vis: move :-commands into their own file

1 files changed, 1064 insertions, 0 deletions

diff --git a/vis-cmds.c b/vis-cmds.c
new file mode 100644
index 0000000..a25c5e9
--- /dev/null
+++ b/vis-cmds.c
@@ -0,0 +1,1064 @@
+#include <stdbool.h>
+#include <string.h>
+#include <strings.h>
+#include <stdio.h>
+#include <limits.h>
+#include <errno.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <ctype.h>
+#include <sys/select.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+
+#include "vis-core.h"
+#include "text-util.h"
+#include "text-motions.h"
+#include "util.h"
+
+enum CmdOpt {          /* option flags for command definitions */
+	CMD_OPT_NONE,  /* no option (default value) */
+	CMD_OPT_FORCE, /* whether the command can be forced by appending '!' */
+	CMD_OPT_ARGS,  /* whether the command line should be parsed in to space
+	                * separated arguments to placed into argv, otherwise argv[1]
+	                * will contain the  remaining command line unmodified */
+};
+
+typedef struct {             /* command definitions for the ':'-prompt */
+	const char *name[3]; /* name and optional alias for the command */
+	/* command logic called with a NULL terminated array of arguments.
+	 * argv[0] will be the command name */
+	bool (*cmd)(Vis*, Filerange*, enum CmdOpt opt, const char *argv[]);
+	enum CmdOpt opt;     /* command option flags */
+} Command;
+
+/** ':'-command implementations */
+/* set various runtime options */
+static bool cmd_set(Vis*, Filerange*, enum CmdOpt, const char *argv[]);
+/* for each argument create a new window and open the corresponding file */
+static bool cmd_open(Vis*, Filerange*, enum CmdOpt, const char *argv[]);
+/* close current window (discard modifications if forced ) and open argv[1],
+ * if no argv[1] is given re-read to current file from disk */
+static bool cmd_edit(Vis*, Filerange*, enum CmdOpt, const char *argv[]);
+/* close the current window, discard modifications if forced */
+static bool cmd_quit(Vis*, Filerange*, enum CmdOpt, const char *argv[]);
+/* close all windows which show current file, discard modifications if forced  */
+static bool cmd_bdelete(Vis*, Filerange*, enum CmdOpt, const char *argv[]);
+/* close all windows, exit editor, discard modifications if forced */
+static bool cmd_qall(Vis*, Filerange*, enum CmdOpt, const char *argv[]);
+/* for each argument try to insert the file content at current cursor postion */
+static bool cmd_read(Vis*, Filerange*, enum CmdOpt, const char *argv[]);
+static bool cmd_substitute(Vis*, Filerange*, enum CmdOpt, const char *argv[]);
+/* if no argument are given, split the current window horizontally,
+ * otherwise open the file */
+static bool cmd_split(Vis*, Filerange*, enum CmdOpt, const char *argv[]);
+/* if no argument are given, split the current window vertically,
+ * otherwise open the file */
+static bool cmd_vsplit(Vis*, Filerange*, enum CmdOpt, const char *argv[]);
+/* create a new empty window and arrange all windows either horizontally or vertically */
+static bool cmd_new(Vis*, Filerange*, enum CmdOpt, const char *argv[]);
+static bool cmd_vnew(Vis*, Filerange*, enum CmdOpt, const char *argv[]);
+/* save the file displayed in the current window and close it */
+static bool cmd_wq(Vis*, Filerange*, enum CmdOpt, const char *argv[]);
+/* save the file displayed in the current window if it was changvis, then close the window */
+static bool cmd_xit(Vis*, Filerange*, enum CmdOpt, const char *argv[]);
+/* save the file displayed in the current window to the name given.
+ * do not change internal filname association. further :w commands
+ * without arguments will still write to the old filename */
+static bool cmd_write(Vis*, Filerange*, enum CmdOpt, const char *argv[]);
+/* save the file displayed in the current window to the name given,
+ * associate the new name with the buffer. further :w commands
+ * without arguments will write to the new filename */
+static bool cmd_saveas(Vis*, Filerange*, enum CmdOpt, const char *argv[]);
+/* filter range through external program argv[1] */
+static bool cmd_filter(Vis*, Filerange*, enum CmdOpt, const char *argv[]);
+/* switch to the previous/next saved state of the text, chronologically */
+static bool cmd_earlier_later(Vis*, Filerange*, enum CmdOpt, const char *argv[]);
+/* dump current key bindings */
+static bool cmd_help(Vis*, Filerange*, enum CmdOpt, const char *argv[]);
+
+/* command recognized at the ':'-prompt. commands are found using a unique
+ * prefix match. that is if a command should be available under an abbreviation
+ * which is a prefix for another command it has to be added as an alias. the
+ * long human readable name should always come first */
+static Command cmds[] = {
+	/* command name / optional alias, function,       options */
+	{ { "bdelete"                  }, cmd_bdelete,    CMD_OPT_FORCE },
+	{ { "edit"                     }, cmd_edit,       CMD_OPT_FORCE },
+	{ { "help"                     }, cmd_help,       CMD_OPT_NONE  },
+	{ { "new"                      }, cmd_new,        CMD_OPT_NONE  },
+	{ { "open"                     }, cmd_open,       CMD_OPT_NONE  },
+	{ { "qall"                     }, cmd_qall,       CMD_OPT_FORCE },
+	{ { "quit", "q"                }, cmd_quit,       CMD_OPT_FORCE },
+	{ { "read",                    }, cmd_read,       CMD_OPT_FORCE },
+	{ { "saveas"                   }, cmd_saveas,     CMD_OPT_FORCE },
+	{ { "set",                     }, cmd_set,        CMD_OPT_ARGS  },
+	{ { "split"                    }, cmd_split,      CMD_OPT_NONE  },
+	{ { "substitute", "s"          }, cmd_substitute, CMD_OPT_NONE  },
+	{ { "vnew"                     }, cmd_vnew,       CMD_OPT_NONE  },
+	{ { "vsplit",                  }, cmd_vsplit,     CMD_OPT_NONE  },
+	{ { "wq",                      }, cmd_wq,         CMD_OPT_FORCE },
+	{ { "write", "w"               }, cmd_write,      CMD_OPT_FORCE },
+	{ { "xit",                     }, cmd_xit,        CMD_OPT_FORCE },
+	{ { "earlier"                  }, cmd_earlier_later, CMD_OPT_NONE },
+	{ { "later"                    }, cmd_earlier_later, CMD_OPT_NONE },
+	{ { "!",                       }, cmd_filter,     CMD_OPT_NONE  },
+	{ /* array terminator */                                        },
+};
+
+
+static void windows_arrange(Vis *vis, enum UiLayout layout) {
+	vis->ui->arrange(vis->ui, layout);
+}
+
+static void tabwidth_set(Vis *vis, int tabwidth) {
+	if (tabwidth < 1 || tabwidth > 8)
+		return;
+	for (Win *win = vis->windows; win; win = win->next)
+		view_tabwidth_set(win->view, tabwidth);
+	vis->tabwidth = tabwidth;
+}
+
+/* parse human-readable boolean value in s. If successful, store the result in
+ * outval and return true. Else return false and leave outval alone. */
+static bool parse_bool(const char *s, bool *outval) {
+	for (const char **t = (const char*[]){"1", "true", "yes", "on", NULL}; *t; t++) {
+		if (!strcasecmp(s, *t)) {
+			*outval = true;
+			return true;
+		}
+	}
+	for (const char **f = (const char*[]){"0", "false", "no", "off", NULL}; *f; f++) {
+		if (!strcasecmp(s, *f)) {
+			*outval = false;
+			return true;
+		}
+	}
+	return false;
+}
+
+static bool cmd_set(Vis *vis, Filerange *range, enum CmdOpt cmdopt, const char *argv[]) {
+
+	typedef struct {
+		const char *names[3];
+		enum {
+			OPTION_TYPE_STRING,
+			OPTION_TYPE_BOOL,
+			OPTION_TYPE_NUMBER,
+		} type;
+		bool optional;
+		int index;
+	} OptionDef;
+
+	enum {
+		OPTION_AUTOINDENT,
+		OPTION_EXPANDTAB,
+		OPTION_TABWIDTH,
+		OPTION_SYNTAX,
+		OPTION_SHOW,
+		OPTION_NUMBER,
+		OPTION_NUMBER_RELATIVE,
+	};
+
+	/* definitions have to be in the same order as the enum above */
+	static OptionDef options[] = {
+		[OPTION_AUTOINDENT]      = { { "autoindent", "ai"       }, OPTION_TYPE_BOOL   },
+		[OPTION_EXPANDTAB]       = { { "expandtab", "et"        }, OPTION_TYPE_BOOL   },
+		[OPTION_TABWIDTH]        = { { "tabwidth", "tw"         }, OPTION_TYPE_NUMBER },
+		[OPTION_SYNTAX]          = { { "syntax"                 }, OPTION_TYPE_STRING, true },
+		[OPTION_SHOW]            = { { "show"                   }, OPTION_TYPE_STRING },
+		[OPTION_NUMBER]          = { { "numbers", "nu"          }, OPTION_TYPE_BOOL   },
+		[OPTION_NUMBER_RELATIVE] = { { "relativenumbers", "rnu" }, OPTION_TYPE_BOOL   },
+	};
+
+	if (!vis->options) {
+		if (!(vis->options = map_new()))
+			return false;
+		for (int i = 0; i < LENGTH(options); i++) {
+			options[i].index = i;
+			for (const char **name = options[i].names; *name; name++) {
+				if (!map_put(vis->options, *name, &options[i]))
+					return false;
+			}
+		}
+	}
+
+	if (!argv[1]) {
+		vis_info_show(vis, "Expecting: set option [value]");
+		return false;
+	}
+
+	Arg arg;
+	bool invert = false;
+	OptionDef *opt = NULL;
+
+	if (!strncasecmp(argv[1], "no", 2)) {
+		opt = map_closest(vis->options, argv[1]+2);
+		if (opt && opt->type == OPTION_TYPE_BOOL)
+			invert = true;
+		else
+			opt = NULL;
+	}
+
+	if (!opt)
+		opt = map_closest(vis->options, argv[1]);
+	if (!opt) {
+		vis_info_show(vis, "Unknown option: `%s'", argv[1]);
+		return false;
+	}
+
+	switch (opt->type) {
+	case OPTION_TYPE_STRING:
+		if (!opt->optional && !argv[2]) {
+			vis_info_show(vis, "Expecting string option value");
+			return false;
+		}
+		break;
+	case OPTION_TYPE_BOOL:
+		if (!argv[2]) {
+			arg.b = true;
+		} else if (!parse_bool(argv[2], &arg.b)) {
+			vis_info_show(vis, "Expecting boolean option value not: `%s'", argv[2]);
+			return false;
+		}
+		if (invert)
+			arg.b = !arg.b;
+		break;
+	case OPTION_TYPE_NUMBER:
+		if (!argv[2]) {
+			vis_info_show(vis, "Expecting number");
+			return false;
+		}
+		/* TODO: error checking? long type */
+		arg.i = strtoul(argv[2], NULL, 10);
+		break;
+	}
+
+	switch (opt->index) {
+	case OPTION_EXPANDTAB:
+		vis->expandtab = arg.b;
+		break;
+	case OPTION_AUTOINDENT:
+		vis->autoindent = arg.b;
+		break;
+	case OPTION_TABWIDTH:
+		tabwidth_set(vis, arg.i);
+		break;
+	case OPTION_SYNTAX:
+		if (!argv[2]) {
+			Syntax *syntax = view_syntax_get(vis->win->view);
+			if (syntax)
+				vis_info_show(vis, "Syntax definition in use: `%s'", syntax->name);
+			else
+				vis_info_show(vis, "No syntax definition in use");
+			return true;
+		}
+
+		for (Syntax *syntax = vis->syntaxes; syntax && syntax->name; syntax++) {
+			if (!strcasecmp(syntax->name, argv[2])) {
+				view_syntax_set(vis->win->view, syntax);
+				return true;
+			}
+		}
+
+		if (parse_bool(argv[2], &arg.b) && !arg.b)
+			view_syntax_set(vis->win->view, NULL);
+		else
+			vis_info_show(vis, "Unknown syntax definition: `%s'", argv[2]);
+		break;
+	case OPTION_SHOW:
+		if (!argv[2]) {
+			vis_info_show(vis, "Expecting: spaces, tabs, newlines");
+			return false;
+		}
+		char *keys[] = { "spaces", "tabs", "newlines" };
+		int values[] = {
+			UI_OPTION_SYMBOL_SPACE,
+			UI_OPTION_SYMBOL_TAB|UI_OPTION_SYMBOL_TAB_FILL,
+			UI_OPTION_SYMBOL_EOL,
+		};
+		int flags = view_options_get(vis->win->view);
+		for (const char **args = &argv[2]; *args; args++) {
+			for (int i = 0; i < LENGTH(keys); i++) {
+				if (strcmp(*args, keys[i]) == 0) {
+					flags |= values[i];
+				} else if (strstr(*args, keys[i]) == *args) {
+					bool show;
+					const char *v = *args + strlen(keys[i]);
+					if (*v == '=' && parse_bool(v+1, &show)) {
+						if (show)
+							flags |= values[i];
+						else
+							flags &= ~values[i];
+					}
+				}
+			}
+		}
+		view_options_set(vis->win->view, flags);
+		break;
+	case OPTION_NUMBER: {
+		enum UiOption opt = view_options_get(vis->win->view);
+		if (arg.b) {
+			opt &= ~UI_OPTION_LINE_NUMBERS_RELATIVE;
+			opt |=  UI_OPTION_LINE_NUMBERS_ABSOLUTE;
+		} else {
+			opt &= ~UI_OPTION_LINE_NUMBERS_ABSOLUTE;
+		}
+		view_options_set(vis->win->view, opt); 
+		break;
+	}
+	case OPTION_NUMBER_RELATIVE: {
+		enum UiOption opt = view_options_get(vis->win->view);
+		if (arg.b) {
+			opt &= ~UI_OPTION_LINE_NUMBERS_ABSOLUTE;
+			opt |=  UI_OPTION_LINE_NUMBERS_RELATIVE;
+		} else {
+			opt &= ~UI_OPTION_LINE_NUMBERS_RELATIVE;
+		}
+		view_options_set(vis->win->view, opt); 
+		break;
+	}
+	}
+
+	return true;
+}
+
+static bool is_file_pattern(const char *pattern) {
+	return pattern && (strcmp(pattern, ".") == 0 || strchr(pattern, '*') ||
+	       strchr(pattern, '[') || strchr(pattern, '{'));
+}
+
+static const char *file_open_dialog(Vis *vis, const char *pattern) {
+	if (!is_file_pattern(pattern))
+		return pattern;
+	/* this is a bit of a hack, we temporarily replace the text/view of the active
+	 * window such that we can use cmd_filter as is */
+	char vis_open[512];
+	static char filename[PATH_MAX];
+	Filerange range = text_range_empty();
+	Win *win = vis->win;
+	File *file = win->file;
+	Text *txt_orig = file->text;
+	View *view_orig = win->view;
+	Text *txt = text_load(NULL);
+	View *view = view_new(txt, NULL);
+	filename[0] = '\0';
+	snprintf(vis_open, sizeof(vis_open)-1, "vis-open %s", pattern ? pattern : "");
+
+	if (!txt || !view)
+		goto out;
+	win->view = view;
+	file->text = txt;
+
+	if (cmd_filter(vis, &range, CMD_OPT_NONE, (const char *[]){ "open", vis_open, NULL })) {
+		size_t len = text_size(txt);
+		if (len >= sizeof(filename))
+			len = 0;
+		if (len > 0)
+			text_bytes_get(txt, 0, --len, filename);
+		filename[len] = '\0';
+	}
+
+out:
+	view_free(view);
+	text_free(txt);
+	win->view = view_orig;
+	file->text = txt_orig;
+	return filename[0] ? filename : NULL;
+}
+
+static bool openfiles(Vis *vis, const char **files) {
+	for (; *files; files++) {
+		const char *file = file_open_dialog(vis, *files);
+		if (!file)
+			return false;
+		errno = 0;
+		if (!vis_window_new(vis, file)) {
+			vis_info_show(vis, "Could not open `%s' %s", file,
+			                 errno ? strerror(errno) : "");
+			return false;
+		}
+	}
+	return true;
+}
+
+static bool cmd_open(Vis *vis, Filerange *range, enum CmdOpt opt, const char *argv[]) {
+	if (!argv[1])
+		return vis_window_new(vis, NULL);
+	return openfiles(vis, &argv[1]);
+}
+
+static bool is_view_closeable(Win *win) {
+	if (!text_modified(win->file->text))
+		return true;
+	return win->file->refcount > 1;
+}
+
+static void info_unsaved_changes(Vis *vis) {
+	vis_info_show(vis, "No write since last change (add ! to override)");
+}
+
+static bool cmd_edit(Vis *vis, Filerange *range, enum CmdOpt opt, const char *argv[]) {
+	Win *oldwin = vis->win;
+	if (!(opt & CMD_OPT_FORCE) && !is_view_closeable(oldwin)) {
+		info_unsaved_changes(vis);
+		return false;
+	}
+	if (!argv[1])
+		return vis_window_reload(oldwin);
+	if (!openfiles(vis, &argv[1]))
+		return false;
+	if (vis->win != oldwin)
+		vis_window_close(oldwin);
+	return vis->win != oldwin;
+}
+
+static bool cmd_quit(Vis *vis, Filerange *range, enum CmdOpt opt, const char *argv[]) {
+	if (!(opt & CMD_OPT_FORCE) && !is_view_closeable(vis->win)) {
+		info_unsaved_changes(vis);
+		return false;
+	}
+	vis_window_close(vis->win);
+	if (!vis->windows)
+		vis_exit(vis, EXIT_SUCCESS);
+	return true;
+}
+
+static bool cmd_xit(Vis *vis, Filerange *range, enum CmdOpt opt, const char *argv[]) {
+	if (text_modified(vis->win->file->text) && !cmd_write(vis, range, opt, argv)) {
+		if (!(opt & CMD_OPT_FORCE))
+			return false;
+	}
+	return cmd_quit(vis, range, opt, argv);
+}
+
+static bool cmd_bdelete(Vis *vis, Filerange *range, enum CmdOpt opt, const char *argv[]) {
+	Text *txt = vis->win->file->text;
+	if (text_modified(txt) && !(opt & CMD_OPT_FORCE)) {
+		info_unsaved_changes(vis);
+		return false;
+	}
+	for (Win *next, *win = vis->windows; win; win = next) {
+		next = win->next;
+		if (win->file->text == txt)
+			vis_window_close(win);
+	}
+	if (!vis->windows)
+		vis_exit(vis, EXIT_SUCCESS);
+	return true;
+}
+
+static bool cmd_qall(Vis *vis, Filerange *range, enum CmdOpt opt, const char *argv[]) {
+	for (Win *next, *win = vis->windows; win; win = next) {
+		next = win->next;
+		if (!text_modified(vis->win->file->text) || (opt & CMD_OPT_FORCE))
+			vis_window_close(win);
+	}
+	if (!vis->windows)
+		vis_exit(vis, EXIT_SUCCESS);
+	else
+		info_unsaved_changes(vis);
+	return vis->windows == NULL;
+}
+
+static bool cmd_read(Vis *vis, Filerange *range, enum CmdOpt opt, const char *argv[]) {
+	char cmd[255];
+
+	if (!argv[1]) {
+		vis_info_show(vis, "Filename or command expected");
+		return false;
+	}
+
+	bool iscmd = (opt & CMD_OPT_FORCE) || argv[1][0] == '!';
+	const char *arg = argv[1]+(argv[1][0] == '!');
+	snprintf(cmd, sizeof cmd, "%s%s", iscmd ? "" : "cat ", arg);
+
+	size_t pos = view_cursor_get(vis->win->view);
+	if (!text_range_valid(range))
+		*range = (Filerange){ .start = pos, .end = pos };
+	Filerange delete = *range;
+	range->start = range->end;
+
+	bool ret = cmd_filter(vis, range, opt, (const char*[]){ argv[0], "sh", "-c", cmd, NULL});
+	if (ret)
+		text_delete_range(vis->win->file->text, &delete);
+	return ret;
+}
+
+static bool cmd_substitute(Vis *vis, Filerange *range, enum CmdOpt opt, const char *argv[]) {
+	char pattern[255];
+	if (!text_range_valid(range))
+		*range = (Filerange){ .start = 0, .end = text_size(vis->win->file->text) };
+	snprintf(pattern, sizeof pattern, "s%s", argv[1]);
+	return cmd_filter(vis, range, opt, (const char*[]){ argv[0], "sed", pattern, NULL});
+}
+
+static bool cmd_split(Vis *vis, Filerange *range, enum CmdOpt opt, const char *argv[]) {
+	enum UiOption options = view_options_get(vis->win->view);
+	windows_arrange(vis, UI_LAYOUT_HORIZONTAL);
+	if (!argv[1])
+		return vis_window_split(vis->win);
+	bool ret = openfiles(vis, &argv[1]);
+	view_options_set(vis->win->view, options);
+	return ret;
+}
+
+static bool cmd_vsplit(Vis *vis, Filerange *range, enum CmdOpt opt, const char *argv[]) {
+	enum UiOption options = view_options_get(vis->win->view);
+	windows_arrange(vis, UI_LAYOUT_VERTICAL);
+	if (!argv[1])
+		return vis_window_split(vis->win);
+	bool ret = openfiles(vis, &argv[1]);
+	view_options_set(vis->win->view, options);
+	return ret;
+}
+
+static bool cmd_new(Vis *vis, Filerange *range, enum CmdOpt opt, const char *argv[]) {
+	windows_arrange(vis, UI_LAYOUT_HORIZONTAL);
+	return vis_window_new(vis, NULL);
+}
+
+static bool cmd_vnew(Vis *vis, Filerange *range, enum CmdOpt opt, const char *argv[]) {
+	windows_arrange(vis, UI_LAYOUT_VERTICAL);
+	return vis_window_new(vis, NULL);
+}
+
+static bool cmd_wq(Vis *vis, Filerange *range, enum CmdOpt opt, const char *argv[]) {
+	if (cmd_write(vis, range, opt, argv))
+		return cmd_quit(vis, range, opt, argv);
+	return false;
+}
+
+static bool cmd_write(Vis *vis, Filerange *range, enum CmdOpt opt, const char *argv[]) {
+	File *file = vis->win->file;
+	Text *text = file->text;
+	if (!text_range_valid(range))
+		*range = (Filerange){ .start = 0, .end = text_size(text) };
+	if (!argv[1])
+		argv[1] = file->name;
+	if (!argv[1]) {
+		if (file->is_stdin) {
+			if (strchr(argv[0], 'q')) {
+				ssize_t written = text_write_range(text, range, STDOUT_FILENO);
+				if (written == -1 || (size_t)written != text_range_size(range)) {
+					vis_info_show(vis, "Can not write to stdout");
+					return false;
+				}
+				/* make sure the file is marked as saved i.e. not modified */
+				text_save_range(text, range, NULL);
+				return true;
+			}
+			vis_info_show(vis, "No filename given, use 'wq' to write to stdout");
+			return false;
+		}
+		vis_info_show(vis, "Filename expected");
+		return false;
+	}
+	for (const char **name = &argv[1]; *name; name++) {
+		struct stat meta;
+		if (!(opt & CMD_OPT_FORCE) && file->stat.st_mtime && stat(*name, &meta) == 0 &&
+		    file->stat.st_mtime < meta.st_mtime) {
+			vis_info_show(vis, "WARNING: file has been changed since reading it");
+			return false;
+		}
+		if (!text_save_range(text, range, *name)) {
+			vis_info_show(vis, "Can't write `%s'", *name);
+			return false;
+		}
+		if (!file->name) {
+			vis_window_name(vis->win, *name);
+			file->name = vis->win->file->name;
+		}
+		if (strcmp(file->name, *name) == 0)
+			file->stat = text_stat(text);
+	}
+	return true;
+}
+
+static bool cmd_saveas(Vis *vis, Filerange *range, enum CmdOpt opt, const char *argv[]) {
+	if (cmd_write(vis, range, opt, argv)) {
+		vis_window_name(vis->win, argv[1]);
+		vis->win->file->stat = text_stat(vis->win->file->text);
+		return true;
+	}
+	return false;
+}
+
+static bool cmd_filter(Vis *vis, Filerange *range, enum CmdOpt opt, const char *argv[]) {
+	/* if an invalid range was given, stdin (i.e. key board input) is passed
+	 * through the external command. */
+	Text *text = vis->win->file->text;
+	View *view = vis->win->view;
+	int pin[2], pout[2], perr[2], status = -1;
+	bool interactive = !text_range_valid(range);
+	size_t pos = view_cursor_get(view);
+
+	if (pipe(pin) == -1)
+		return false;
+	if (pipe(pout) == -1) {
+		close(pin[0]);
+		close(pin[1]);
+		return false;
+	}
+
+	if (pipe(perr) == -1) {
+		close(pin[0]);
+		close(pin[1]);
+		close(pout[0]);
+		close(pout[1]);
+		return false;
+	}
+
+	vis->ui->terminal_save(vis->ui);
+	pid_t pid = fork();
+
+	if (pid == -1) {
+		close(pin[0]);
+		close(pin[1]);
+		close(pout[0]);
+		close(pout[1]);
+		close(perr[0]);
+		close(perr[1]);
+		vis_info_show(vis, "fork failure: %s", strerror(errno));
+		return false;
+	} else if (pid == 0) { /* child i.e filter */
+		if (!interactive)
+			dup2(pin[0], STDIN_FILENO);
+		close(pin[0]);
+		close(pin[1]);
+		dup2(pout[1], STDOUT_FILENO);
+		close(pout[1]);
+		close(pout[0]);
+		if (!interactive)
+			dup2(perr[1], STDERR_FILENO);
+		close(perr[0]);
+		close(perr[1]);
+		if (!argv[2])
+			execl("/bin/sh", "sh", "-c", argv[1], NULL);
+		else
+			execvp(argv[1], (char**)argv+1);
+		vis_info_show(vis, "exec failure: %s", strerror(errno));
+		exit(EXIT_FAILURE);
+	}
+
+	vis->cancel_filter = false;
+
+	close(pin[0]);
+	close(pout[1]);
+	close(perr[1]);
+
+	fcntl(pout[0], F_SETFL, O_NONBLOCK);
+	fcntl(perr[0], F_SETFL, O_NONBLOCK);
+
+	if (interactive)
+		*range = (Filerange){ .start = pos, .end = pos };
+
+	/* ranges which are written to the filter and read back in */
+	Filerange rout = *range;
+	Filerange rin = (Filerange){ .start = range->end, .end = range->end };
+
+	/* The general idea is the following:
+	 *
+	 *  1) take a snapshot
+	 *  2) write [range.start, range.end] to exteneral command
+	 *  3) read the output of the external command and insert it after the range
+	 *  4) depending on the exit status of the external command
+	 *     - on success: delete original range
+	 *     - on failure: revert to previous snapshot
+	 *
+	 *  2) and 3) happend in small junks
+	 */
+
+	text_snapshot(text);
+
+	fd_set rfds, wfds;
+	Buffer errmsg;
+	buffer_init(&errmsg);
+
+	do {
+		if (vis->cancel_filter) {
+			kill(-pid, SIGTERM);
+			vis_info_show(vis, "Command cancelled");
+			break;
+		}
+
+		FD_ZERO(&rfds);
+		FD_ZERO(&wfds);
+		if (pin[1] != -1)
+			FD_SET(pin[1], &wfds);
+		if (pout[0] != -1)
+			FD_SET(pout[0], &rfds);
+		if (perr[0] != -1)
+			FD_SET(perr[0], &rfds);
+
+		if (select(FD_SETSIZE, &rfds, &wfds, NULL, NULL) == -1) {
+			if (errno == EINTR)
+				continue;
+			vis_info_show(vis, "Select failure");
+			break;
+		}
+
+		if (pin[1] != -1 && FD_ISSET(pin[1], &wfds)) {
+			Filerange junk = *range;
+			if (junk.end > junk.start + PIPE_BUF)
+				junk.end = junk.start + PIPE_BUF;
+			ssize_t len = text_write_range(text, &junk, pin[1]);
+			if (len > 0) {
+				range->start += len;
+				if (text_range_size(range) == 0) {
+					close(pout[1]);
+					pout[1] = -1;
+				}
+			} else {
+				close(pin[1]);
+				pin[1] = -1;
+				if (len == -1)
+					vis_info_show(vis, "Error writing to external command");
+			}
+		}
+
+		if (pout[0] != -1 && FD_ISSET(pout[0], &rfds)) {
+			char buf[BUFSIZ];
+			ssize_t len = read(pout[0], buf, sizeof buf);
+			if (len > 0) {
+				text_insert(text, rin.end, buf, len);
+				rin.end += len;
+			} else if (len == 0) {
+				close(pout[0]);
+				pout[0] = -1;
+			} else if (errno != EINTR && errno != EWOULDBLOCK) {
+				vis_info_show(vis, "Error reading from filter stdout");
+				close(pout[0]);
+				pout[0] = -1;
+			}
+		}
+
+		if (perr[0] != -1 && FD_ISSET(perr[0], &rfds)) {
+			char buf[BUFSIZ];
+			ssize_t len = read(perr[0], buf, sizeof buf);
+			if (len > 0) {
+				buffer_append(&errmsg, buf, len);
+			} else if (len == 0) {
+				close(perr[0]);
+				perr[0] = -1;
+			} else if (errno != EINTR && errno != EWOULDBLOCK) {
+				vis_info_show(vis, "Error reading from filter stderr");
+				close(pout[0]);
+				pout[0] = -1;
+			}
+		}
+
+	} while (pin[1] != -1 || pout[0] != -1 || perr[0] != -1);
+
+	if (pin[1] != -1)
+		close(pin[1]);
+	if (pout[0] != -1)
+		close(pout[0]);
+	if (perr[0] != -1)
+		close(perr[0]);
+
+	if (waitpid(pid, &status, 0) == pid && status == 0) {
+		text_delete_range(text, &rout);
+		text_snapshot(text);
+	} else {
+		/* make sure we have somehting to undo */
+		text_insert(text, pos, " ", 1);
+		text_undo(text);
+	}
+
+	view_cursor_to(view, rout.start);
+
+	if (!vis->cancel_filter) {
+		if (status == 0)
+			vis_info_show(vis, "Command succeded");
+		else if (errmsg.len > 0)
+			vis_info_show(vis, "Command failed: %s", errmsg.data);
+		else
+			vis_info_show(vis, "Command failed");
+	}
+
+	vis->ui->terminal_restore(vis->ui);
+	return status == 0;
+}
+
+static bool cmd_earlier_later(Vis *vis, Filerange *range, enum CmdOpt opt, const char *argv[]) {
+	Text *txt = vis->win->file->text;
+	char *unit = "";
+	long count = 1;
+	size_t pos = EPOS;
+	if (argv[1]) {
+		errno = 0;
+		count = strtol(argv[1], &unit, 10);
+		if (errno || unit == argv[1] || count < 0) {
+			vis_info_show(vis, "Invalid number");
+			return false;
+		}
+
+		if (*unit) {
+			while (*unit && isspace((unsigned char)*unit))
+				unit++;
+			switch (*unit) {
+			case 'd': count *= 24; /* fall through */
+			case 'h': count *= 60; /* fall through */
+			case 'm': count *= 60; /* fall through */
+			case 's': break;
+			default:
+				vis_info_show(vis, "Unknown time specifier (use: s,m,h or d)");
+				return false;
+			}
+
+			if (argv[0][0] == 'e')
+				count = -count; /* earlier, move back in time */
+
+			pos = text_restore(txt, text_state(txt) + count);
+		}
+	}
+
+	if (!*unit) {
+		if (argv[0][0] == 'e')
+			pos = text_earlier(txt, count);
+		else
+			pos = text_later(txt, count);
+	}
+
+	time_t state = text_state(txt);
+	char buf[32];
+	strftime(buf, sizeof buf, "State from %H:%M", localtime(&state));
+	vis_info_show(vis, "%s", buf);
+
+	return pos != EPOS;
+}
+
+bool print_keybinding(const char *key, void *value, void *data) {
+	Text *txt = (Text*)data;
+	KeyBinding *binding = (KeyBinding*)value;
+	const char *desc = binding->alias;
+	if (!desc && binding->action)
+		desc = binding->action->help;
+	return text_appendf(txt, "  %-15s\t%s\n", key, desc ? desc : "");
+}
+
+static void print_mode(Mode *mode, Text *txt, bool recursive) {
+	if (recursive && mode->parent)
+		print_mode(mode->parent, txt, recursive);
+	map_iterate(mode->bindings, print_keybinding, txt);
+}
+
+static bool cmd_help(Vis *vis, Filerange *range, enum CmdOpt opt, const char *argv[]) {
+	if (!vis_window_new(vis, NULL))
+		return false;
+	
+	Text *txt = vis->win->file->text;
+
+	text_appendf(txt, "vis %s, compiled " __DATE__ " " __TIME__ "\n\n", VERSION);
+
+	text_appendf(txt, " Modes\n\n");
+	for (int i = 0; i < LENGTH(vis_modes); i++) {
+		Mode *mode = &vis_modes[i];
+		if (mode->help)
+			text_appendf(txt, "  %-15s\t%s\n", mode->name, mode->help);
+	}
+
+	for (int i = 0; i < LENGTH(vis_modes); i++) {
+		Mode *mode = &vis_modes[i];
+		if (mode->isuser && !map_empty(mode->bindings)) {
+			text_appendf(txt, "\n %s\n\n", mode->name);
+			print_mode(mode, txt, i == VIS_MODE_NORMAL ||
+				i == VIS_MODE_INSERT);
+		}
+	}
+	
+	text_appendf(txt, "\n Text objects\n\n");
+	print_mode(&vis_modes[VIS_MODE_TEXTOBJ], txt, false);
+
+	text_appendf(txt, "\n Motions\n\n");
+	print_mode(&vis_modes[VIS_MODE_MOVE], txt, false);
+
+	text_appendf(txt, "\n :-Commands\n\n");
+	for (Command *cmd = cmds; cmd && cmd->name[0]; cmd++)
+		text_appendf(txt, "  %s\n", cmd->name[0]);
+
+	text_save(txt, NULL);
+	return true;
+}
+
+static Filepos parse_pos(Win *win, char **cmd) {
+	size_t pos = EPOS;
+	View *view = win->view;
+	Text *txt = win->file->text;
+	Mark *marks = win->file->marks;
+	switch (**cmd) {
+	case '.':
+		pos = text_line_begin(txt, view_cursor_get(view));
+		(*cmd)++;
+		break;
+	case '$':
+		pos = text_size(txt);
+		(*cmd)++;
+		break;
+	case '\'':
+		(*cmd)++;
+		if ('a' <= **cmd && **cmd <= 'z')
+			pos = text_mark_get(txt, marks[**cmd - 'a']);
+		else if (**cmd == '<')
+			pos = text_mark_get(txt, marks[MARK_SELECTION_START]);
+		else if (**cmd == '>')
+			pos = text_mark_get(txt, marks[MARK_SELECTION_END]);
+		(*cmd)++;
+		break;
+	case '/':
+		(*cmd)++;
+		char *pattern_end = strchr(*cmd, '/');
+		if (!pattern_end)
+			return EPOS;
+		*pattern_end++ = '\0';
+		Regex *regex = text_regex_new();
+		if (!regex)
+			return EPOS;
+		if (!text_regex_compile(regex, *cmd, 0)) {
+			*cmd = pattern_end;
+			pos = text_search_forward(txt, view_cursor_get(view), regex);
+		}
+		text_regex_free(regex);
+		break;
+	case '+':
+	case '-':
+	{
+		CursorPos curspos = view_cursor_getpos(view);
+		long long line = curspos.line + strtoll(*cmd, cmd, 10);
+		if (line < 0)
+			line = 0;
+		pos = text_pos_by_lineno(txt, line);
+		break;
+	}
+	default:
+		if ('0' <= **cmd && **cmd <= '9')
+			pos = text_pos_by_lineno(txt, strtoul(*cmd, cmd, 10));
+		break;
+	}
+
+	return pos;
+}
+
+static Filerange parse_range(Win *win, char **cmd) {
+	Text *txt = win->file->text;
+	Filerange r = text_range_empty();
+	Mark *marks = win->file->marks;
+	char start = **cmd;
+	switch (**cmd) {
+	case '%':
+		r.start = 0;
+		r.end = text_size(txt);
+		(*cmd)++;
+		break;
+	case '*':
+		r.start = text_mark_get(txt, marks[MARK_SELECTION_START]);
+		r.end = text_mark_get(txt, marks[MARK_SELECTION_END]);
+		(*cmd)++;
+		break;
+	default:
+		r.start = parse_pos(win, cmd);
+		if (**cmd != ',') {
+			if (start == '.')
+				r.end = text_line_next(txt, r.start);
+			return r;
+		}
+		(*cmd)++;
+		r.end = parse_pos(win, cmd);
+		break;
+	}
+	return r;
+}
+
+static Command *lookup_cmd(Vis *vis, const char *name) {
+	if (!vis->cmds) {
+		if (!(vis->cmds = map_new()))
+			return NULL;
+	
+		for (Command *cmd = cmds; cmd && cmd->name[0]; cmd++) {
+			for (const char **name = cmd->name; *name; name++)
+				map_put(vis->cmds, *name, cmd);
+		}
+	}
+	return map_closest(vis->cmds, name);
+}
+
+bool vis_cmd(Vis *vis, const char *cmdline) {
+	enum CmdOpt opt = CMD_OPT_NONE;
+	size_t len = strlen(cmdline);
+	char *line = malloc(len+2);
+	if (!line)
+		return false;
+	line = strncpy(line, cmdline, len+1);
+	char *name = line;
+
+	Filerange range = parse_range(vis->win, &name);
+	if (!text_range_valid(&range)) {
+		/* if only one position was given, jump to it */
+		if (range.start != EPOS && !*name) {
+			view_cursor_to(vis->win->view, range.start);
+			free(line);
+			return true;
+		}
+
+		if (name != line) {
+			vis_info_show(vis, "Invalid range\n");
+			free(line);
+			return false;
+		}
+	}
+	/* skip leading white space */
+	while (*name == ' ')
+		name++;
+	char *param = name;
+	while (*param && isalpha(*param))
+		param++;
+
+	if (*param == '!') {
+		if (param != name) {
+			opt |= CMD_OPT_FORCE;
+			*param = ' ';
+		} else {
+			param++;
+		}
+	}
+
+	memmove(param+1, param, strlen(param)+1);
+	*param++ = '\0'; /* separate command name from parameters */
+
+	Command *cmd = lookup_cmd(vis, name);
+	if (!cmd) {
+		vis_info_show(vis, "Not an editor command");
+		free(line);
+		return false;
+	}
+
+	char *s = param;
+	const char *argv[32] = { name };
+	for (int i = 1; i < LENGTH(argv); i++) {
+		while (s && *s && *s == ' ')
+			s++;
+		if (s && !*s)
+			s = NULL;
+		argv[i] = s;
+		if (!(cmd->opt & CMD_OPT_ARGS)) {
+			/* remove trailing spaces */
+			if (s) {
+				while (*s) s++;
+				while (*(--s) == ' ') *s = '\0';
+			}
+			s = NULL;
+		}
+		if (s && (s = strchr(s, ' ')))
+			*s++ = '\0';
+		/* strip out a single '!' argument to make ":q !" work */
+		if (argv[i] && !strcmp(argv[i], "!")) {
+			opt |= CMD_OPT_FORCE;
+			i--;
+		}
+	}
+
+	cmd->cmd(vis, &range, opt, argv);
+	free(line);
+	return true;
+}