[TextServer] Implement ICU/UAX 31 based `is_valid_identifier` function.

core/string/char_utils.h

@@ -33,6 +33,26 @@
 
 #include "core/typedefs.h"
 
+#include "char_range.inc"
+
+static _FORCE_INLINE_ bool is_unicode_identifier_start(char32_t c) {
+	for (int i = 0; xid_start[i].start != 0; i++) {
+		if (c >= xid_start[i].start && c <= xid_start[i].end) {
+			return true;
+		}
+	}
+	return false;
+}
+
+static _FORCE_INLINE_ bool is_unicode_identifier_continue(char32_t c) {
+	for (int i = 0; xid_continue[i].start != 0; i++) {
+		if (c >= xid_continue[i].start && c <= xid_continue[i].end) {
+			return true;
+		}
+	}
+	return false;
+}
+
 static _FORCE_INLINE_ bool is_ascii_upper_case(char32_t c) {
 	return (c >= 'A' && c <= 'Z');
 }

doc/classes/TextServer.xml

@@ -944,6 +944,21 @@
 				Returns [code]true[/code] if locale is right-to-left.
 			</description>
 		</method>
+		<method name="is_valid_identifier" qualifiers="const">
+			<return type="bool" />
+			<argument index="0" name="string" type="String" />
+			<description>
+				Returns [code]true[/code] is [code]string[/code] is a valid identifier.
+				If the text server supports the [constant FEATURE_UNICODE_IDENTIFIERS] feature, a valid identifier must:
+				- Conform to normalization form C.
+				- Begin with a Unicode character of class XID_Start or [code]"_"[/code].
+				- May contain Unicode characters of class XID_Continue in the other positions.
+				- Use UAX #31 recommended scripts only (mixed scripts are allowed).
+				If the [constant FEATURE_UNICODE_IDENTIFIERS] feature is not supported, a valid identifier must:
+				- Begin with a Unicode character of class XID_Start or [code]"_"[/code].
+				- May contain Unicode characters of class XID_Continue in the other positions.
+			</description>
+		</method>
 		<method name="load_support_data">
 			<return type="bool" />
 			<argument index="0" name="filename" type="String" />
@@ -1713,7 +1728,10 @@
 			TextServer supports locale dependent and context sensitive case conversion.
 		</constant>
 		<constant name="FEATURE_USE_SUPPORT_DATA" value="4096" enum="Feature">
-			TextServer require external data file for some features.
+			TextServer require external data file for some features, see [method load_support_data].
+		</constant>
+		<constant name="FEATURE_UNICODE_IDENTIFIERS" value="8192" enum="Feature">
+			TextServer supports UAX #31 identifier validation, see [method is_valid_identifier].
 		</constant>
 		<constant name="CONTOUR_CURVE_TAG_ON" value="1" enum="ContourPointTag">
 			Contour point is on the curve.

doc/classes/TextServerExtension.xml

@@ -941,6 +941,13 @@
 				Returns [code]true[/code] if locale is right-to-left.
 			</description>
 		</method>
+		<method name="is_valid_identifier" qualifiers="virtual const">
+			<return type="bool" />
+			<argument index="0" name="string" type="String" />
+			<description>
+				Returns [code]true[/code] is [code]string[/code] is a valid identifier.
+			</description>
+		</method>
 		<method name="load_support_data" qualifiers="virtual">
 			<return type="bool" />
 			<argument index="0" name="filename" type="String" />

modules/text_server_adv/text_server_adv.cpp

@@ -346,6 +346,7 @@ bool TextServerAdvanced::has_feature(Feature p_feature) const {
 		case FEATURE_FONT_VARIABLE:
 		case FEATURE_CONTEXT_SENSITIVE_CASE_CONVERSION:
 		case FEATURE_USE_SUPPORT_DATA:
+		case FEATURE_UNICODE_IDENTIFIERS:
 			return true;
 		default: {
 		}
@@ -5757,6 +5758,191 @@ PackedInt32Array TextServerAdvanced::string_get_word_breaks(const String &p_stri
 	return ret;
 }
 
+bool TextServerAdvanced::is_valid_identifier(const String &p_string) const {
+	enum UAX31SequenceStatus {
+		SEQ_NOT_STARTED,
+		SEQ_STARTED,
+		SEQ_STARTED_VIR,
+		SEQ_NEAR_END,
+	};
+
+	const char32_t *str = p_string.ptr();
+	int len = p_string.length();
+
+	if (len == 0) {
+		return false; // Empty string.
+	}
+
+	UErrorCode err = U_ZERO_ERROR;
+	Char16String utf16 = p_string.utf16();
+	const UNormalizer2 *norm_c = unorm2_getNFCInstance(&err);
+	if (U_FAILURE(err)) {
+		return false; // Failed to load normalizer.
+	}
+	bool isnurom = unorm2_isNormalized(norm_c, utf16.ptr(), utf16.length(), &err);
+	if (U_FAILURE(err) || !isnurom) {
+		return false; // Do not conform to Normalization Form C.
+	}
+
+	UAX31SequenceStatus A1_sequence_status = SEQ_NOT_STARTED;
+	UScriptCode A1_scr = USCRIPT_INHERITED;
+	UAX31SequenceStatus A2_sequence_status = SEQ_NOT_STARTED;
+	UScriptCode A2_scr = USCRIPT_INHERITED;
+	UAX31SequenceStatus B_sequence_status = SEQ_NOT_STARTED;
+	UScriptCode B_scr = USCRIPT_INHERITED;
+
+	for (int i = 0; i < len; i++) {
+		err = U_ZERO_ERROR;
+		UScriptCode scr = uscript_getScript(str[i], &err);
+		if (U_FAILURE(err)) {
+			return false; // Invalid script.
+		}
+		if (uscript_getUsage(scr) != USCRIPT_USAGE_RECOMMENDED) {
+			return false; // Not a recommended script.
+		}
+		uint8_t cat = u_charType(str[i]);
+		int32_t jt = u_getIntPropertyValue(str[i], UCHAR_JOINING_TYPE);
+
+		// UAX #31 section 2.3 subsections A1, A2 and B, check ZWNJ and ZWJ usage.
+		switch (A1_sequence_status) {
+			case SEQ_NEAR_END: {
+				if ((A1_scr > USCRIPT_INHERITED) && (scr > USCRIPT_INHERITED) && (scr != A1_scr)) {
+					return false; // Mixed script.
+				}
+				if (jt == U_JT_RIGHT_JOINING || jt == U_JT_DUAL_JOINING) {
+					A1_sequence_status = SEQ_NOT_STARTED; // Valid end of sequence, reset.
+				} else if (jt != U_JT_TRANSPARENT) {
+					return false; // Invalid end of sequence.
+				}
+			} break;
+			case SEQ_STARTED: {
+				if ((A1_scr > USCRIPT_INHERITED) && (scr > USCRIPT_INHERITED) && (scr != A1_scr)) {
+					A1_sequence_status = SEQ_NOT_STARTED; // Reset.
+				} else {
+					if (jt != U_JT_TRANSPARENT) {
+						if (str[i] == 0x200C /*ZWNJ*/) {
+							A1_sequence_status = SEQ_NEAR_END;
+							continue;
+						} else {
+							A1_sequence_status = SEQ_NOT_STARTED; // Reset.
+						}
+					}
+				}
+			} break;
+			default:
+				break;
+		}
+		if (A1_sequence_status == SEQ_NOT_STARTED) {
+			if (jt == U_JT_LEFT_JOINING || jt == U_JT_DUAL_JOINING) {
+				A1_sequence_status = SEQ_STARTED;
+				A1_scr = scr;
+			}
+		};
+
+		switch (A2_sequence_status) {
+			case SEQ_NEAR_END: {
+				if ((A2_scr > USCRIPT_INHERITED) && (scr > USCRIPT_INHERITED) && (scr != A2_scr)) {
+					return false; // Mixed script.
+				}
+				if (cat == U_UPPERCASE_LETTER || cat == U_LOWERCASE_LETTER || cat == U_TITLECASE_LETTER || cat == U_MODIFIER_LETTER || cat == U_OTHER_LETTER) {
+					A2_sequence_status = SEQ_NOT_STARTED; // Valid end of sequence, reset.
+				} else if (cat != U_MODIFIER_LETTER || u_getCombiningClass(str[i]) == 0) {
+					return false; // Invalid end of sequence.
+				}
+			} break;
+			case SEQ_STARTED_VIR: {
+				if ((A2_scr > USCRIPT_INHERITED) && (scr > USCRIPT_INHERITED) && (scr != A2_scr)) {
+					A2_sequence_status = SEQ_NOT_STARTED; // Reset.
+				} else {
+					if (str[i] == 0x200C /*ZWNJ*/) {
+						A2_sequence_status = SEQ_NEAR_END;
+						continue;
+					} else if (cat != U_MODIFIER_LETTER || u_getCombiningClass(str[i]) == 0) {
+						A2_sequence_status = SEQ_NOT_STARTED; // Reset.
+					}
+				}
+			} break;
+			case SEQ_STARTED: {
+				if ((A2_scr > USCRIPT_INHERITED) && (scr > USCRIPT_INHERITED) && (scr != A2_scr)) {
+					A2_sequence_status = SEQ_NOT_STARTED; // Reset.
+				} else {
+					if (u_getCombiningClass(str[i]) == 9 /*Virama Combining Class*/) {
+						A2_sequence_status = SEQ_STARTED_VIR;
+					} else if (cat != U_MODIFIER_LETTER) {
+						A2_sequence_status = SEQ_NOT_STARTED; // Reset.
+					}
+				}
+			} break;
+			default:
+				break;
+		}
+		if (A2_sequence_status == SEQ_NOT_STARTED) {
+			if (cat == U_UPPERCASE_LETTER || cat == U_LOWERCASE_LETTER || cat == U_TITLECASE_LETTER || cat == U_MODIFIER_LETTER || cat == U_OTHER_LETTER) {
+				A2_sequence_status = SEQ_STARTED;
+				A2_scr = scr;
+			}
+		}
+
+		switch (B_sequence_status) {
+			case SEQ_NEAR_END: {
+				if ((B_scr > USCRIPT_INHERITED) && (scr > USCRIPT_INHERITED) && (scr != B_scr)) {
+					return false; // Mixed script.
+				}
+				if (u_getIntPropertyValue(str[i], UCHAR_INDIC_SYLLABIC_CATEGORY) != U_INSC_VOWEL_DEPENDENT) {
+					B_sequence_status = SEQ_NOT_STARTED; // Valid end of sequence, reset.
+				} else {
+					return false; // Invalid end of sequence.
+				}
+			} break;
+			case SEQ_STARTED_VIR: {
+				if ((B_scr > USCRIPT_INHERITED) && (scr > USCRIPT_INHERITED) && (scr != B_scr)) {
+					B_sequence_status = SEQ_NOT_STARTED; // Reset.
+				} else {
+					if (str[i] == 0x200D /*ZWJ*/) {
+						B_sequence_status = SEQ_NEAR_END;
+						continue;
+					} else if (cat != U_MODIFIER_LETTER || u_getCombiningClass(str[i]) == 0) {
+						B_sequence_status = SEQ_NOT_STARTED; // Reset.
+					}
+				}
+			} break;
+			case SEQ_STARTED: {
+				if ((B_scr > USCRIPT_INHERITED) && (scr > USCRIPT_INHERITED) && (scr != B_scr)) {
+					B_sequence_status = SEQ_NOT_STARTED; // Reset.
+				} else {
+					if (u_getCombiningClass(str[i]) == 9 /*Virama Combining Class*/) {
+						B_sequence_status = SEQ_STARTED_VIR;
+					} else if (cat != U_MODIFIER_LETTER) {
+						B_sequence_status = SEQ_NOT_STARTED; // Reset.
+					}
+				}
+			} break;
+			default:
+				break;
+		}
+		if (B_sequence_status == SEQ_NOT_STARTED) {
+			if (cat == U_UPPERCASE_LETTER || cat == U_LOWERCASE_LETTER || cat == U_TITLECASE_LETTER || cat == U_MODIFIER_LETTER || cat == U_OTHER_LETTER) {
+				B_sequence_status = SEQ_STARTED;
+				B_scr = scr;
+			}
+		}
+
+		if (u_hasBinaryProperty(str[i], UCHAR_PATTERN_SYNTAX) || u_hasBinaryProperty(str[i], UCHAR_PATTERN_WHITE_SPACE) || u_hasBinaryProperty(str[i], UCHAR_NONCHARACTER_CODE_POINT)) {
+			return false; // Not a XID_Start or XID_Continue character.
+		}
+		if (i == 0) {
+			if (!(cat == U_LOWERCASE_LETTER || cat == U_UPPERCASE_LETTER || cat == U_TITLECASE_LETTER || cat == U_OTHER_LETTER || cat == U_MODIFIER_LETTER || cat == U_LETTER_NUMBER || str[0] == 0x2118 || str[0] == 0x212E || str[0] == 0x309B || str[0] == 0x309C || str[0] == 0x005F)) {
+				return false; // Not a XID_Start character.
+			}
+		} else {
+			if (!(cat == U_LOWERCASE_LETTER || cat == U_UPPERCASE_LETTER || cat == U_TITLECASE_LETTER || cat == U_OTHER_LETTER || cat == U_MODIFIER_LETTER || cat == U_LETTER_NUMBER || cat == U_NON_SPACING_MARK || cat == U_COMBINING_SPACING_MARK || cat == U_DECIMAL_DIGIT_NUMBER || cat == U_CONNECTOR_PUNCTUATION || str[i] == 0x2118 || str[i] == 0x212E || str[i] == 0x309B || str[i] == 0x309C || str[i] == 0x1369 || str[i] == 0x1371 || str[i] == 0x00B7 || str[i] == 0x0387 || str[i] == 0x19DA || str[i] == 0x0E33 || str[i] == 0x0EB3 || str[i] == 0xFF9E || str[i] == 0xFF9F)) {
+				return false; // Not a XID_Continue character.
+			}
+		}
+	}
+	return true;
+}
+
 TextServerAdvanced::TextServerAdvanced() {
 	_insert_num_systems_lang();
 	_insert_feature_sets();

modules/text_server_adv/text_server_adv.h

@@ -702,6 +702,7 @@ public:
 	virtual PackedInt32Array string_get_word_breaks(const String &p_string, const String &p_language = "") const override;
 
 	virtual String strip_diacritics(const String &p_string) const override;
+	virtual bool is_valid_identifier(const String &p_string) const override;
 
 	virtual String string_to_upper(const String &p_string, const String &p_language = "") const override;
 	virtual String string_to_lower(const String &p_string, const String &p_language = "") const override;

servers/text/text_server_extension.cpp

@@ -297,6 +297,7 @@ void TextServerExtension::_bind_methods() {
 	GDVIRTUAL_BIND(percent_sign, "language");
 
 	GDVIRTUAL_BIND(strip_diacritics, "string");
+	GDVIRTUAL_BIND(is_valid_identifier, "string");
 
 	GDVIRTUAL_BIND(string_get_word_breaks, "string", "language");
 
@@ -1498,6 +1499,14 @@ String TextServerExtension::percent_sign(const String &p_language) const {
 	return "%";
 }
 
+bool TextServerExtension::is_valid_identifier(const String &p_string) const {
+	bool ret;
+	if (GDVIRTUAL_CALL(is_valid_identifier, p_string, ret)) {
+		return ret;
+	}
+	return TextServer::is_valid_identifier(p_string);
+}
+
 String TextServerExtension::strip_diacritics(const String &p_string) const {
 	String ret;
 	if (GDVIRTUAL_CALL(strip_diacritics, p_string, ret)) {

servers/text/text_server_extension.h

@@ -496,6 +496,9 @@ public:
 	virtual PackedInt32Array string_get_word_breaks(const String &p_string, const String &p_language = "") const override;
 	GDVIRTUAL2RC(PackedInt32Array, string_get_word_breaks, const String &, const String &);
 
+	virtual bool is_valid_identifier(const String &p_string) const override;
+	GDVIRTUAL1RC(bool, is_valid_identifier, const String &);
+
 	virtual String string_to_upper(const String &p_string, const String &p_language = "") const override;
 	virtual String string_to_lower(const String &p_string, const String &p_language = "") const override;
 	GDVIRTUAL2RC(String, string_to_upper, const String &, const String &);

servers/text_server.cpp

@@ -447,6 +447,7 @@ void TextServer::_bind_methods() {
 	ClassDB::bind_method(D_METHOD("string_get_word_breaks", "string", "language"), &TextServer::string_get_word_breaks, DEFVAL(""));
 
 	ClassDB::bind_method(D_METHOD("strip_diacritics", "string"), &TextServer::strip_diacritics);
+	ClassDB::bind_method(D_METHOD("is_valid_identifier", "string"), &TextServer::is_valid_identifier);
 
 	ClassDB::bind_method(D_METHOD("string_to_upper", "string", "language"), &TextServer::string_to_upper, DEFVAL(""));
 	ClassDB::bind_method(D_METHOD("string_to_lower", "string", "language"), &TextServer::string_to_lower, DEFVAL(""));
@@ -545,6 +546,7 @@ void TextServer::_bind_methods() {
 	BIND_ENUM_CONSTANT(FEATURE_FONT_VARIABLE);
 	BIND_ENUM_CONSTANT(FEATURE_CONTEXT_SENSITIVE_CASE_CONVERSION);
 	BIND_ENUM_CONSTANT(FEATURE_USE_SUPPORT_DATA);
+	BIND_ENUM_CONSTANT(FEATURE_UNICODE_IDENTIFIERS);
 
 	/* FT Contour Point Types */
 	BIND_ENUM_CONSTANT(CONTOUR_CURVE_TAG_ON);
@@ -1730,6 +1732,26 @@ Array TextServer::_shaped_text_get_ellipsis_glyphs_wrapper(const RID &p_shaped)
 	return ret;
 }
 
+bool TextServer::is_valid_identifier(const String &p_string) const {
+	const char32_t *str = p_string.ptr();
+	int len = p_string.length();
+
+	if (len == 0) {
+		return false; // Empty string.
+	}
+
+	if (!is_unicode_identifier_start(str[0])) {
+		return false;
+	}
+
+	for (int i = 1; i < len; i++) {
+		if (!is_unicode_identifier_continue(str[i])) {
+			return false;
+		}
+	}
+	return true;
+}
+
 TextServer::TextServer() {
 	_init_diacritics_map();
 }

servers/text_server.h

@@ -148,6 +148,7 @@ public:
 		FEATURE_FONT_VARIABLE = 1 << 10,
 		FEATURE_CONTEXT_SENSITIVE_CASE_CONVERSION = 1 << 11,
 		FEATURE_USE_SUPPORT_DATA = 1 << 12,
+		FEATURE_UNICODE_IDENTIFIERS = 1 << 13,
 	};
 
 	enum ContourPointTag {
@@ -464,6 +465,7 @@ public:
 	virtual PackedInt32Array string_get_word_breaks(const String &p_string, const String &p_language = "") const = 0;
 
 	virtual String strip_diacritics(const String &p_string) const;
+	virtual bool is_valid_identifier(const String &p_string) const;
 
 	// Other string operations.
 	virtual String string_to_upper(const String &p_string, const String &p_language = "") const = 0;

tests/servers/test_text_server.h

@@ -39,7 +39,7 @@
 
 namespace TestTextServer {
 
-TEST_SUITE("[[TextServer]") {
+TEST_SUITE("[TextServer]") {
 	TEST_CASE("[TextServer] Init, font loading and shaping") {
 		SUBCASE("[TextServer] Loading fonts") {
 			for (int i = 0; i < TextServerManager::get_singleton()->get_interface_count(); i++) {
@@ -492,6 +492,27 @@ TEST_SUITE("[[TextServer]") {
 			}
 		}
 
+		SUBCASE("[TextServer] Unicode identifiers") {
+			for (int i = 0; i < TextServerManager::get_singleton()->get_interface_count(); i++) {
+				Ref<TextServer> ts = TextServerManager::get_singleton()->get_interface(i);
+				TEST_FAIL_COND(ts.is_null(), "Invalid TS interface.");
+
+				static const char32_t *data[19] = { U"-30", U"100", U"10.1", U"10,1", U"1e2", U"1e-2", U"1e2e3", U"0xAB", U"AB", U"Test1", U"1Test", U"Test*1", U"test_testeT", U"test_tes teT", U"عَلَيْكُمْ", U"عَلَيْكُمْTest", U"ӒӖӚӜ", U"_test", U"ÂÃÄÅĀĂĄÇĆĈĊ" };
+				static bool isid[19] = { false, false, false, false, false, false, false, false, true, true, false, false, true, false, true, true, true, true, true };
+				for (int j = 0; j < 19; j++) {
+					String s = String(data[j]);
+					CHECK(ts->is_valid_identifier(s) == isid[j]);
+				}
+
+				if (ts->has_feature(TextServer::FEATURE_UNICODE_IDENTIFIERS)) {
+					// Test UAX 3.2 ZW(N)J usage.
+					CHECK(ts->is_valid_identifier(U"\u0646\u0627\u0645\u0647\u200C\u0627\u06CC"));
+					CHECK(ts->is_valid_identifier(U"\u0D26\u0D43\u0D15\u0D4D\u200C\u0D38\u0D3E\u0D15\u0D4D\u0D37\u0D3F"));
+					CHECK(ts->is_valid_identifier(U"\u0DC1\u0DCA\u200D\u0DBB\u0DD3"));
+				}
+			}
+		}
+
 		SUBCASE("[TextServer] Strip Diacritics") {
 			for (int i = 0; i < TextServerManager::get_singleton()->get_interface_count(); i++) {
 				Ref<TextServer> ts = TextServerManager::get_singleton()->get_interface(i);