diff -r 31a82b0d0a87 -r ad44e849c60c src/luan/modules/String.luan
--- a/src/luan/modules/String.luan	Mon Jul 18 23:49:47 2022 -0600
+++ b/src/luan/modules/String.luan	Sat Jul 23 21:53:04 2022 -0600
@@ -14,6 +14,7 @@
 String.lower = StringLuan.lower
 String.match = StringLuan.match
 String.matches = StringLuan.matches
+String.regex_compile = Pattern.compile
 String.regex_quote = Pattern.quote
 String.rep = StringLuan.rep
 String.reverse = StringLuan.reverse

diff -r 31a82b0d0a87 -r ad44e849c60c src/luan/modules/StringLuan.java
--- a/src/luan/modules/StringLuan.java	Mon Jul 18 23:49:47 2022 -0600
+++ b/src/luan/modules/StringLuan.java	Sat Jul 23 21:53:04 2022 -0600
@@ -92,13 +92,14 @@
 		return s.substring(start,end);
 	}
 
-	public static Object[] find(String s,String pattern,Integer init,Boolean plain) {
+	public static Object[] find(String s,Object pattern,Integer init,Boolean plain) throws LuanException {
 		int start = start(s,init,0);
 		if( Boolean.TRUE.equals(plain) ) {
-			int i = s.indexOf(pattern,start);
-			return i == -1 ? null : new Integer[]{i+1,i+pattern.length()};
+			String ptn = (String)pattern;
+			int i = s.indexOf(ptn,start);
+			return i == -1 ? null : new Integer[]{i+1,i+ptn.length()};
 		}
-		Matcher m = Pattern.compile(pattern).matcher(s);
+		Matcher m = pattern(pattern).matcher(s);
 		if( !m.find(start) )
 			return null;
 		int n = m.groupCount();
@@ -111,9 +112,9 @@
 		return rtn;
 	}
 
-	public static String[] match(String s,String pattern,Integer init) {
+	public static String[] match(String s,Object pattern,Integer init) throws LuanException {
 		int start = start(s,init,0);
-		Matcher m = Pattern.compile(pattern).matcher(s);
+		Matcher m = pattern(pattern).matcher(s);
 		if( !m.find(start) )
 			return null;
 		int n = m.groupCount();
@@ -126,10 +127,9 @@
 		return rtn;
 	}
 
-	public static LuanFunction gmatch(String s,String pattern) throws LuanException {
+	public static LuanFunction gmatch(String s,Object pattern) throws LuanException {
 		Utils.checkNotNull(s);
-		Utils.checkNotNull(pattern,2);
-		final Matcher m = Pattern.compile(pattern).matcher(s);
+		final Matcher m = pattern(pattern).matcher(s);
 		return new LuanFunction() {
 			@Override public Object call(Luan luan,Object[] args) {
 				if( !m.find() )
@@ -146,10 +146,10 @@
 		};
 	}
 
-	public static Object[] gsub(Luan luan,String s,String pattern,Object repl,Integer n) throws LuanException {
+	public static Object[] gsub(Luan luan,String s,Object pattern,Object repl,Integer n) throws LuanException {
 		Utils.checkNotNull(s);
 		int max = n==null ? Integer.MAX_VALUE : n;
-		final Matcher m = Pattern.compile(pattern).matcher(s);
+		final Matcher m = pattern(pattern).matcher(s);
 		if( repl instanceof String ) {
 			String replacement = (String)repl;
 			int i = 0;
@@ -226,9 +226,19 @@
 		return null;
 	}
 
-	public static boolean matches(String s,String pattern) throws LuanException {
+	private static Pattern pattern(Object pattern) throws LuanException {
+		if( pattern instanceof Pattern ) {
+			return (Pattern)pattern;
+		} else if( pattern instanceof String ) {
+			return Pattern.compile((String)pattern);
+		} else {
+			throw new LuanException( "bad argument #2 (string or compiled pattern expected)" );
+		}
+	}
+
+	public static boolean matches(String s,Object pattern) throws LuanException {
 		Utils.checkNotNull(s);
-		return Pattern.compile(pattern).matcher(s).find();
+		return pattern(pattern).matcher(s).find();
 	}
 
 	public static String[] split(String s,String pattern,Integer limit) throws LuanException {