Added new public functions QrSegment.{isNumeric(),isAlphanumeric()} and privatized the regexes in {Java, TypeScript, Python}, because the regexes are awkward compared to a clean abstraction.

java/src/main/java/io/nayuki/qrcodegen/QrSegment.java

@@ -74,7 +74,7 @@ public final class QrSegment {
 	 */
 	public static QrSegment makeNumeric(String digits) {
 		Objects.requireNonNull(digits);
-		if (!NUMERIC_REGEX.matcher(digits).matches())
+		if (!isNumeric(digits))
 			throw new IllegalArgumentException("String contains non-numeric characters");
 		
 		BitBuffer bb = new BitBuffer();
@@ -98,7 +98,7 @@ public final class QrSegment {
 	 */
 	public static QrSegment makeAlphanumeric(String text) {
 		Objects.requireNonNull(text);
-		if (!ALPHANUMERIC_REGEX.matcher(text).matches())
+		if (!isAlphanumeric(text))
 			throw new IllegalArgumentException("String contains unencodable characters in alphanumeric mode");
 		
 		BitBuffer bb = new BitBuffer();
@@ -127,9 +127,9 @@ public final class QrSegment {
 		// Select the most efficient segment encoding automatically
 		List<QrSegment> result = new ArrayList<>();
 		if (text.equals(""));  // Leave result empty
-		else if (NUMERIC_REGEX.matcher(text).matches())
+		else if (isNumeric(text))
 			result.add(makeNumeric(text));
-		else if (ALPHANUMERIC_REGEX.matcher(text).matches())
+		else if (isAlphanumeric(text))
 			result.add(makeAlphanumeric(text));
 		else
 			result.add(makeBytes(text.getBytes(StandardCharsets.UTF_8)));
@@ -162,6 +162,33 @@ public final class QrSegment {
 	}
 	
 	
+	/**
+	 * Tests whether the specified string can be encoded as a segment in numeric mode.
+	 * A string is encodable iff each character is in the range 0 to 9.
+	 * @param text the string to test for encodability (not {@code null})
+	 * @return {@code true} iff each character is in the range 0 to 9.
+	 * @throws NullPointerException if the string is {@code null}
+	 * @see #makeNumeric(String)
+	 */
+	public static boolean isNumeric(String text) {
+		return NUMERIC_REGEX.matcher(text).matches();
+	}
+	
+	
+	/**
+	 * Tests whether the specified string can be encoded as a segment in alphanumeric mode.
+	 * A string is encodable iff each character is in the following set: 0 to 9, A to Z
+	 * (uppercase only), space, dollar, percent, asterisk, plus, hyphen, period, slash, colon.
+	 * @param text the string to test for encodability (not {@code null})
+	 * @return {@code true} iff each character is in the alphanumeric mode character set
+	 * @throws NullPointerException if the string is {@code null}
+	 * @see #makeAlphanumeric(String)
+	 */
+	public static boolean isAlphanumeric(String text) {
+		return ALPHANUMERIC_REGEX.matcher(text).matches();
+	}
+	
+	
 	
 	/*---- Instance fields ----*/
 	
@@ -231,18 +258,11 @@ public final class QrSegment {
 	
 	/*---- Constants ----*/
 	
-	/** Describes precisely all strings that are encodable in numeric mode. To test whether a
-	 * string {@code s} is encodable: {@code boolean ok = NUMERIC_REGEX.matcher(s).matches();}.
-	 * A string is encodable iff each character is in the range 0 to 9.
-	 * @see #makeNumeric(String) */
-	public static final Pattern NUMERIC_REGEX = Pattern.compile("[0-9]*");
+	// Describes precisely all strings that are encodable in numeric mode.
+	private static final Pattern NUMERIC_REGEX = Pattern.compile("[0-9]*");
 	
-	/** Describes precisely all strings that are encodable in alphanumeric mode. To test whether a
-	 * string {@code s} is encodable: {@code boolean ok = ALPHANUMERIC_REGEX.matcher(s).matches();}.
-	 * A string is encodable iff each character is in the following set: 0 to 9, A to Z
-	 * (uppercase only), space, dollar, percent, asterisk, plus, hyphen, period, slash, colon.
-	 * @see #makeAlphanumeric(String) */
-	public static final Pattern ALPHANUMERIC_REGEX = Pattern.compile("[A-Z0-9 $%*+./:-]*");
+	// Describes precisely all strings that are encodable in alphanumeric mode.
+	private static final Pattern ALPHANUMERIC_REGEX = Pattern.compile("[A-Z0-9 $%*+./:-]*");
 	
 	// The set of all legal characters in alphanumeric mode, where
 	// each character value maps to the index in the string.

python/qrcodegen.py

@@ -689,7 +689,7 @@ class QrSegment:
 	@staticmethod
 	def make_numeric(digits: str) -> QrSegment:
 		"""Returns a segment representing the given string of decimal digits encoded in numeric mode."""
-		if QrSegment.NUMERIC_REGEX.fullmatch(digits) is None:
+		if not QrSegment.is_numeric(digits):
 			raise ValueError("String contains non-numeric characters")
 		bb = _BitBuffer()
 		i: int = 0
@@ -705,7 +705,7 @@ class QrSegment:
 		"""Returns a segment representing the given text string encoded in alphanumeric mode.
 		The characters allowed are: 0 to 9, A to Z (uppercase only), space,
 		dollar, percent, asterisk, plus, hyphen, period, slash, colon."""
-		if QrSegment.ALPHANUMERIC_REGEX.fullmatch(text) is None:
+		if not QrSegment.is_alphanumeric(text):
 			raise ValueError("String contains unencodable characters in alphanumeric mode")
 		bb = _BitBuffer()
 		for i in range(0, len(text) - 1, 2):  # Process groups of 2
@@ -727,9 +727,9 @@ class QrSegment:
 		# Select the most efficient segment encoding automatically
 		if text == "":
 			return []
-		elif QrSegment.NUMERIC_REGEX.fullmatch(text) is not None:
+		elif QrSegment.is_numeric(text):
 			return [QrSegment.make_numeric(text)]
-		elif QrSegment.ALPHANUMERIC_REGEX.fullmatch(text) is not None:
+		elif QrSegment.is_alphanumeric(text):
 			return [QrSegment.make_alphanumeric(text)]
 		else:
 			return [QrSegment.make_bytes(text.encode("UTF-8"))]
@@ -755,6 +755,21 @@ class QrSegment:
 		return QrSegment(QrSegment.Mode.ECI, 0, bb)
 	
 	
+	# Tests whether the given string can be encoded as a segment in numeric mode.
+	# A string is encodable iff each character is in the range 0 to 9.
+	@staticmethod
+	def is_numeric(text: str) -> bool:
+		return QrSegment._NUMERIC_REGEX.fullmatch(text) is not None
+	
+	
+	# Tests whether the given string can be encoded as a segment in alphanumeric mode.
+	# A string is encodable iff each character is in the following set: 0 to 9, A to Z
+	# (uppercase only), space, dollar, percent, asterisk, plus, hyphen, period, slash, colon.
+	@staticmethod
+	def is_alphanumeric(text: str) -> bool:
+		return QrSegment._ALPHANUMERIC_REGEX.fullmatch(text) is not None
+	
+	
 	# ---- Private fields ----
 	
 	# The mode indicator of this segment. Accessed through get_mode().
@@ -817,18 +832,13 @@ class QrSegment:
 	
 	# ---- Constants ----
 	
-	# (Public) Describes precisely all strings that are encodable in numeric mode.
-	# To test whether a string s is encodable: ok = NUMERIC_REGEX.fullmatch(s) is not None
-	# A string is encodable iff each character is in the range 0 to 9.
-	NUMERIC_REGEX: re.Pattern = re.compile(r"[0-9]*")
+	# Describes precisely all strings that are encodable in numeric mode.
+	_NUMERIC_REGEX: re.Pattern = re.compile(r"[0-9]*")
 	
-	# (Public) Describes precisely all strings that are encodable in alphanumeric mode.
-	# To test whether a string s is encodable: ok = ALPHANUMERIC_REGEX.fullmatch(s) is not None
-	# A string is encodable iff each character is in the following set: 0 to 9, A to Z
-	# (uppercase only), space, dollar, percent, asterisk, plus, hyphen, period, slash, colon.
-	ALPHANUMERIC_REGEX: re.Pattern = re.compile(r"[A-Z0-9 $%*+./:-]*")
+	# Describes precisely all strings that are encodable in alphanumeric mode.
+	_ALPHANUMERIC_REGEX: re.Pattern = re.compile(r"[A-Z0-9 $%*+./:-]*")
 	
-	# (Private) Dictionary of "0"->0, "A"->10, "$"->37, etc.
+	# Dictionary of "0"->0, "A"->10, "$"->37, etc.
 	_ALPHANUMERIC_ENCODING_TABLE: Dict[str,int] = {ch: i for (i, ch) in enumerate("0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ $%*+-./:")}
 	
 	

typescript-javascript/qrcodegen.ts

@@ -756,7 +756,7 @@ namespace qrcodegen {
 		
 		// Returns a segment representing the given string of decimal digits encoded in numeric mode.
 		public static makeNumeric(digits: string): QrSegment {
-			if (!this.NUMERIC_REGEX.test(digits))
+			if (!QrSegment.isNumeric(digits))
 				throw "String contains non-numeric characters";
 			let bb: Array<bit> = []
 			for (let i = 0; i < digits.length; ) {  // Consume up to 3 digits per iteration
@@ -772,7 +772,7 @@ namespace qrcodegen {
 		// The characters allowed are: 0 to 9, A to Z (uppercase only), space,
 		// dollar, percent, asterisk, plus, hyphen, period, slash, colon.
 		public static makeAlphanumeric(text: string): QrSegment {
-			if (!this.ALPHANUMERIC_REGEX.test(text))
+			if (!QrSegment.isAlphanumeric(text))
 				throw "String contains unencodable characters in alphanumeric mode";
 			let bb: Array<bit> = []
 			let i: int;
@@ -793,9 +793,9 @@ namespace qrcodegen {
 			// Select the most efficient segment encoding automatically
 			if (text == "")
 				return [];
-			else if (this.NUMERIC_REGEX.test(text))
+			else if (QrSegment.isNumeric(text))
 				return [QrSegment.makeNumeric(text)];
-			else if (this.ALPHANUMERIC_REGEX.test(text))
+			else if (QrSegment.isAlphanumeric(text))
 				return [QrSegment.makeAlphanumeric(text)];
 			else
 				return [QrSegment.makeBytes(QrSegment.toUtf8ByteArray(text))];
@@ -822,6 +822,21 @@ namespace qrcodegen {
 		}
 		
 		
+		// Tests whether the given string can be encoded as a segment in numeric mode.
+		// A string is encodable iff each character is in the range 0 to 9.
+		public static isNumeric(text: string): boolean {
+			return QrSegment.NUMERIC_REGEX.test(text);
+		}
+		
+		
+		// Tests whether the given string can be encoded as a segment in alphanumeric mode.
+		// A string is encodable iff each character is in the following set: 0 to 9, A to Z
+		// (uppercase only), space, dollar, percent, asterisk, plus, hyphen, period, slash, colon.
+		public static isAlphanumeric(text: string): boolean {
+			return QrSegment.ALPHANUMERIC_REGEX.test(text);
+		}
+		
+		
 		/*-- Constructor (low level) and fields --*/
 		
 		// Creates a new QR Code segment with the given attributes and data.
@@ -885,16 +900,11 @@ namespace qrcodegen {
 		
 		/*-- Constants --*/
 		
-		// Describes precisely all strings that are encodable in numeric mode. To test
-		// whether a string s is encodable: let ok: boolean = NUMERIC_REGEX.test(s);
-		// A string is encodable iff each character is in the range 0 to 9.
-		public static readonly NUMERIC_REGEX: RegExp = /^[0-9]*$/;
+		// Describes precisely all strings that are encodable in numeric mode.
+		private static readonly NUMERIC_REGEX: RegExp = /^[0-9]*$/;
 		
-		// Describes precisely all strings that are encodable in alphanumeric mode. To test
-		// whether a string s is encodable: let ok: boolean = ALPHANUMERIC_REGEX.test(s);
-		// A string is encodable iff each character is in the following set: 0 to 9, A to Z
-		// (uppercase only), space, dollar, percent, asterisk, plus, hyphen, period, slash, colon.
-		public static readonly ALPHANUMERIC_REGEX: RegExp = /^[A-Z0-9 $%*+.\/:-]*$/;
+		// Describes precisely all strings that are encodable in alphanumeric mode.
+		private static readonly ALPHANUMERIC_REGEX: RegExp = /^[A-Z0-9 $%*+.\/:-]*$/;
 		
 		// The set of all legal characters in alphanumeric mode,
 		// where each character value maps to the index in the string.