vis: add motions [[, [], ][, ]]

They behave not like in vim, but instead try to find the
start/end of C-like function definitions.

The first character stands for the direction [ for backwards,
] for forwards. The second character denotes the start [ or
end ] respectively.

4 files changed, 127 insertions, 0 deletions

diff --git a/config.def.h b/config.def.h
index 1a3a24c..910e1e7 100644
--- a/config.def.h
+++ b/config.def.h
@@ -123,6 +123,10 @@ static KeyBinding vis_movements[] = {
 	{ { NONE('}')               }, movement,     { .i = MOVE_PARAGRAPH_NEXT      } },
 	{ { NONE('(')               }, movement,     { .i = MOVE_SENTENCE_PREV       } },
 	{ { NONE(')')               }, movement,     { .i = MOVE_SENTENCE_NEXT       } },
+	{ { NONE('['), NONE('[')    }, movement,     { .i = MOVE_FUNCTION_START_PREV } },
+	{ { NONE('['), NONE(']')    }, movement,     { .i = MOVE_FUNCTION_END_PREV   } },
+	{ { NONE(']'), NONE('[')    }, movement,     { .i = MOVE_FUNCTION_START_NEXT } },
+	{ { NONE(']'), NONE(']')    }, movement,     { .i = MOVE_FUNCTION_END_NEXT   } },
 	{ { NONE('g'), NONE('g')    }, gotoline,     { .i = -1                       } },
 	{ { NONE('g'), NONE('0')    }, movement,     { .i = MOVE_SCREEN_LINE_BEGIN   } },
 	{ { NONE('g'), NONE('m')    }, movement,     { .i = MOVE_SCREEN_LINE_MIDDLE  } },
diff --git a/text-motions.c b/text-motions.c
index 8b349c2..306e54c 100644
--- a/text-motions.c
+++ b/text-motions.c
@@ -421,6 +421,113 @@ size_t text_paragraph_prev(Text *txt, size_t pos) {
 	return text_paragraph_sentence_prev(txt, pos, false);
 }
 
+size_t text_line_empty_next(Text *txt, size_t pos) {
+	// TODO refactor search \n\n
+	char c;
+	Iterator it = text_iterator_get(txt, pos);
+	while (text_iterator_byte_get(&it, &c)) {
+		if (c == '\n' && text_iterator_byte_next(&it, &c)) {
+			size_t match = it.pos;
+			if (c == '\r')
+				text_iterator_byte_next(&it, &c);
+			if (c == '\n')
+				return match;
+		}
+		text_iterator_byte_next(&it, NULL);
+	}
+	return pos;
+}
+
+size_t text_line_empty_prev(Text *txt, size_t pos) {
+	// TODO refactor search \n\n
+	char c;
+	Iterator it = text_iterator_get(txt, pos);
+	while (text_iterator_byte_prev(&it, &c)) {
+		if (c == '\n' && text_iterator_byte_prev(&it, &c)) {
+			if (c == '\r')
+				text_iterator_byte_prev(&it, &c);
+			if (c == '\n')
+				return it.pos + 1;
+		}
+	}
+	return pos;
+}
+
+size_t text_function_start_next(Text *txt, size_t pos) {
+	size_t a = text_function_end_next(txt, pos);
+	size_t b = a;
+	char c;
+	if (a != pos) {
+		Iterator it = text_iterator_get(txt, a);
+		while (text_iterator_byte_next(&it, &c) && (c == '\r' || c == '\n'));
+		a = it.pos;
+	}
+	if (b != pos) {
+		size_t match = text_bracket_match(txt, b);
+		b = match != b ? text_line_next(txt, text_line_empty_prev(txt, match)) : pos;
+	}
+	if (a <= pos && b <= pos)
+		return pos;
+	else if (a <= pos)
+		return b;
+	else if (b <= pos)
+		return a;
+	else
+		return MIN(a, b);
+}
+
+size_t text_function_start_prev(Text *txt, size_t pos) {
+	char c;
+	size_t apos = text_byte_get(txt, pos, &c) && c == '}' && pos > 0 ? pos - 1 : pos;
+	size_t a = text_function_end_next(txt, apos);
+	size_t b = text_function_end_prev(txt, pos);
+	if (a != apos) {
+		size_t match = text_bracket_match(txt, a);
+		a = match != a ? text_line_next(txt, text_line_empty_prev(txt, match)) : pos;
+	}
+	if (b != pos) {
+		size_t match = text_bracket_match(txt, b);
+		b = match != b ? text_line_next(txt, text_line_empty_prev(txt, match)) : pos;
+	}
+	if (a >= pos && b >= pos)
+		return pos;
+	else if (a >= pos)
+		return b;
+	else if (b >= pos)
+		return a;
+	else
+		return MAX(a, b);
+}
+
+static size_t text_function_end_direction(Text *txt, size_t pos, int direction) {
+	size_t start = pos, match;
+	if (direction < 0 && pos > 0)
+		pos--;
+	for (;;) {
+		char c[3];
+		if (direction > 0)
+			match = text_find_next(txt, pos, "\n}");
+		else
+			match = text_find_prev(txt, pos, "\n}");
+		if (text_bytes_get(txt, match, sizeof c, c) != 3 || c[0] != '\n' || c[1] != '}')
+			break;
+		if (c[2] == '\r' || c[2] == '\n')
+			return match+1;
+		if (match == pos)
+			match += direction;
+		pos = match;
+	}
+	return start;
+}
+
+size_t text_function_end_next(Text *txt, size_t pos) {
+	return text_function_end_direction(txt, pos, +1);
+}
+
+size_t text_function_end_prev(Text *txt, size_t pos) {
+	return text_function_end_direction(txt, pos, -1);
+}
+
 size_t text_bracket_match(Text *txt, size_t pos) {
 	return text_bracket_match_except(txt, pos, NULL);
 }
diff --git a/text-motions.h b/text-motions.h
index c89c256..ce3c5d5 100644
--- a/text-motions.h
+++ b/text-motions.h
@@ -43,6 +43,9 @@ size_t text_line_char_set(Text*, size_t pos, int count);
 /* move to the next/previous character on the same line */
 size_t text_line_char_next(Text*, size_t pos);
 size_t text_line_char_prev(Text*, size_t pos);
+/* move to the next/previous empty line */
+size_t text_line_empty_next(Text*, size_t pos);
+size_t text_line_empty_prev(Text*, size_t pos);
 /* move to same offset in previous/next line */
 size_t text_line_up(Text*, size_t pos);
 size_t text_line_down(Text*, size_t pos);
@@ -86,6 +89,11 @@ size_t text_sentence_prev(Text*, size_t pos);
  */
 size_t text_paragraph_next(Text*, size_t pos);
 size_t text_paragraph_prev(Text*, size_t pos);
+/* Find next/previous start/end of a C like function definition */
+size_t text_function_start_next(Text*, size_t pos);
+size_t text_function_start_prev(Text*, size_t pos);
+size_t text_function_end_next(Text*, size_t pos);
+size_t text_function_end_prev(Text*, size_t pos);
 /* A section begins after a form-feed in the first column.
 size_t text_section_next(Text*, size_t pos);
 size_t text_section_prev(Text*, size_t pos);
diff --git a/vis.c b/vis.c
index c0c7390..aae95f8 100644
--- a/vis.c
+++ b/vis.c
@@ -124,6 +124,10 @@ enum {
 	MOVE_SENTENCE_NEXT,
 	MOVE_PARAGRAPH_PREV,
 	MOVE_PARAGRAPH_NEXT,
+	MOVE_FUNCTION_START_PREV,
+	MOVE_FUNCTION_START_NEXT,
+	MOVE_FUNCTION_END_PREV,
+	MOVE_FUNCTION_END_NEXT,
 	MOVE_BRACKET_MATCH,
 	MOVE_LEFT_TO,
 	MOVE_RIGHT_TO,
@@ -207,6 +211,10 @@ static Movement moves[] = {
 	[MOVE_SENTENCE_NEXT]       = { .txt = text_sentence_next,       .type = LINEWISE           },
 	[MOVE_PARAGRAPH_PREV]      = { .txt = text_paragraph_prev,      .type = LINEWISE|JUMP      },
 	[MOVE_PARAGRAPH_NEXT]      = { .txt = text_paragraph_next,      .type = LINEWISE|JUMP      },
+	[MOVE_FUNCTION_START_PREV] = { .txt = text_function_start_prev, .type = LINEWISE|JUMP      },
+	[MOVE_FUNCTION_START_NEXT] = { .txt = text_function_start_next, .type = LINEWISE|JUMP      },
+	[MOVE_FUNCTION_END_PREV]   = { .txt = text_function_end_prev,   .type = LINEWISE|JUMP      },
+	[MOVE_FUNCTION_END_NEXT]   = { .txt = text_function_end_next,   .type = LINEWISE|JUMP      },
 	[MOVE_BRACKET_MATCH]       = { .txt = text_bracket_match,       .type = INCLUSIVE|JUMP     },
 	[MOVE_FILE_BEGIN]          = { .txt = text_begin,               .type = LINEWISE|JUMP      },
 	[MOVE_FILE_END]            = { .txt = text_end,                 .type = LINEWISE|JUMP      },