
 	return 1;
 }
 
-#include <time.h>
-
-void test_edits(void) {
-	for (u32 iter = 0; iter < 8192; iter++) {
-		ASSERT(iter != 385);
-		u32 n = rand() % 100;
-		cur = txt_at(&txt, rand() % txt.len);
-		if (rand() & 1) {
-			cur = txt_delete(cur, n);
-		} else {
-			for (u32 j = 0; j < n; j++) {
-				const char ch[] = {
-					'a','b','c','d','e','f','g','h','j','k','l','i',
-					'm','o','p','q','r','s','t','u','v','w','x','y','z','\n',
-					'A','B','C','D','E','F','G','H','J','K','L','I',
-					'M','O','P','Q','R','S','T','U','V','W','X','Y','Z',
-				};
-				cur = txt_insert_c(cur, ch[rand() % COUNTOF(ch)]);
-			}
-		}
-		if (txt.ptbl.n > 1) {
-			for (u32 i = 0; i < txt.ptbl.n; i++) {
-				ASSERT(txt.ptbl.v[i].n > 0);
-			}
-		}
-	}
-}
-
 TxtLoc ins_newline(TxtLoc l) {
 	u32 tabs = 0;
 	TxtLoc start = start_of_line(l);
@@ -498,8 +517,8 @@ static Str normalize_path(Str s) {
 			return (Str) { 0, 0 };
 		}
 		Str d = str_from_cstr(pwd);
-		str_catc(&d, '/', &scratch);
-		str_cat(&d, s, &scratch);
+		str_catc(&d, '/', &e.scratch);
+		str_cat(&d, s, &e.scratch);
 		s = d;
 	}
 	DYNARR(Str) bits = { 0 };
@@ -510,14 +529,14 @@ static Str normalize_path(Str s) {
 		} else if (str_eql(c.head, S("."))) {
 			/* do nothing */
 		} else if (c.head.n > 0) {
-			DA_APUSH(&bits, &scratch, c.head);
+			DA_APUSH(&bits, &e.scratch, c.head);
 		}
 		s = c.tail;
 	}
 	Str path = { 0 };
 	for (u32 i = 0; i < bits.n; i++) {
-		str_catc(&path, '/', &scratch);
-		str_cat(&path, bits.v[i], &scratch);
+		str_catc(&path, '/', &e.scratch);
+		str_cat(&path, bits.v[i], &e.scratch);
 	}
 	return path;
 }
@@ -534,14 +553,49 @@ int is_wed_path(Str path) {
 	return str_starts(normalize_path(path), S(WED_DEV_DIR));
 }
 
+void str_cat_u32(Str *out, u32 c, Arena *a) {
+	char buf[32];
+	u32 n = 0;
+	do {
+		buf[32 - ++n] = (c % 10) + '0';
+		c /= 10;
+	} while (c);
+	str_cat(out, (Str) { &buf[sizeof(buf) - n], n }, a);
+}
+
+int str_to_u32(Str s, u32 *out) {
+	u32 x = 0;
+	for (u32 i = 0; i < s.n; i++) {
+		char c = s.s[i];
+		if (!(c >= '0' && c <= '9')) return -1;
+		x = (x * 10) + c - '0';
+	}
+	*out = x;
+	return 0;
+}
+
+void make_edit_args(Str *a) {
+	for (u32 i = 0; i < e.bufn; i++) {
+		if (e.buf[i].type != ED_BUF_FILE) continue;
+		if (i > 0) str_catc(a, ' ', &e.scratch);
+		str_cat(a, e.buf[i].path, &e.scratch);
+		str_cat(a, S("@"), &e.scratch);
+		str_cat_u32(a, txt_ofs(e.buf[i].cur), &e.scratch);
+	}
+}
+
 static void run_file(Str path, int debugp) {
 	path = normalize_path(path);
 	if (is_wed_path(path)) {
-		vui_fini();
-		system(debugp ? "make DEBUG=1" : "make");
-		char ofs[32];
-		sprintf(ofs, "-b%d", txt_ofs(cur));
-		execl(WED_DEV_EXE, WED_DEV_EXE, ofs, str_to_cstr(path, &scratch), 0);
+		vui_disable();
+		if (system(debugp ? "make DEBUG=1" : "make")) {
+			press_any_key();
+		} else {
+			vui_fini();
+			Str cmd = S("exec " WED_DEV_EXE " ");
+			make_edit_args(&cmd);
+			execl("/bin/sh", "sh", "-c", str_to_cstr(cmd, &e.scratch), 0);
+		}
 	} else {
 		shell_run(debugp ? "make DEBUG=1 run" : "make run");
 	}
@@ -550,126 +604,161 @@ static void run_file(Str path, int debugp) {
 static void debug_file(Str path) {
 	if (is_wed_path(path)) {
 		vui_disable();
-		system("make DEBUG=1");
-		char ofs[32];
-		sprintf(ofs, "-b%d", txt_ofs(cur));
-		Str cmd = S("exec gdb -ex run --args " WED_DEV_EXE " ");
-		str_cat(&cmd, str_from_cstr(ofs), &scratch);
-		execl("/bin/sh", "sh", "-c", str_to_cstr(cmd, &scratch), 0);
+		if (system("make DEBUG=1")) {
+			press_any_key();
+		} else {
+			vui_fini();
+			Str cmd = S("exec gdb -ex run --args " WED_DEV_EXE " ");
+			make_edit_args(&cmd);
+			execl("/bin/sh", "sh", "-c", str_to_cstr(cmd, &e.scratch), 0);
+		}
 	} else {
 		Str cmd = S("gdb -ex run --args ");
-		str_cat(&cmd, path, &scratch);
-		shell_run(str_to_cstr(cmd, &scratch));
+		str_cat(&cmd, path, &e.scratch);
+		shell_run(str_to_cstr(cmd, &e.scratch));
 	}
 }
 
 int main(int argc, const char **argv) {
-	/* TODO: Have a command-line argument to start editing at the given byte offset,
-	 * e.g. wed -b 1027 */
-
-	scratch = arena_init(128L << 20);
-
-	int start_ofs = -1;
-	if (argc > 1 && !strncmp(argv[1], "-b", 2)) {
-		start_ofs = atoi(argv[1] + 2);
-		if (argc > 2) {
-			MOVE(&argv[1], &argv[2], argc - 2);
+	ed_init(&e);
+
+	if (argc > 1) {
+		for (int i = 1; i < argc; i++) {
+			Str s = str_from_cstr(argv[i]);
+			Cut c = str_cut(s, '@');
+			e.bufi = ed_buf_open(&e, str_to_cstr(c.head, &e.scratch));
+			if (c.tail.n > 1) {
+				EditBuf *eb = &e.buf[e.bufi];
+				u32 ofs;
+				if (str_to_u32(c.tail, &ofs)) {
+					fprintf(stderr, "invalid byte offset in %s\n", argv[i]);
+					return 1;
+				}
+				eb->cur = txt_at(eb->txt, ofs);
+			}
 		}
-		argc--;
+	} else {
+		e.bufi = ed_buf_open(&e, "main.c");
 	}
 
-	const char *path = "main.c";
-	if (argc > 1) path = argv[1];
-
 	vui_init();
 	vui_curs_vis(1);
 	vui_redraw_fn(draw);
 
-	if (txt_load(&txt, path)) err(1, "couldn't open file");
-	cur = start_ofs < 0 ? txt_end(&txt) : txt_at(&txt, start_ofs);
-
-	for (;;) {
-		scratch.beg = scratch.start;
+	while (e.bufn > 0) {
+		arena_reset(&e.scratch);
+		EditBuf *eb = &e.buf[e.bufi];
 		draw(NULL);
-		vui_curs_shape(mode ? VUI_CURS_BAR : VUI_CURS_BLOCK);
+		
+		switch (e.mode) {
+		case MODE_NORMAL:
+			vui_curs_shape(VUI_CURS_BLOCK);
+			break;
+		case MODE_INSERT:
+			vui_curs_shape(VUI_CURS_BAR);
+			break;
+		case MODE_REPLACE_ONE:
+		case MODE_REPLACE_MULT:
+			vui_curs_shape(VUI_CURS_UNDERLINE);
+			break;
+		}
+
 		vui_blit();
 		u32 c = vui_key();
-		switch (mode) {
-		case 0:
+
+		switch (e.mode) {
+		case MODE_NORMAL:
 			switch (c) {
 			case 'q':
-				goto brk;
+				e.bufi = ed_buf_close(&e, e.bufi);
+				break;
+			case 'Q':
+				while (e.bufn > 0) e.bufi = ed_buf_close(&e, e.bufi);
+				break;
+			case '[':
+				if (e.bufi > 0) e.bufi = e.bufi - 1;
+				else e.bufi = e.bufn - 1;
+				break;
+			case ']':
+				e.bufi = (e.bufi + 1) % e.bufn;
+				break;
 			case 'z':
 			case 'Z':
 			case 0x13 /* ^S */:
-				txt_save(&txt, path);
+				ed_buf_save(&e, e.bufi);
 				//txt_load(&txt, "test.txt");
-				if (c == 'Z') goto brk;
+				if (c == 'Z') e.bufi = ed_buf_close(&e, e.bufi);
 				break;
 			case 'i':
-				mode = 1;
+				e.mode = 1;
 				break;
 			case 'a': {
-				mode = 1;
-				TxtLoc l = cur;
+				e.mode = 1;
+				TxtLoc l = eb->cur;
 				TxtLoc e = end_of_line(l);
 				l = txt_before(l, e) ? cnext(l) : e;
-				cur = l;
+				eb->cur = l;
 			} break;
 			case 'I':
-				mode = 1;
-				cur = start_of_line(cur);
+				e.mode = 1;
+				eb->cur = start_of_line(eb->cur);
 				break;
 			case 'A':
-				mode = 1;
-				cur = end_of_line(cur);
+				e.mode = 1;
+				eb->cur = end_of_line(eb->cur);
 				break;
 			case 'o':
-				mode = 1;
-				cur = ins_newline(end_of_line(cur));
+				e.mode = 1;
+				eb->cur = ins_newline(end_of_line(eb->cur));
 				break;
 			case 'O':
-				mode = 1;
-				cur = ins_newline(bprev(start_of_line(cur)));
-				if (at_start(bprev(cur))) cur = bprev(cur);
+				e.mode = 1;
+				eb->cur = ins_newline(bprev(start_of_line(eb->cur)));
+				if (at_start(bprev(eb->cur))) eb->cur = bprev(eb->cur);
 				break;
 			case 'd': {
-				TxtLoc before = cur;
-				if (motion(&cur, vui_key())) {
-					cur = txt_delete_range(before, cur);
+				TxtLoc before = eb->cur;
+				if (motion(&eb->cur, vui_key())) {
+					eb->cur = txt_delete_range(before, eb->cur);
 				}
 			} break;
 			case 'D':
-				cur = txt_delete_range(cur, end_of_line(cur));
+				eb->cur = txt_delete_range(eb->cur, end_of_line(eb->cur));
 				break;
 			case 'C':
-				cur = txt_delete_range(cur, end_of_line(cur));
-				mode = 1;
+				eb->cur = txt_delete_range(eb->cur, end_of_line(eb->cur));
+				e.mode = 1;
 				break;
 			case 'S': {
-				TxtLoc start = start_of_line(cur);
-				TxtLoc end = end_of_line(cur);
-				cur = txt_delete_range(start, end);
-				mode = 1;
+				TxtLoc start = start_of_line(eb->cur);
+				TxtLoc end = end_of_line(eb->cur);
+				eb->cur = txt_delete_range(start, end);
+				e.mode = 1;
 			} break;
 			case 'c': {
-				TxtLoc before = cur;
-				if (motion(&cur, vui_key())) {
-					cur = txt_delete_range(before, cur);
-					mode = 1;
+				TxtLoc before = eb->cur;
+				if (motion(&eb->cur, vui_key())) {
+					eb->cur = txt_delete_range(before, eb->cur);
+					e.mode = 1;
 				}
 				break;
 			}
 			case 'x':
-				cur = txt_delete_c(cnext(cur));
+				eb->cur = txt_delete_c(cnext(eb->cur));
 				break;
 			case 's':
-				cur = txt_delete_c(cnext(cur));
-				mode = 1;
+				eb->cur = txt_delete_c(cnext(eb->cur));
+				e.mode = 1;
+				break;
+			case 'r':
+				e.mode = MODE_REPLACE_ONE;
+				break;
+			case 'R':
+				e.mode = MODE_REPLACE_MULT;
 				break;
 			case 'M': {
-				TxtLoc start = prev_par(cur);
-				TxtLoc end = next_par(cur);
+				TxtLoc start = prev_par(eb->cur);
+				TxtLoc end = next_par(eb->cur);
 				if (shell_replace(start, end, "fmt -w80 -u")) {
 					err(1, "shell_replace");
 				}
@@ -677,19 +766,19 @@ int main(int argc, const char **argv) {
 			case ' ':
 				switch ((u32)vui_key()) {
 				case 'm':
-					build_file(str_from_cstr(path), 1);
+					build_file(eb->path, 1);
 					break;
 				case 'M':
-					build_file(str_from_cstr(path), 0);
+					build_file(eb->path, 0);
 					break;
 				case 'r':
-					run_file(str_from_cstr(path), 1);
+					run_file(eb->path, 1);
 					break;
 				case 'R':
-					run_file(str_from_cstr(path), 0);
+					run_file(eb->path, 0);
 					break;
 				case 'D':
-					debug_file(str_from_cstr(path));
+					debug_file(eb->path);
 					break;
 				case 'e':
 					vui_disable();
@@ -703,49 +792,68 @@ int main(int argc, const char **argv) {
 				}
 				break;
 			default:
-				motion(&cur, c);
+				motion(&eb->cur, c);
 				break;
 			}
 			break;
-		case 1:
+
+		case MODE_INSERT:
 			switch (c) {
 			case KEY_ESC:
-				if (txt_after(cur, start_of_line(cur))) {
-					cur = cprev(cur);
+				if (txt_after(eb->cur, start_of_line(eb->cur))) {
+					eb->cur = cprev(eb->cur);
 				}
-				mode = 0;
+				e.mode = 0;
 				break;
 			case KEY_BKSP:
-				cur = txt_delete_c(cur);
+				eb->cur = txt_delete_c(eb->cur);
 				break;
 			case 0x17 /* ^W */:
-				cur = txt_delete_range(prev_word(cur), cur);
+				eb->cur = txt_delete_range(prev_word(eb->cur), eb->cur);
 				break;
 			case 0x05 /* ^E */:
-				cur = txt_delete_range(cur, next_word(cur));
+				eb->cur = txt_delete_range(eb->cur, next_word(eb->cur));
 				break;
 			case 0x0c /* ^L */:
 				vui_redraw();
 				break;
 			case '\r':
-				cur = ins_newline(cur);
+				eb->cur = ins_newline(eb->cur);
 				break;
 			default:
-				if ((c == '\t' || c >= ' ') && c <= KEY_UTF8_MAX) cur = txt_insert_c(cur, c);
+				if ((c == '\t' || c >= ' ') && c <= KEY_UTF8_MAX) eb->cur = txt_insert_c(eb->cur, c);
 				break;
 			}
 			break;
-		}
-		if (mode == 1) count = 0;
-		ASSERT(txt_valid_loc(cur));
-		if (txt.ptbl.n > 1) {
-			for (u32 i = 0; i < txt.ptbl.n; i++) {
-				ASSERT(txt.ptbl.v[i].n > 0);
+
+		case MODE_REPLACE_ONE:
+			if (txt_byte(eb->cur) != '\n' && c != KEY_BKSP && c <= KEY_UTF8_MAX) {
+				eb->cur = cprev(txt_insert_c(txt_delete_c(cnext(eb->cur)), c));
 			}
+			e.mode = MODE_NORMAL;
+			break;
+
+		case MODE_REPLACE_MULT:
+			if (c == '\x1b') {
+				e.mode = MODE_NORMAL;
+				eb->cur = cprev(eb->cur);
+			} else if (c == KEY_BKSP) {
+				if (txt_byte(bprev(eb->cur)) != '\n')
+					eb->cur = cprev(eb->cur);
+			} else if (c <= KEY_UTF8_MAX) {
+				if (txt_byte(eb->cur) == '\n') {
+					eb->cur = txt_insert_c(eb->cur, c);
+				} else {
+					eb->cur = txt_insert_c(txt_delete_c(cnext(eb->cur)), c);
+				}
+			}
+			break;
 		}
+
+		if (e.mode == 1) e.count = 0;
 	}
-brk:
+
 	vui_fini();
-	arena_free(&scratch);
+	arena_free(&e.scratch);
 	return 0;
 }
diff --git a/txt.c b/txt.c
index 818e4c2..fd51bc4 100644
--- a/txt.c
+++ b/txt.c
@@ -127,6 +127,7 @@ loop:
 		goto loop;
 	}
 	ASSERT(txt_valid_loc(l));
+	l.t->dirty = 1;
 	return resolve_loc(l);
 }
 
@@ -229,6 +230,13 @@ done:
 	return 0;
 }
 
+void txt_load_empty(Txt *b) {
+	memset(b, 0, sizeof(Txt));
+	txt_buf_fit(b, TXT_SRC, 32);
+	txt_buf_fit(b, TXT_ADD, 8192);
+	txt_insert_piece(b, 0, TXT_ADD, 0, b->len);
+}
+
 int txt_save(Txt *t, const char *path) {
 	FILE *f = fopen(path, "wb");
 	if (!f) return -1;
@@ -239,6 +247,7 @@ int txt_save(Txt *t, const char *path) {
 	}
 	int e = ferror(f);
 	fclose(f);
+	t->dirty = 0;
 	return e ? -1 : 0;
 }
 
diff --git a/txt.h b/txt.h
index 6bc5dd1..e61c881 100644
--- a/txt.h
+++ b/txt.h
@@ -24,6 +24,7 @@ typedef struct {
 	DYNARR(TxtPiece) ptbl;
 	TxtBuf buf[2];
 	u32 len;
+	int dirty;
 } Txt;
 
 typedef struct {
@@ -37,6 +38,7 @@ TxtLoc txt_split_piece(TxtLoc l);
 void txt_remove_piece(Txt *b, u32 pi);
 void txt_insert_piece(Txt *b, u32 pi, TxtBufIdx buf, u32 ofs, u32 n);
 
+void txt_load_empty(Txt *b);
 int txt_load(Txt *b, const char *path);
 int txt_save(Txt *b, const char *path);
 void txt_free(Txt *b);
diff --git a/vui.c b/vui.c
index 299b394..f5d6fdd 100644
--- a/vui.c
+++ b/vui.c
@@ -615,26 +615,28 @@ static void truncate_span(int *x, unsigned *nptr) {
 	*nptr = n;
 }
 
-void vui_putsna(int x, int y, const char *s, unsigned srcn, VuiAttr a) {
+u32 vui_putsna(int x, int y, const char *s, unsigned srcn, VuiAttr a) {
 	u32 n = utf8_decode_len(s, srcn);
 	truncate_span(&x, &n);
-	if (n < 1 || y < 0 || y >= (int)LINES) return;
+	if (n < 1 || y < 0 || y >= (int)LINES) return 0;
 	VuiChar *dest = &CHR(x, y);
 	utf8_decode(dest, s, n);
 	for (u32 i = 0; i < n; i++) ASSERT(dest[i] > 0 && dest[i] <= KEY_UTF8_MAX);
+	u32 r = n;
 	for (uint16_t *pa = &ATTR(x, y); n--;) *pa++ = a;
+	return r;
 }
 
-void vui_putsn(int x, int y, const char *s, unsigned n) {
-	vui_putsna(x, y, s, n, ATTR_DEFAULT);
+u32 vui_putsn(int x, int y, const char *s, unsigned n) {
+	return vui_putsna(x, y, s, n, ATTR_DEFAULT);
 }
 
-void vui_putsa(int x, int y, const char *s, VuiAttr a) {
-	vui_putsna(x, y, s, strlen(s), a);
+u32 vui_putsa(int x, int y, const char *s, VuiAttr a) {
+	return vui_putsna(x, y, s, strlen(s), a);
 }
 
-void vui_puts(int x, int y, const char *s) {
-	vui_putsn(x, y, s, strlen(s));
+u32 vui_puts(int x, int y, const char *s) {
+	return vui_putsn(x, y, s, strlen(s));
 }
 
 int vui_avprintf(int x, int y, VuiAttr a, const char *fmt, va_list ap) {
diff --git a/vui.h b/vui.h
index ef484d0..d0dd366 100644
--- a/vui.h
+++ b/vui.h
@@ -132,10 +132,10 @@ void vui_scroll(int dx, int dy);
 void vui_chr(int x, int y, VuiChar c);
 void vui_chra(int x, int y, VuiChar c, VuiAttr a);
 
-void vui_puts(int x, int y, const char *s);
-void vui_putsa(int x, int y, const char *s, VuiAttr a);
-void vui_putsn(int x, int y, const char *s, unsigned n);
-void vui_putsna(int x, int y, const char *s, unsigned n, VuiAttr a);
+unsigned vui_puts(int x, int y, const char *s);
+unsigned vui_putsa(int x, int y, const char *s, VuiAttr a);
+unsigned vui_putsn(int x, int y, const char *s, unsigned n);
+unsigned vui_putsna(int x, int y, const char *s, unsigned n, VuiAttr a);
 
 int vui_avprintf(int x, int y, VuiAttr a, const char *fmt, va_list ap);
 int vui_aprintf(int x, int y, VuiAttr a, const char *fmt, ...);