started syntax higlighting (still need to add state to each line)

1 files changed, 121 insertions, 0 deletions

diff --git a/syntax.c b/syntax.c
new file mode 100644
index 0000000..50e87d9
--- /dev/null
+++ b/syntax.c
@@ -0,0 +1,121 @@
+typedef struct {
+	bool multi_line_comment:1; // are we in a multi-line comment? (delineated by /* */)
+	bool continued_single_line_comment:1; // if you add a \ to the end of a single-line comment, it is continued to the next line.
+	bool continued_preprocessor:1; // similar to above
+	bool continued_string:1;
+} SyntaxStateC;
+
+typedef union {
+	SyntaxStateC c;
+} SyntaxState;
+
+ENUM_U16 {
+	LANG_C
+} ENUM_U16_END(Language);
+
+ENUM_U8 {
+	SYNTAX_NORMAL,
+	SYNTAX_KEYWORD,
+	SYNTAX_COMMENT,
+	SYNTAX_PREPROCESSOR,
+	SYNTAX_STRING,
+	SYNTAX_CHARACTER,
+	SYNTAX_NUMBER
+} ENUM_U8_END(SyntaxCharType);
+
+// NOTE: returns the color setting, not the color
+ColorSetting syntax_char_type_to_color(SyntaxCharType t) {
+	switch (t) {
+	case SYNTAX_NORMAL: return COLOR_TEXT;
+	case SYNTAX_KEYWORD: return COLOR_KEYWORD;
+	case SYNTAX_COMMENT: return COLOR_COMMENT;
+	case SYNTAX_PREPROCESSOR: return COLOR_PREPROCESSOR;
+	case SYNTAX_STRING: return COLOR_STRING;
+	case SYNTAX_CHARACTER: return COLOR_CHARACTER;
+	case SYNTAX_NUMBER: return COLOR_NUMBER;
+	}
+}
+
+static void syntax_highlight_c(SyntaxStateC *state, char32_t *line, u32 line_len, SyntaxCharType *char_types) {
+	(void)state;
+	bool in_preprocessor = state->continued_preprocessor;
+	bool in_string = state->continued_string;
+	bool in_single_line_comment = state->continued_single_line_comment; // this kind of comment :)
+	bool in_multi_line_comment = state->multi_line_comment;
+	int backslashes = 0;
+	for (u32 i = 0; i < line_len; ++i) {
+		SyntaxCharType type = SYNTAX_NORMAL;
+		// necessary for the final " of a string to be highlighted
+		bool in_string_now = in_string;
+		bool in_multi_line_comment_now = in_multi_line_comment;
+
+		// are there 1/2 characters left in the line?
+		bool has_1_char = i + 1 < line_len;
+
+		switch (line[i]) {
+		case '#':
+			if (!in_single_line_comment && !in_multi_line_comment)
+				in_preprocessor = true;
+			break;
+		case '\\':
+			++backslashes;
+			break;
+		case '/':
+			if (!in_multi_line_comment && !in_single_line_comment && !in_string && has_1_char) {
+				if (line[i + 1] == '/')
+					in_single_line_comment = true; // //
+				else if (line[i + 1] == '*')
+					in_multi_line_comment = in_multi_line_comment_now = true; // /*
+			} else if (in_multi_line_comment) {
+				if (i && line[i - 1] == '*') {
+					// */
+					in_multi_line_comment = false;
+				}
+			}
+			break;
+		case '"':
+			if (in_string && backslashes % 2 == 0)
+				in_string = false;
+			else if (!in_multi_line_comment && !in_single_line_comment)
+				in_string = in_string_now = true;
+			break;
+		case '<': // preprocessor string, e.g. <stdio.h>
+			if (in_preprocessor)
+				in_string = in_string_now = true;
+			break;
+		case '>':
+			if (in_preprocessor && in_string)
+				in_string = false;
+			break;
+		}
+		if (line[i] != '\\') backslashes = 0;
+
+		if (in_single_line_comment || in_multi_line_comment_now)
+			type = SYNTAX_COMMENT;
+		else if (in_string_now)
+			type = SYNTAX_STRING;
+		else if (in_preprocessor)
+			type = SYNTAX_PREPROCESSOR;
+
+		if (char_types) {
+			char_types[i] = type;
+		}
+	}
+	state->continued_single_line_comment = backslashes && in_single_line_comment;
+	state->continued_preprocessor = backslashes && in_preprocessor;
+	state->continued_string = backslashes && in_string;
+
+	state->multi_line_comment = in_multi_line_comment;
+}
+
+// This is the main syntax highlighting function. It will determine which colors to use for each character.
+// Rather than returning colors, it returns a character type (e.g. comment) which can be converted to a color.
+// To highlight multiple lines, start out with a zeroed SyntaxState, and pass a pointer to it each time.
+// You can set char_types to NULL if you just want to advance the state, and don't care about the character types.
+void syntax_highlight(SyntaxState *state, Language lang, char32_t *line, u32 line_len, SyntaxCharType *char_types) {
+	switch (lang) {
+	case LANG_C:
+		syntax_highlight_c(&state->c, line, line_len, char_types);
+		break;
+	}
+}