added back the files that were accidentally deleted

src/main/java/lua/Builtin.java

@@ -0,0 +1,105 @@
+/**
+ * 
+ */
+package lua;
+
+import java.io.OutputStream;
+import java.io.PrintStream;
+
+import lua.value.LBoolean;
+import lua.value.LFunction;
+import lua.value.LNil;
+import lua.value.LTable;
+import lua.value.LValue;
+
+final class Builtin extends LFunction {
+
+	static void addBuiltins(LTable table) {
+		for ( int i=0; i<NAMES.length; i++ )
+			table.put( NAMES[i], new Builtin(i) );
+	}
+
+	private static final String[] NAMES = { 
+		"print", 
+		"pairs", 
+		"getmetatable", 
+		"setmetatable", 
+		"type", 
+		"pcall", 
+		"ipairs", 
+		};
+	private static final int PRINT = 0;
+	private static final int PAIRS = 1;
+	private static final int GETMETATABLE = 2;
+	private static final int SETMETATABLE = 3;
+	private static final int TYPE = 4;
+	private static final int PCALL = 5;
+	private static final int IPAIRS = 6;
+	
+	private static PrintStream stdout = System.out;
+	
+	private int id;
+	private Builtin( int id ) {			
+		this.id = id;
+	}
+
+	public String toString() {
+		return "builtin."+NAMES[id];
+	}
+	
+	// perform a lua call
+	public boolean luaStackCall(VM vm) {
+		switch ( id ) {
+		case PRINT: {
+				int n = vm.getArgCount();
+				for ( int i=0; i<n; i++ ) {
+					if ( i > 0 )
+						stdout.print( "\t" );
+					stdout.print( vm.getArg(i).luaAsString() );
+				}
+				stdout.println();
+				vm.setResult();
+			}
+			break;
+		case PAIRS:
+		case IPAIRS:
+			vm.setResult( vm.getArg(0).luaPairs(id==PAIRS) );
+			break;
+		case GETMETATABLE:
+			vm.setResult( vm.getArg(0).luaGetMetatable() );
+			break;
+		case SETMETATABLE:
+			LValue t = vm.getArg(0);
+			t.luaSetMetatable(vm.getArg(1));
+			vm.setResult( t );
+			break;
+		case TYPE:
+			vm.setResult( vm.getArg(0).luaGetType() );
+			break;
+		case PCALL: {
+				int n = vm.getArgCount();
+				int s = vm.lua_pcall( n-1, Lua.LUA_MULTRET );
+				if ( s != 0 ) {
+					LValue v = vm.lua_tolvalue(-1);
+					vm.setResult( LBoolean.FALSE );
+					vm.push( v );
+				} else {
+					vm.setResult( LBoolean.TRUE );
+				}
+			}
+			break;
+		default:
+			luaUnsupportedOperation();
+		}
+		return false;
+	}
+	
+	static void redirectOutput( OutputStream newStdOut ) {
+		stdout = new PrintStream( newStdOut );
+	}
+	
+	static void restoreStandardOutput() {
+		stdout = System.out;
+	}
+
+}

src/main/java/lua/GlobalState.java

@@ -0,0 +1,41 @@
+package lua;
+
+import java.util.Hashtable;
+
+import lua.value.LTable;
+
+/**
+** `global state', shared by all threads of this state
+*/
+public class GlobalState {
+
+//	typedef struct global_State {
+	Hashtable strt; /* hash table for strings */
+	StringBuffer buff; /* temporary buffer for string concatentation */
+//	  lu_mem totalbytes;  /* number of bytes currently allocated */
+//	  lu_mem estimate;  /* an estimate of number of bytes actually in use */
+//	  lua_CFunction panic;  /* to be called in unprotected errors */
+//	  TValue l_registry;
+//	  struct lua_State *mainthread;
+	StackState mainthread;
+//	  UpVal uvhead;  /* head of double-linked list of all open upvalues */
+//	  struct Table *mt[NUM_TAGS];  /* metatables for basic types */
+//	  TString *tmname[TM_N];  /* array with tag-method names */
+//	} global_State;
+//
+	private static LTable _G;
+	
+	static {
+		resetGlobals();
+	}
+	
+	static void resetGlobals() {
+		_G = new LTable();
+		_G .put( "_G", _G );
+		Builtin.addBuiltins( _G  );
+	}
+	
+	public static LTable getGlobalsTable() {
+		return _G;
+	}
+}

src/main/java/lua/Lua.java

@@ -0,0 +1,357 @@
+package lua;
+/**
+ * Constants for lua limits and opcodes
+ * 
+ * @author jim_roseborough
+ *
+ */
+public class Lua {
+
+	// from llimits.h
+	
+	/** maximum stack for a Lua function */
+	public static final int MAXSTACK = 250;
+
+	/** minimum size for the string table (must be power of 2) */
+	public static final int MINSTRTABSIZE = 32;
+
+	/** minimum size for string buffer */
+	public static final int LUA_MINBUFFER = 32;
+
+	/** use return values from previous op */
+	public static final int LUA_MULTRET = -1;
+
+	
+	// from lopcodes.h
+
+	/*===========================================================================
+	  We assume that instructions are unsigned numbers.
+	  All instructions have an opcode in the first 6 bits.
+	  Instructions can have the following fields:
+		`A' : 8 bits
+		`B' : 9 bits
+		`C' : 9 bits
+		`Bx' : 18 bits (`B' and `C' together)
+		`sBx' : signed Bx
+
+	  A signed argument is represented in excess K; that is, the number
+	  value is the unsigned value minus K. K is exactly the maximum value
+	  for that argument (so that -max is represented by 0, and +max is
+	  represented by 2*max), which is half the maximum for the corresponding
+	  unsigned argument.
+	===========================================================================*/
+
+
+	/* basic instruction format */
+	public static final int	iABC = 0;
+	public static final int	iABx = 1;
+	public static final int	iAsBx = 2;
+
+
+	/*
+	** size and position of opcode arguments.
+	*/
+	public static final int SIZE_C		= 9;
+	public static final int SIZE_B		= 9;
+	public static final int SIZE_Bx		= (SIZE_C + SIZE_B);
+	public static final int SIZE_A		= 8;
+
+	public static final int SIZE_OP		= 6;
+
+	public static final int POS_OP		= 0;
+	public static final int POS_A		= (POS_OP + SIZE_OP);
+	public static final int POS_C		= (POS_A + SIZE_A);
+	public static final int POS_B		= (POS_C + SIZE_C);
+	public static final int POS_Bx		= POS_C;
+
+
+	public static final int MAX_OP          = ((1<<SIZE_OP)-1);
+	public static final int MAXARG_A        = ((1<<SIZE_A)-1);
+	public static final int MAXARG_B        = ((1<<SIZE_B)-1);
+	public static final int MAXARG_C        = ((1<<SIZE_C)-1);
+	public static final int MAXARG_Bx       = ((1<<SIZE_Bx)-1);
+	public static final int MAXARG_sBx      = (MAXARG_Bx>>1);     	/* `sBx' is signed */
+
+	public static final int MASK_OP = ((1<<SIZE_OP)-1)<<POS_OP; 
+	public static final int MASK_A  = ((1<<SIZE_A)-1)<<POS_A; 
+	public static final int MASK_B  = ((1<<SIZE_B)-1)<<POS_B; 
+	public static final int MASK_C  = ((1<<SIZE_C)-1)<<POS_C; 
+	public static final int MASK_Bx = ((1<<SIZE_Bx)-1)<<POS_Bx; 
+
+	public static final int MASK_NOT_OP = ~MASK_OP; 
+	public static final int MASK_NOT_A  = ~MASK_A; 
+	public static final int MASK_NOT_B  = ~MASK_B; 
+	public static final int MASK_NOT_C  = ~MASK_C; 
+	public static final int MASK_NOT_Bx = ~MASK_Bx; 
+
+	/*
+	** the following macros help to manipulate instructions
+	*/
+	public static int GET_OPCODE(int i) {
+		return (i >> POS_OP) & MAX_OP;
+	}
+
+	public static int GETARG_A(int i) {
+		return (i >> POS_A) & MAXARG_A;
+	}
+
+	public static int GETARG_B(int i) {
+		return (i >> POS_B) & MAXARG_B;
+	}
+
+	public static int GETARG_C(int i) {
+		return (i >> POS_C) & MAXARG_C;
+	}
+
+	public static int GETARG_Bx(int i) {
+		return (i >> POS_Bx) & MAXARG_Bx;
+	}
+
+	public static int GETARG_sBx(int i) {
+		return ((i >> POS_Bx) & MAXARG_Bx) - MAXARG_sBx;
+	}
+
+
+	/*
+	** Macros to operate RK indices
+	*/
+
+	/** this bit 1 means constant (0 means register) */
+	public static final int BITRK		= (1 << (SIZE_B - 1));
+
+	/** test whether value is a constant */
+	public static boolean ISK(int x) {
+		return 0 != ((x) & BITRK);
+	}
+
+	/** gets the index of the constant */
+	public static int INDEXK(int r) {
+		return ((int)(r) & ~BITRK);
+	}
+
+	public static final int MAXINDEXRK	= (BITRK - 1);
+
+	/** code a constant index as a RK value */
+	public static int RKASK(int x) {
+		return ((x) | BITRK);
+	}
+
+
+	/**
+	** invalid register that fits in 8 bits
+	*/
+	public static final int  NO_REG		= MAXARG_A;
+
+
+	/*
+	** R(x) - register
+	** Kst(x) - constant (in constant table)
+	** RK(x) == if ISK(x) then Kst(INDEXK(x)) else R(x)
+	*/
+
+
+	/*
+	** grep "ORDER OP" if you change these enums
+	*/
+
+	/*----------------------------------------------------------------------
+	name		args	description
+	------------------------------------------------------------------------*/
+	public static final int OP_MOVE = 0;/*	A B	R(A) := R(B)					*/
+	public static final int OP_LOADK = 1;/*	A Bx	R(A) := Kst(Bx)					*/
+	public static final int OP_LOADBOOL = 2;/*	A B C	R(A) := (Bool)B; if (C) pc++			*/
+	public static final int OP_LOADNIL = 3; /*	A B	R(A) := ... := R(B) := nil			*/
+	public static final int OP_GETUPVAL = 4; /*	A B	R(A) := UpValue[B]				*/
+
+	public static final int OP_GETGLOBAL = 5; /*	A Bx	R(A) := Gbl[Kst(Bx)]				*/
+	public static final int OP_GETTABLE = 6; /*	A B C	R(A) := R(B)[RK(C)]				*/
+
+	public static final int OP_SETGLOBAL = 7; /*	A Bx	Gbl[Kst(Bx)] := R(A)				*/
+	public static final int OP_SETUPVAL = 8; /*	A B	UpValue[B] := R(A)				*/
+	public static final int OP_SETTABLE = 9; /*	A B C	R(A)[RK(B)] := RK(C)				*/
+
+	public static final int OP_NEWTABLE = 10; /*	A B C	R(A) := {} (size = B,C)				*/
+
+	public static final int OP_SELF = 11; /*	A B C	R(A+1) := R(B); R(A) := R(B)[RK(C)]		*/
+
+	public static final int OP_ADD = 12; /*	A B C	R(A) := RK(B) + RK(C)				*/
+	public static final int OP_SUB = 13; /*	A B C	R(A) := RK(B) - RK(C)				*/
+	public static final int OP_MUL = 14; /*	A B C	R(A) := RK(B) * RK(C)				*/
+	public static final int OP_DIV = 15; /*	A B C	R(A) := RK(B) / RK(C)				*/
+	public static final int OP_MOD = 16; /*	A B C	R(A) := RK(B) % RK(C)				*/
+	public static final int OP_POW = 17; /*	A B C	R(A) := RK(B) ^ RK(C)				*/
+	public static final int OP_UNM = 18; /*	A B	R(A) := -R(B)					*/
+	public static final int OP_NOT = 19; /*	A B	R(A) := not R(B)				*/
+	public static final int OP_LEN = 20; /*	A B	R(A) := length of R(B)				*/
+
+	public static final int OP_CONCAT = 21; /*	A B C	R(A) := R(B).. ... ..R(C)			*/
+
+	public static final int OP_JMP = 22; /*	sBx	pc+=sBx					*/
+
+	public static final int OP_EQ = 23; /*	A B C	if ((RK(B) == RK(C)) ~= A) then pc++		*/
+	public static final int OP_LT = 24; /*	A B C	if ((RK(B) <  RK(C)) ~= A) then pc++  		*/
+	public static final int OP_LE = 25; /*	A B C	if ((RK(B) <= RK(C)) ~= A) then pc++  		*/
+
+	public static final int OP_TEST = 26; /*	A C	if not (R(A) <=> C) then pc++			*/ 
+	public static final int OP_TESTSET = 27; /*	A B C	if (R(B) <=> C) then R(A) := R(B) else pc++	*/ 
+
+	public static final int OP_CALL = 28; /*	A B C	R(A), ... ,R(A+C-2) := R(A)(R(A+1), ... ,R(A+B-1)) */
+	public static final int OP_TAILCALL = 29; /*	A B C	return R(A)(R(A+1), ... ,R(A+B-1))		*/
+	public static final int OP_RETURN = 30; /*	A B	return R(A), ... ,R(A+B-2)	(see note)	*/
+
+	public static final int OP_FORLOOP = 31; /*	A sBx	R(A)+=R(A+2);
+				if R(A) <?= R(A+1) then { pc+=sBx; R(A+3)=R(A) }*/
+	public static final int OP_FORPREP = 32; /*	A sBx	R(A)-=R(A+2); pc+=sBx				*/
+
+	public static final int OP_TFORLOOP = 33; /*	A C	R(A+3), ... ,R(A+2+C) := R(A)(R(A+1), R(A+2)); 
+	                        if R(A+3) ~= nil then R(A+2)=R(A+3) else pc++	*/ 
+	public static final int OP_SETLIST = 34; /*	A B C	R(A)[(C-1)*FPF+i] := R(A+i), 1 <= i <= B	*/
+
+	public static final int OP_CLOSE = 35; /*	A 	close all variables in the stack up to (>=) R(A)*/
+	public static final int OP_CLOSURE = 36; /*	A Bx	R(A) := closure(KPROTO[Bx], R(A), ... ,R(A+n))	*/
+
+	public static final int OP_VARARG = 37; /*	A B	R(A), R(A+1), ..., R(A+B-1) = vararg		*/
+
+
+	public static final int NUM_OPCODES	= OP_VARARG + 1;
+
+
+
+	/*===========================================================================
+	  Notes:
+	  (*) In OP_CALL, if (B == 0) then B = top. C is the number of returns - 1,
+	      and can be 0: OP_CALL then sets `top' to last_result+1, so
+	      next open instruction (OP_CALL, OP_RETURN, OP_SETLIST) may use `top'.
+
+	  (*) In OP_VARARG, if (B == 0) then use actual number of varargs and
+	      set top (like in OP_CALL with C == 0).
+
+	  (*) In OP_RETURN, if (B == 0) then return up to `top'
+
+	  (*) In OP_SETLIST, if (B == 0) then B = `top';
+	      if (C == 0) then next `instruction' is real C
+
+	  (*) For comparisons, A specifies what condition the test should accept
+	      (true or false).
+
+	  (*) All `skips' (pc++) assume that next instruction is a jump
+	===========================================================================*/
+
+
+	/*
+	** masks for instruction properties. The format is:
+	** bits 0-1: op mode
+	** bits 2-3: C arg mode
+	** bits 4-5: B arg mode
+	** bit 6: instruction set register A
+	** bit 7: operator is a test
+	*/  
+
+	  public static final int OpArgN = 0;  /* argument is not used */
+	  public static final int OpArgU = 1;  /* argument is used */
+	  public static final int OpArgR = 2;  /* argument is a register or a jump offset */
+	  public static final int OpArgK = 3;  /* argument is a constant or register/constant */
+
+	  public static final int[] luaP_opmodes = {
+	  /*   T        A           B             C          mode		   opcode	*/
+		 (0<<7) | (1<<6) | (OpArgR<<4) | (OpArgN<<2) | (iABC),		/* OP_MOVE */
+		 (0<<7) | (1<<6) | (OpArgK<<4) | (OpArgN<<2) | (iABx),		/* OP_LOADK */
+		 (0<<7) | (1<<6) | (OpArgU<<4) | (OpArgU<<2) | (iABC),		/* OP_LOADBOOL */
+		 (0<<7) | (1<<6) | (OpArgR<<4) | (OpArgN<<2) | (iABC),		/* OP_LOADNIL */
+		 (0<<7) | (1<<6) | (OpArgU<<4) | (OpArgN<<2) | (iABC),		/* OP_GETUPVAL */
+		 (0<<7) | (1<<6) | (OpArgK<<4) | (OpArgN<<2) | (iABx),		/* OP_GETGLOBAL */
+		 (0<<7) | (1<<6) | (OpArgR<<4) | (OpArgK<<2) | (iABC),		/* OP_GETTABLE */
+		 (0<<7) | (0<<6) | (OpArgK<<4) | (OpArgN<<2) | (iABx),		/* OP_SETGLOBAL */
+		 (0<<7) | (0<<6) | (OpArgU<<4) | (OpArgN<<2) | (iABC),		/* OP_SETUPVAL */
+		 (0<<7) | (0<<6) | (OpArgK<<4) | (OpArgK<<2) | (iABC),		/* OP_SETTABLE */
+		 (0<<7) | (1<<6) | (OpArgU<<4) | (OpArgU<<2) | (iABC),		/* OP_NEWTABLE */
+		 (0<<7) | (1<<6) | (OpArgR<<4) | (OpArgK<<2) | (iABC),		/* OP_SELF */
+		 (0<<7) | (1<<6) | (OpArgK<<4) | (OpArgK<<2) | (iABC),		/* OP_ADD */
+		 (0<<7) | (1<<6) | (OpArgK<<4) | (OpArgK<<2) | (iABC),		/* OP_SUB */
+		 (0<<7) | (1<<6) | (OpArgK<<4) | (OpArgK<<2) | (iABC),		/* OP_MUL */
+		 (0<<7) | (1<<6) | (OpArgK<<4) | (OpArgK<<2) | (iABC),		/* OP_DIV */
+		 (0<<7) | (1<<6) | (OpArgK<<4) | (OpArgK<<2) | (iABC),		/* OP_MOD */
+		 (0<<7) | (1<<6) | (OpArgK<<4) | (OpArgK<<2) | (iABC),		/* OP_POW */
+		 (0<<7) | (1<<6) | (OpArgR<<4) | (OpArgN<<2) | (iABC),		/* OP_UNM */
+		 (0<<7) | (1<<6) | (OpArgR<<4) | (OpArgN<<2) | (iABC),		/* OP_NOT */
+		 (0<<7) | (1<<6) | (OpArgR<<4) | (OpArgN<<2) | (iABC),		/* OP_LEN */
+		 (0<<7) | (1<<6) | (OpArgR<<4) | (OpArgR<<2) | (iABC),		/* OP_CONCAT */
+		 (0<<7) | (0<<6) | (OpArgR<<4) | (OpArgN<<2) | (iAsBx),		/* OP_JMP */
+		 (1<<7) | (0<<6) | (OpArgK<<4) | (OpArgK<<2) | (iABC),		/* OP_EQ */
+		 (1<<7) | (0<<6) | (OpArgK<<4) | (OpArgK<<2) | (iABC),		/* OP_LT */
+		 (1<<7) | (0<<6) | (OpArgK<<4) | (OpArgK<<2) | (iABC),		/* OP_LE */
+		 (1<<7) | (1<<6) | (OpArgR<<4) | (OpArgU<<2) | (iABC),		/* OP_TEST */
+		 (1<<7) | (1<<6) | (OpArgR<<4) | (OpArgU<<2) | (iABC),		/* OP_TESTSET */
+		 (0<<7) | (1<<6) | (OpArgU<<4) | (OpArgU<<2) | (iABC),		/* OP_CALL */
+		 (0<<7) | (1<<6) | (OpArgU<<4) | (OpArgU<<2) | (iABC),		/* OP_TAILCALL */
+		 (0<<7) | (0<<6) | (OpArgU<<4) | (OpArgN<<2) | (iABC),		/* OP_RETURN */
+		 (0<<7) | (1<<6) | (OpArgR<<4) | (OpArgN<<2) | (iAsBx),		/* OP_FORLOOP */
+		 (0<<7) | (1<<6) | (OpArgR<<4) | (OpArgN<<2) | (iAsBx),		/* OP_FORPREP */
+		 (1<<7) | (0<<6) | (OpArgN<<4) | (OpArgU<<2) | (iABC),		/* OP_TFORLOOP */
+		 (0<<7) | (0<<6) | (OpArgU<<4) | (OpArgU<<2) | (iABC),		/* OP_SETLIST */
+		 (0<<7) | (0<<6) | (OpArgN<<4) | (OpArgN<<2) | (iABC),		/* OP_CLOSE */
+		 (0<<7) | (1<<6) | (OpArgU<<4) | (OpArgN<<2) | (iABx),		/* OP_CLOSURE */
+		 (0<<7) | (1<<6) | (OpArgU<<4) | (OpArgN<<2) | (iABC),		/* OP_VARARG */
+	  };
+
+	public static int getOpMode(int m) {
+		return luaP_opmodes[m] & 3;
+	}
+	public static int getBMode(int m) {
+		return (luaP_opmodes[m] >> 4) & 3;
+	}
+	public static int getCMode(int m) {
+		return (luaP_opmodes[m] >> 2) & 3;
+	}
+	public static boolean testAMode(int m) {
+		return 0 != (luaP_opmodes[m] & (1 << 6));
+	}
+	public static boolean testTMode(int m) {
+		return 0 != (luaP_opmodes[m] & (1 << 7));
+	}
+
+
+	/** opcode names */
+	public static final String[] luaP_opnames = {
+		  "MOVE",
+		  "LOADK",
+		  "LOADBOOL",
+		  "LOADNIL",
+		  "GETUPVAL",
+		  "GETGLOBAL",
+		  "GETTABLE",
+		  "SETGLOBAL",
+		  "SETUPVAL",
+		  "SETTABLE",
+		  "NEWTABLE",
+		  "SELF",
+		  "ADD",
+		  "SUB",
+		  "MUL",
+		  "DIV",
+		  "MOD",
+		  "POW",
+		  "UNM",
+		  "NOT",
+		  "LEN",
+		  "CONCAT",
+		  "JMP",
+		  "EQ",
+		  "LT",
+		  "LE",
+		  "TEST",
+		  "TESTSET",
+		  "CALL",
+		  "TAILCALL",
+		  "RETURN",
+		  "FORLOOP",
+		  "FORPREP",
+		  "TFORLOOP",
+		  "SETLIST",
+		  "CLOSE",
+		  "CLOSURE",
+		  "VARARG",
+		  null,
+	};
+
+}

src/main/java/lua/VM.java

@@ -0,0 +1,197 @@
+package lua;
+
+import java.io.InputStream;
+
+import lua.io.Closure;
+import lua.value.LNil;
+import lua.value.LString;
+import lua.value.LValue;
+
+public interface VM {
+
+	// ================ interfaces for performing calls
+	
+	/** Push an argument or return value onto the stack 
+	 */
+	public void push( LValue value );
+
+	/** Push an int argument or return value onto the stack 
+	 */
+	public void push( int value );
+
+	/** Push a double argument or return value onto the stack 
+	 */
+	public void push( double value );
+
+	/** Push a boolean argument or return value onto the stack 
+	 */
+	public void push( boolean value );
+
+	/** Push a String argument or return value onto the stack 
+	 */
+	public void push( String value );
+
+	/**
+	 * Create a call frame for a call that has been set up on
+	 * the stack. The first value on the stack must be a Closure,
+	 * and subsequent values are arguments to the closure.
+	 */ 
+	public void prepStackCall();
+	
+	/**
+	 * Execute bytecodes until the current call completes
+	 * or the vm yields.
+	 */
+	public void execute();
+
+	/**
+	 * Put the closure on the stack with arguments, 
+	 * then perform the call.   Leave return values 
+	 * on the stack for later querying. 
+	 * 
+	 * @param c
+	 * @param values
+	 */
+	public void doCall(Closure c, LValue[] values);	
+	
+	/**
+	 * Set the number of results that are expected from the function being called.
+	 * (This should be called before prepStackCall)
+	 */
+	public void setExpectedResultCount( int nresults );
+	
+	/**
+	 * Returns the number of results that are expected by the calling function,
+	 * or -1 if the calling function can accept a variable number of results.
+	 */
+	public int getExpectedResultCount();
+	
+	/**
+	 * Adjust the stack to contain the expected number of results by adjusting
+	 * the top.
+	 */
+	public void adjustResults();
+	
+	// ================ interfaces for getting arguments when called
+	
+	/**
+	 * Get the number of argumnets supplied in the call.
+	 */
+	public int getArgCount();
+
+	/**
+	 * Get the index-th argument supplied, or NIL if fewer than index were supplied.
+	 * @param index
+	 * @return
+	 */
+	public LValue getArg(int index);
+
+	/**
+	 * Get the index-th argument as an int value, or 0 if fewer than index arguments were supplied.
+	 * @param index
+	 * @return
+	 */
+	public int getArgAsInt( int index );
+
+	/**
+	 * Get the index-th argument as a double value, or 0 if fewer than index arguments were supplied.
+	 * @param index
+	 * @return
+	 */
+	public double getArgAsDouble( int index );
+
+	/**
+	 * Get the index-th argument as a boolean value, or false if fewer than index arguments were supplied.
+	 * @param index
+	 * @return
+	 */
+	public boolean getArgAsBoolean( int index );
+
+	/**
+	 * Get the index-th argument as a String value, or "" if fewer than index arguments were supplied.
+	 * @param index
+	 * @return
+	 */
+	public String getArgAsString( int index );
+
+	/**
+	 * Get the index-th argument as an LString value, or "" if fewer than index arguments were supplied.
+	 * @param index
+	 * @return
+	 */
+	public LString getArgAsLuaString( int index );
+
+	/** Set top to base in preparation for pushing return values.
+	 * Can be used when returning no values.
+	 * 
+	 * Once this is called, calls to getArg() are undefined.
+	 * 
+	 * @see push() to push additional results once result is reset. 
+	 */
+	public void setResult();
+	
+	/** Convenience utility to set val to stack[base] and top to base + 1 
+	 * in preparation for returning one value 
+	 * 
+	 * Once this is called, calls to getArg() are undefined.
+	 * 
+	 * @param val value to provide as the only result.
+	 */
+	public void setResult(LValue val);
+
+
+	/**
+	 * Set up an error result on the stack.
+	 * @param value the LValue to return as the first return value
+	 * @param message the String error message to supply
+	 */
+	public void setErrorResult(LValue value, String message);
+	
+	// ====================== lua Java API =======================
+	
+	/**
+	 * Raises an error.   The message is pushed onto the stack and used as the error message.  
+	 * It also adds at the beginning of the message the file name and the line number where 
+	 * the error occurred, if this information is available.
+	 * 
+	 * In the java implementation this throws a RuntimeException, possibly filling 
+	 * line number information first.
+	 */
+	public void lua_error(String message);
+
+	/** 
+	 * Run the method on the stack, propagating any error that occurs.
+	 * @param nArgs number of arguments on the stack
+	 * @param nResults number of results on the stack
+	 */
+	public void lua_call(int nArgs, int nResults);
+
+	/** 
+	 * Run the method on the stack in protected mode. 
+	 * @param nArgs number of arguments on the stack
+	 * @param nResults number of results on the stack
+	 * @return 0 if successful, LUA_ERRMEM if no memory, LUA_ERRRUN for any other error
+	 */
+	public int lua_pcall(int nArgs, int nResults);
+
+	
+	/**
+	 * 
+	 * @param is InputStream providing the data to be loaded
+	 * @param chunkname Name of the chunk to be used in debugging
+	 * @return 0 if successful, LUA_ERRMEM if no memory, LUA_ERRSYNTAX for i/o or any other errors
+	 */
+	public int lua_load( InputStream is, String chunkname );
+
+	/**
+	 * Get a value on the stack, relative to the top or bottom
+	 * @param i index from bottom if 0 or greater, index from top if less than 0
+	 * @return
+	 */
+	public LValue lua_tolvalue(int i);
+	
+	/**
+	 * Pop some number of items off the stack.
+	 */
+	public void lua_pop(int n);
+}

src/main/java/lua/value/LNumber.java

@@ -0,0 +1,27 @@
+package lua.value;
+
+import lua.Lua;
+
+abstract
+public class LNumber extends LValue {
+
+	public static final LString TYPE_NAME = new LString("number");
+	
+	/** Compare for equivalence by using lua op comparator */
+	public boolean equals(Object o) {
+		if ( ! ( o instanceof LValue) )
+			return false;
+		LValue v = (LValue) o;
+		return this.luaBinCmpUnknown(Lua.OP_EQ, v );
+	}
+
+	public LString luaGetType() {
+		return TYPE_NAME;
+	}
+
+	/**
+	 * Returns false by default for non-LNumbers, but subclasses of LNumber must
+	 * override.
+	 */
+	public abstract boolean isInteger();
+}

src/main/java/lua/value/LValue.java

@@ -0,0 +1,182 @@
+package lua.value;
+
+import lua.Lua;
+import lua.VM;
+
+abstract
+public class LValue {
+
+	/** Metatable tag for intercepting table gets */
+	public static final LString TM_INDEX    = new LString("__index");
+	
+	/** Metatable tag for intercepting table sets */
+	public static final LString TM_NEWINDEX = new LString("__newindex");
+	
+	protected static LValue luaUnsupportedOperation() {
+		throw new java.lang.RuntimeException( "not supported" );
+	}
+
+	public String id() {
+		return Integer.toHexString(hashCode());
+	}
+	
+	// test if value is true
+	public boolean luaAsBoolean() {
+		return true;
+	}
+	
+	/** Return true if this value can be represented as an "int" */
+	public boolean isInteger() {
+		return false;
+	}
+	
+	// perform a lua call, return true if the call is to a lua function, false
+	// if it ran to completion.
+	public boolean luaStackCall(VM vm) {
+		vm.lua_error("attempt to call "+this);
+		return false;
+	}
+
+	// unsupported except for numbers
+	public LValue luaBinOpUnknown(int opcode, LValue lhs) {
+		return luaUnsupportedOperation();
+	}
+
+	// unsupported except for numbers
+	public LValue luaBinOpInteger(int opcode, int m_value) {
+		return luaUnsupportedOperation();
+	}
+
+	// unsupported except for numbers
+	public LValue luaBinOpDouble(int opcode, double m_value) {
+		return luaUnsupportedOperation();
+	}
+
+	// unsupported except for numbers, strings, and == with various combinations of Nil, Boolean, etc. 
+	public boolean luaBinCmpUnknown(int opcode, LValue lhs) {
+		if ( opcode == Lua.OP_EQ )
+			return lhs == this;
+		luaUnsupportedOperation();
+		return false;
+	}
+	
+	// unsupported except for strings
+	public boolean luaBinCmpString(int opcode, LString rhs) {
+		if ( opcode == Lua.OP_EQ )
+			return false;
+		luaUnsupportedOperation();
+		return false;
+	}
+	
+	// unsupported except for numbers
+	public boolean luaBinCmpInteger(int opcode, int rhs) {
+		if ( opcode == Lua.OP_EQ )
+			return false;
+		luaUnsupportedOperation();
+		return false;
+	}
+	
+	// unsupported except for numbers
+	public boolean luaBinCmpDouble(int opcode, double rhs) {
+		if ( opcode == Lua.OP_EQ )
+			return false;
+		luaUnsupportedOperation();
+		return false;
+	}
+	
+	/** set a value in a table
+	 * For non-tables, goes straight to the meta-table.
+	 * @param vm the calling vm
+	 * @param table the table to operate on
+	 * @param the key to set
+	 * @param the value to set
+	 */
+	public void luaSetTable(VM vm, LValue table, LValue key, LValue val) {
+		LTable mt = luaGetMetatable();
+		if ( mt != null ) {
+			LValue event = mt.get( TM_NEWINDEX );
+			if ( event != null && event != LNil.NIL ) {
+				event.luaSetTable( vm, table, key, val );
+				return;
+			}
+		}
+		vm.push( LNil.NIL );
+	}
+	
+	/** Get a value from a table 
+	 * @param vm the calling vm
+	 * @param table the table from which to get the value 
+	 * @param key the key to look up
+	 */
+	public void luaGetTable(VM vm, LValue table, LValue key) {
+		LTable mt = luaGetMetatable();
+		if ( mt != null ) {
+			LValue event = mt.get( TM_INDEX );
+			if ( event != null && event != LNil.NIL ) {
+				event.luaGetTable( vm, table, key );
+				return;
+			}
+		}
+		vm.push(LNil.NIL);
+	}
+	
+	/** Get the value as a String
+	 */
+	public abstract LString luaAsString();
+	
+	/** Override standard toString with lua String conversion by default */
+	public String toString() {
+		return luaAsString().toJavaString();
+	}
+
+	/** Return value as an integer */
+	public int luaAsInt() {
+		luaUnsupportedOperation();
+		return 0;
+	}
+
+	/** Return value as a double */
+	public double luaAsDouble() {
+		return luaAsInt();
+	}
+
+	/** Arithmetic negative */
+	public LValue luaUnaryMinus() {
+		return luaUnsupportedOperation();
+	}
+
+	/** Built-in opcode LEN, for Strings and Tables */
+	public LValue luaLength() {
+		// TODO: call meta-method TM_LEN here
+		return luaUnsupportedOperation();
+	}
+
+	/** Valid for tables 
+	 * @param isPairs true to iterate over non-integers as well */
+	public LValue luaPairs(boolean isPairs) {
+		return luaUnsupportedOperation();
+	}
+
+	/**
+	 * Valid for all types: get a metatable. Only tables and userdata can have a
+	 * different metatable per instance, though, other types are restricted to
+	 * one metatable per type.
+	 * 
+	 * Since metatables on non-tables can only be set through Java and not Lua,
+	 * this function should be overridden for each value type as necessary.
+	 * 
+	 * @return null if there is no meta-table
+	 */
+	public LTable luaGetMetatable() {
+		return null;
+	}
+
+	/** Valid for tables */
+	public void luaSetMetatable(LValue metatable) {
+		luaUnsupportedOperation();
+	}
+
+	/** Valid for all types: return the type of this value as an LString */
+	public abstract LString luaGetType();
+
+}