Add `-vet-tabs`

src/build_settings.cpp

@@ -282,6 +282,7 @@ enum VetFlags : u64 {
 	VetFlag_UnusedImports   = 1u<<6,
 	VetFlag_Deprecated      = 1u<<7,
 	VetFlag_Cast            = 1u<<8,
+	VetFlag_Tabs            = 1u<<9,
 
 	VetFlag_Unused = VetFlag_UnusedVariables|VetFlag_UnusedImports,
 
@@ -311,6 +312,8 @@ u64 get_vet_flag_from_name(String const &name) {
 		return VetFlag_Deprecated;
 	} else if (name == "cast") {
 		return VetFlag_Cast;
+	} else if (name == "tabs") {
+		return VetFlag_Tabs;
 	}
 	return VetFlag_NONE;
 }

src/main.cpp

@@ -301,6 +301,7 @@ enum BuildFlagKind {
 	BuildFlag_VetStyle,
 	BuildFlag_VetSemicolon,
 	BuildFlag_VetCast,
+	BuildFlag_VetTabs,
 
 	BuildFlag_CustomAttribute,
 	BuildFlag_IgnoreUnknownAttributes,
@@ -502,6 +503,7 @@ gb_internal bool parse_build_flags(Array<String> args) {
 	add_flag(&build_flags, BuildFlag_VetStyle,                str_lit("vet-style"),                 BuildFlagParam_None,    Command__does_check);
 	add_flag(&build_flags, BuildFlag_VetSemicolon,            str_lit("vet-semicolon"),             BuildFlagParam_None,    Command__does_check);
 	add_flag(&build_flags, BuildFlag_VetCast,                 str_lit("vet-cast"),                  BuildFlagParam_None,    Command__does_check);
+	add_flag(&build_flags, BuildFlag_VetTabs,                 str_lit("vet-tabs"),                  BuildFlagParam_None,    Command__does_check);
 
 	add_flag(&build_flags, BuildFlag_CustomAttribute,         str_lit("custom-attribute"),          BuildFlagParam_String,  Command__does_check, true);
 	add_flag(&build_flags, BuildFlag_IgnoreUnknownAttributes, str_lit("ignore-unknown-attributes"), BuildFlagParam_None,    Command__does_check);
@@ -1157,6 +1159,7 @@ gb_internal bool parse_build_flags(Array<String> args) {
 						case BuildFlag_VetStyle:           build_context.vet_flags |= VetFlag_Style;           break;
 						case BuildFlag_VetSemicolon:       build_context.vet_flags |= VetFlag_Semicolon;       break;
 						case BuildFlag_VetCast:            build_context.vet_flags |= VetFlag_Cast;            break;
+						case BuildFlag_VetTabs:            build_context.vet_flags |= VetFlag_Tabs;            break;
 
 						case BuildFlag_CustomAttribute:
 							{
@@ -2256,6 +2259,10 @@ gb_internal void print_show_help(String const arg0, String const &command) {
 		print_usage_line(1, "-vet-cast");
 		print_usage_line(2, "Errs on casting a value to its own type or using `transmute` rather than `cast`.");
 		print_usage_line(0, "");
+
+		print_usage_line(1, "-vet-tabs");
+		print_usage_line(2, "Errs when the use of tabs has not been used for indentation.");
+		print_usage_line(0, "");
 	}
 
 	if (check) {

src/parser.cpp

@@ -5286,12 +5286,53 @@ gb_internal Ast *parse_stmt(AstFile *f) {
 	return ast_bad_stmt(f, token, f->curr_token);
 }
 
+
+
+gb_internal u64 check_vet_flags(AstFile *file) {
+	if (file && file->vet_flags_set) {
+		return file->vet_flags;
+	}
+	return build_context.vet_flags;
+}
+
+
+gb_internal void parse_enforce_tabs(AstFile *f) {
+       	Token prev = f->prev_token;
+	Token curr = f->curr_token;
+	if (prev.pos.line < curr.pos.line) {
+		u8 *start = f->tokenizer.start+prev.pos.offset;
+		u8 *end   = f->tokenizer.start+curr.pos.offset;
+		u8 *it = end;
+		while (it > start) {
+			if (*it == '\n') {
+				it++;
+				break;
+			}
+			it--;
+		}
+
+		isize len = end-it;
+		for (isize i = 0; i < len; i++) {
+			if (it[i] == ' ') {
+				syntax_error(curr, "With '-vet-tabs', tabs must be used for indentation");
+				break;
+			}
+		}
+	}
+}
+
 gb_internal Array<Ast *> parse_stmt_list(AstFile *f) {
 	auto list = array_make<Ast *>(ast_allocator(f));
 
 	while (f->curr_token.kind != Token_case &&
 	       f->curr_token.kind != Token_CloseBrace &&
 	       f->curr_token.kind != Token_EOF) {
+
+		// Checks to see if tabs have been used for indentation
+	       	if (check_vet_flags(f) & VetFlag_Tabs) {
+		       parse_enforce_tabs(f);
+		}
+
 		Ast *stmt = parse_stmt(f);
 		if (stmt && stmt->kind != Ast_EmptyStmt) {
 			array_add(&list, stmt);