Fixes for string.rep, string.byte, string.lower, and string.upper. Also

factor out negative index handling to separate function, posrelat (to
match C Lua). When converting numbers to strings, see if the double value
can be represented exactly as a long, and if so format the string as
an integer. With these changes the standard test case "strings.lua" runs
to line 104 (over half way through!), where it uses string.format.

src/addon/java/lua/addon/luacompat/LuaCompat.java

@@ -127,7 +127,7 @@ public class LuaCompat extends LFunction {
 	private static final int LEN     = STRING_BASE + 7;
 	private static final int LOWER   = STRING_BASE + 8;
 	private static final int MATCH   = STRING_BASE + 9;
-	private static final int REP     = STRING_BASE + 20;
+	private static final int REP     = STRING_BASE + 10;
 	private static final int REVERSE = STRING_BASE + 11;
 	private static final int SUB     = STRING_BASE + 12;
 	private static final int UPPER   = STRING_BASE + 13;

src/addon/java/lua/addon/luacompat/StrLib.java

@@ -19,14 +19,20 @@ public class StrLib {
 	 */
 	static void byte_( VM vm ) {
 		LString ls = vm.getArgAsLuaString(0);
-		int i = vm.getArgAsInt(1);
-		int j = vm.getArgAsInt(2);
-		int n = ls.length();
-		i = Math.max(1, i);
-		j = Math.min(n, (j==0? i: j));
+		int l = ls.length();
+		final int nargs = vm.getArgCount();
+		int i = posrelat( ( nargs > 1 ) ? vm.getArgAsInt(1) : 1, l );
+		int j = posrelat( ( nargs > 2 ) ? vm.getArgAsInt(2) : i, l );
 		vm.setResult();
-		for ( int k=i; k<=j; k++ ) 
-			vm.push( new LInteger( ls.luaByte(k-1) ) );
+		if ( i <= 0 )
+			i = 1;
+		if ( j > l )
+			j = l;
+		if ( i > j )
+			return;
+		int n = j - i + 1;
+		for ( int k=0; k < n; k++ )
+			vm.push( new LInteger( ls.luaByte(k+i-1) ) );
 	}
 
 	/** 
@@ -200,7 +206,7 @@ public class StrLib {
 	 * The definition of what an uppercase letter is depends on the current locale.
 	 */
 	static void lower( VM vm ) {		
-		vm.setResult( new LString( vm.getArgAsString(1).toLowerCase() ) );
+		vm.setResult( new LString( vm.getArgAsString(0).toLowerCase() ) );
 	}
 
 	/**
@@ -243,10 +249,10 @@ public class StrLib {
 	 * Returns a string that is the string s reversed. 
 	 */
 	static void reverse( VM vm ) {		
-		LString s = vm.getArgAsLuaString(1);
+		LString s = vm.getArgAsLuaString(0);
 		int n = s.length();
 		byte[] b = new byte[n];
-		for ( int i=0, j=n; i<n; i++, j-- ) 
+		for ( int i=0, j=n-1; i<n; i++, j-- )
 			b[j] = (byte) s.luaByte(i);
 		vm.setResult( new LString(b) );
 	}
@@ -263,27 +269,24 @@ public class StrLib {
 	 * returns a suffix of s with length i.
 	 */
 	static void sub( VM vm ) {
+		final int nargs = vm.getArgCount();
 		final LString s = vm.getArgAsLuaString( 0 );
 		final int len = s.length();
 		
-		int i = vm.getArgAsInt( 1 );
-		if ( i < 0 ) {
-			// start at -i characters from the end
-			i = Math.max( len + i, 0 );
-		} else if ( i > 0 ) {
-			// start at character i - 1
-			i = i - 1;
-		}
+		int i = posrelat( nargs > 1 ? vm.getArgAsInt( 1 ) : 1, len );
+		int j = posrelat( nargs > 2 ? vm.getArgAsInt( 2 ) : -1, len );
 		
-		int j = ( vm.getArgCount() > 2 ) ? vm.getArgAsInt( 2 ): -1;
-		if ( j < 0 ) {
-			j = Math.max( i, len + j + 1 );
-		} else {
-			j = Math.min( Math.max( i, j ), len );
-		}
+		if ( i < 1 )
+			i = 1;
+		if ( j > len )
+			j = len;
 		
-		LString result = s.substring( i, j );
+		if ( i <= j ) {
+			LString result = s.substring( i - 1 , j );
 			vm.setResult( result );
+		} else {
+			vm.setResult( new LString( "" ) );
+		}
 	}
 	
 	/** 
@@ -294,7 +297,7 @@ public class StrLib {
 	 * The definition of what a lowercase letter is depends on the current locale.	
 	 */
 	static void upper( VM vm ) {
-		vm.setResult( new LString( vm.getArgAsString(1).toUpperCase() ) );
+		vm.setResult( new LString( vm.getArgAsString(0).toUpperCase() ) );
 	}
 	
 	/**
@@ -351,6 +354,10 @@ public class StrLib {
 		vm.setResult( LNil.NIL );
 	}
 	
+	private static int posrelat( int pos, int len ) {
+		return ( pos >= 0 ) ? pos : len + pos + 1;
+	}
+	
 	// Pattern matching implementation
 	
 	private static final int L_ESC = '%';

src/main/java/lua/value/LDouble.java

@@ -15,8 +15,14 @@ public class LDouble extends LNumber {
 	}
 
 	public LString luaAsString() {
+		long l = (long) m_value;
+		if ( m_value == (double) l ) {
+			// TODO: is this a good idea?
+			return new LString( Long.toString( l ) );
+		} else {
 			return LString.valueOf( m_value );
 		}
+	}
 	
 	public boolean isInteger() {
 		// Cast to int and then back to double and see if the value

src/test/res/strlib.lua

@@ -13,3 +13,9 @@ print( string.match( "abbaaababaabaaabaa", "b(a*)()b" ) )
 print( string.match( "abbaaababaabaaabaa", "b(a*)()b", 3 ) )
 print( string.match( "abbaaababaabaaabaa", "b(a*)()b", 8 ) )
 print( string.match( "abbaaababaabaaabaa", "b(a*)()b", 12 ) )
+
+print( string.byte("hi", -3) )
+
+print( tostring(1234567890123) )
+print( tostring(1234567890124) )
+print( tostring(1234567890125) )