1 files changed, 171 insertions, 0 deletions
diff --git a/src/goto-commands.c b/src/goto-commands.c
new file mode 100644
index 0000000..792b4e3
--- /dev/null
+++ b/src/goto-commands.c
@@ -0,0 +1,171 @@
+/*
+ * Copyright (C) 2012-2021 Robin Haberkorn
+ *
+ * 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 <http://www.gnu.org/licenses/>.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <string.h>
+
+#include <glib.h>
+
+#include "sciteco.h"
+#include "string-utils.h"
+#include "expressions.h"
+#include "parser.h"
+#include "core-commands.h"
+#include "undo.h"
+#include "goto.h"
+#include "goto-commands.h"
+
+teco_string_t teco_goto_skip_label = {NULL, 0};
+
+static gboolean
+teco_state_label_initial(teco_machine_main_t *ctx, GError **error)
+{
+	memset(&ctx->goto_label, 0, sizeof(ctx->goto_label));
+	return TRUE;
+}
+
+/*
+ * NOTE: The comma is theoretically not allowed in a label
+ * (see <O> syntax), but is accepted anyway since labels
+ * are historically used as comments.
+ *
+ * TODO: Add support for "true" comments of the form !* ... *!
+ * This would be almost trivial to implement, but if we don't
+ * want any (even temporary) overhead for comments at all, we need
+ * to add a new parser state.
+ * I'm unsure whether !-signs should be allowed within comments.
+ */
+static teco_state_t *
+teco_state_label_input(teco_machine_main_t *ctx, gchar chr, GError **error)
+{
+	if (chr == '!') {
+		/*
+		 * NOTE: If the label already existed, its PC will be restored
+		 * on rubout.
+		 * Otherwise, the label will be removed (PC == -1).
+		 */
+		gint existing_pc = teco_goto_table_set(&ctx->goto_table, ctx->goto_label.data,
+		                                       ctx->goto_label.len, ctx->macro_pc);
+		if (ctx->parent.must_undo)
+			teco_goto_table_undo_set(&ctx->goto_table, ctx->goto_label.data, ctx->goto_label.len, existing_pc);
+
+		if (teco_goto_skip_label.len > 0 &&
+		    !teco_string_cmp(&ctx->goto_label, teco_goto_skip_label.data, teco_goto_skip_label.len)) {
+			teco_undo_string_own(teco_goto_skip_label);
+			memset(&teco_goto_skip_label, 0, sizeof(teco_goto_skip_label));
+
+			if (ctx->parent.must_undo)
+				teco_undo_guint(ctx->__flags);
+			ctx->mode = TECO_MODE_NORMAL;
+		}
+
+		if (ctx->parent.must_undo)
+			teco_undo_string_own(ctx->goto_label);
+		else
+			teco_string_clear(&ctx->goto_label);
+		return &teco_state_start;
+	}
+
+	if (ctx->parent.must_undo)
+		undo__teco_string_truncate(&ctx->goto_label, ctx->goto_label.len);
+	teco_string_append_c(&ctx->goto_label, chr);
+	return &teco_state_label;
+}
+
+TECO_DEFINE_STATE(teco_state_label,
+	.initial_cb = (teco_state_initial_cb_t)teco_state_label_initial
+);
+
+static teco_state_t *
+teco_state_goto_done(teco_machine_main_t *ctx, const teco_string_t *str, GError **error)
+{
+	if (ctx->mode > TECO_MODE_NORMAL)
+		return &teco_state_start;
+
+	teco_int_t value;
+	if (!teco_expressions_pop_num_calc(&value, 1, error))
+		return NULL;
+
+	/*
+	 * Find the comma-separated substring in str indexed by `value`.
+	 */
+	teco_string_t label = {NULL, 0};
+	while (value > 0) {
+		label.data = label.data ? label.data+label.len+1 : str->data;
+		const gchar *p = memchr(label.data, ',', str->len - (label.data - str->data));
+		label.len = p ? p - label.data : str->len - (label.data - str->data);
+
+		value--;
+
+		if (!p)
+			break;
+	}
+
+	if (value == 0) {
+		gint pc = teco_goto_table_find(&ctx->goto_table, label.data, label.len);
+
+		if (pc >= 0) {
+			ctx->macro_pc = pc;
+		} else {
+			/* skip till label is defined */
+			g_assert(teco_goto_skip_label.len == 0);
+			undo__teco_string_truncate(&teco_goto_skip_label, 0);
+			teco_string_init(&teco_goto_skip_label, label.data, label.len);
+			if (ctx->parent.must_undo)
+				teco_undo_guint(ctx->__flags);
+			ctx->mode = TECO_MODE_PARSE_ONLY_GOTO;
+		}
+	}
+
+	return &teco_state_start;
+}
+
+/* in cmdline.c */
+gboolean teco_state_goto_process_edit_cmd(teco_machine_main_t *ctx, teco_machine_t *parent_ctx, gchar chr, GError **error);
+
+/*$ O
+ * Olabel$ -- Go to label
+ * [n]Olabel1[,label2,...]$
+ *
+ * Go to <label>.
+ * The simple go-to command is a special case of the
+ * computed go-to command.
+ * A comma-separated list of labels may be specified
+ * in the string argument.
+ * The label to jump to is selected by <n> (1 is <label1>,
+ * 2 is <label2>, etc.).
+ * If <n> is omitted, 1 is implied.
+ *
+ * If the label selected by <n> is does not exist in the
+ * list of labels, the command does nothing.
+ * Label definitions are cached in a table, so that
+ * if the label to go to has already been defined, the
+ * go-to command will jump immediately.
+ * Otherwise, parsing continues until the <label>
+ * is defined.
+ * The command will yield an error if a label has
+ * not been defined when the macro or command-line
+ * is terminated.
+ * In the latter case, the user will not be able to
+ * terminate the command-line.
+ */
+TECO_DEFINE_STATE_EXPECTSTRING(teco_state_goto,
+	.process_edit_cmd_cb = (teco_state_process_edit_cmd_cb_t)teco_state_goto_process_edit_cmd
+);