Initial implementation of module, package.seeall

src/core/org/luaj/lib/BaseLib.java

@@ -153,7 +153,7 @@ public class BaseLib extends LFunction {
 		}
 		case GETMETATABLE: {
 			checkargexists(vm,2,Lua.LUA_TVALUE);
-			if ( 0 == vm.getmetatable(2) ) {
+			if ( ! vm.getmetatable(2) ) {
 				vm.resettop();
 				vm.pushnil();
 			} else {
@@ -248,14 +248,16 @@ public class BaseLib extends LFunction {
 			vm.pushlvalue(t);
 		}	break;
 		case GETFENV: {
-			if ( vm.gettop() <= 1 ) {
+			if ( vm.isfunction(2) ) {
-				vm.pushlvalue(vm._G);
-			} else {
-				if ( ! vm.isfunction(2) ) {
-					int i = (vm.isnil(2)? 1: vm.tointeger(2));
-					vm.pushlvalue( vm.getStackFrame(i).closure );
-				}
 				vm.getfenv(-1);
+			} else {
+				int i = (vm.isnil(2)? 1: vm.tointeger(2));
+				if ( i <= 0 )
+					vm.pushlvalue(vm._G);
+				else if ( i-1 <= vm.cc )
+					vm.pushlvalue( vm.getStackFrame(i-1).closure.env );
+				else
+					vm.pushnil();
 			}
 			vm.insert(1);
 			vm.settop(1);

src/core/org/luaj/lib/PackageLib.java

@@ -24,12 +24,14 @@ package org.luaj.lib;
 import java.io.InputStream;
 import java.io.PrintStream;
 
+import org.luaj.vm.CallInfo;
 import org.luaj.vm.LBoolean;
 import org.luaj.vm.LFunction;
 import org.luaj.vm.LNil;
 import org.luaj.vm.LString;
 import org.luaj.vm.LTable;
 import org.luaj.vm.LValue;
+import org.luaj.vm.Lua;
 import org.luaj.vm.LuaState;
 
 
@@ -39,6 +41,13 @@ public class PackageLib extends LFunction {
 	public static PrintStream STDOUT = System.out;
 	public static LTable      LOADED = new LTable();
 
+	private static final LString _M = new LString("_M");
+	private static final LString _NAME = new LString("_NAME");	
+	private static final LString _PACKAGE = new LString("_PACKAGE");	
+	private static final LString _DOT = new LString(".");
+	private static final LString _EMPTY = new LString("");
+	private static final LString __INDEX = new LString("__index");
+	
 	private static final String[] NAMES = {
 		"package",
 		"module",
@@ -53,6 +62,7 @@ public class PackageLib extends LFunction {
 	private static final int LOADLIB        = 3;
 	private static final int SEEALL         = 4;
 	
+	
 	public static void install( LTable globals ) {
 		for ( int i=1; i<LOADLIB; i++ )
 			globals.put( NAMES[i], new PackageLib(i) );
@@ -87,9 +97,17 @@ public class PackageLib extends LFunction {
 		case LOADLIB: 
 			loadlib(vm);
 			break;
-		case SEEALL: 
+		case SEEALL: { 
-			seeall(vm);
+			if ( ! vm.istable(2) )
+				vm.error( "table expected, got "+vm.typename(2) );
+			LTable t = vm.totable(2);
+			LTable m = t.luaGetMetatable();
+			if ( m == null )
+				t.luaSetMetatable(m = new LTable());
+			m.put(__INDEX, vm._G);
+			vm.resettop();
 			break;
+		}
 		default:
 			luaUnsupportedOperation();
 		}
@@ -98,9 +116,98 @@ public class PackageLib extends LFunction {
 	
 	
 	// ======================== Module, Package loading =============================
+	/**
+	 * module (name [, ···])
+	 * 
+	 * Creates a module. If there is a table in package.loaded[name], this table
+	 * is the module. Otherwise, if there is a global table t with the given
+	 * name, this table is the module. Otherwise creates a new table t and sets
+	 * it as the value of the global name and the value of package.loaded[name].
+	 * This function also initializes t._NAME with the given name, t._M with the
+	 * module (t itself), and t._PACKAGE with the package name (the full module
+	 * name minus last component; see below). Finally, module sets t as the new
+	 * environment of the current function and the new value of
+	 * package.loaded[name], so that require returns t.
+	 * 
+	 * If name is a compound name (that is, one with components separated by
+	 * dots), module creates (or reuses, if they already exist) tables for each
+	 * component. For instance, if name is a.b.c, then module stores the module
+	 * table in field c of field b of global a.
+	 * 
+	 * This function may receive optional options after the module name, where
+	 * each option is a function to be applied over the module.
+	 */
+	public static void module(LuaState vm) {
+		LString modname = vm.tolstring(2);
+		int n = vm.gettop();
+		LValue value = LOADED.get(modname);
+		LTable module;
+		if ( value.luaGetType() != Lua.LUA_TTABLE ) { /* not found? */
 			
-	public static void module( LuaState vm ) {		
+		    /* try global variable (and create one if it does not exist) */
-		vm.error( "module not implemented" );
+			module = findtable( vm._G, modname );
+			if ( module == null )
+				vm.error( "name conflict for module '"+modname+"'", 2 );
+			LOADED.luaSetTable(vm, LOADED, modname, module);
+		} else {
+			module = (LTable) value;
+		}
+		
+		
+		/* check whether table already has a _NAME field */
+		module.luaGetTable(vm, module, _NAME);
+		if ( vm.isnil(-1) ) {
+			modinit( vm, module, modname );
+		}
+		
+		// set the environment of the current function
+		CallInfo ci = vm.getStackFrame(0);
+		ci.closure.env = module;
+		
+		// apply the functions
+		for ( int i=3; i<=n; i++ ) {
+			vm.pushvalue( i );   /* get option (a function) */
+			vm.pushlvalue( module );  /* module */
+			vm.call( 1, 0 );
+		}
+		
+		// returns no results
+		vm.resettop();
+	}
+
+	/**
+	 * 
+	 * @param table the table at which to start the search
+	 * @param fname the name to look up or create, such as "abc.def.ghi"
+	 * @return the table for that name, possible a new one, or null if a non-table has that name already. 
+	 */
+	private static LTable findtable(LTable table, LString fname) {
+		int b, e=(-1);
+		do {
+			e = fname.indexOf(_DOT, b=e+1 );
+			if ( e < 0 )
+				e = fname.m_length;
+			LString key = fname.substring(b, e);
+			LValue val = table.get(key);
+			if ( val == LNil.NIL ) { /* no such field? */
+				LTable field = new LTable(); /* new table for field */
+				table.put(key, field);
+				table = field;
+			} else if ( val.luaGetType() != Lua.LUA_TTABLE ) {  /* field has a non-table value? */
+				return null;
+			} else {
+				table = (LTable) val;
+			}
+		} while ( e < fname.m_length );
+		return table;
+	}
+
+	private static void modinit(LuaState vm, LTable module, LString modname) {
+		/* module._M = module */
+		module.luaSetTable(vm, module, _M, module);
+		int e = modname.lastIndexOf(_DOT);
+		module.luaSetTable(vm, module, _NAME, modname );
+		module.luaSetTable(vm, module, _PACKAGE, (e<0? _EMPTY: modname.substring(0,e+1)) );
 	}
 
 	/** 
@@ -154,8 +261,4 @@ public class PackageLib extends LFunction {
 	public static void loadlib( LuaState vm ) {
 		vm.error( "loadlib not implemented" );
 	}
-	
-	public static void seeall( LuaState vm ) {
-		vm.error( "seeall not implemented" );
-	}
 }

src/core/org/luaj/vm/LNil.java

@@ -72,4 +72,5 @@ public final class LNil extends LValue {
 	public Short toJavaBoxedShort() {
 		return null;
 	}
+	
 }

src/core/org/luaj/vm/LString.java

@@ -222,6 +222,17 @@ public class LString extends LValue {
 		return -1;
 	}
 	
+	public int lastIndexOf( LString s ) {
+		final int slen = s.length();
+		final int limit = m_offset + m_length - slen;
+		for ( int i = limit; i >= m_offset; --i ) {
+			if ( equals( m_bytes, i, s.m_bytes, s.m_offset, slen ) ) {
+				return i;
+			}
+		}
+		return -1;
+	}
+	
 	public static LString valueOf( double d ) {
 		return new LString( String.valueOf( d ) );
 	}

src/core/org/luaj/vm/LuaState.java

@@ -1355,15 +1355,17 @@ public class LuaState extends Lua {
 	 * <p>
 	 * Pushes onto the stack the metatable of the value at the given acceptable
 	 * index. If the index is not valid, or if the value does not have a
-	 * metatable, the function returns&nbsp;0 and pushes nothing on the stack.
+	 * metatable, the function returns false and pushes nothing on the stack.
+	 * 
+	 * @return true if the metatable was pushed onto the stack, false otherwise
 	 */
-	public int getmetatable(int index) {
+	public boolean getmetatable(int index) {
 		LTable mt = topointer(index).luaGetMetatable();
 		if ( mt != null ) {
 			pushlvalue( mt );
-			return 1;			
+			return true;			
 		}
-		return 0;
+		return false;
 	}
 	
 	/**

src/test/java/org/luaj/vm/LuaJTest.java

@@ -78,6 +78,10 @@ public class LuaJTest extends TestCase {
 		runTest( "metatables" );
 	}
 
+	public void testModule() throws IOException, InterruptedException {
+		runTest( "module" );
+	}
+
 	public void testNext() throws IOException, InterruptedException {
 		runTest( "next" );
 	}

src/test/res/module.lua

@@ -0,0 +1,63 @@
+-- unit tests for module() function
+local ids = {}
+local function id(obj)
+	if not obj or type(obj) == 'number' or type(obj) == 'string' then
+		return obj
+	end
+	local v = ids[obj]
+	if v then
+		return v
+	end
+	table.insert(ids,obj)
+	ids[obj] = type(obj)..'.'..tostring(#ids)
+	return ids[obj]
+end 
+
+-- module tests
+local pr = print
+local pkg = package
+local g = _G
+local md = module
+local rq = require
+local sa = package.seeall
+local gfe = getfenv
+local gmt = getmetatable
+local function envs()
+	return id(gfe(0)), id(gfe(1)), id(gfe(2)), 
+		 id(gmt(gfe(0))), id(gmt(gfe(1))), id(gmt(gfe(2)))
+end
+local function trymodule(name)
+	pr( '_G['..name..']', id(g[name]) )
+	pr( 'pkg.loaded['..name..']', id(pkg.loaded[name]) )
+	pr( 'envs', envs() )
+	md(name)
+	pr( 'envs', envs() )
+	pr( 'status,result', status, result )
+	pr( '_G['..name..']', id(g[name]) )
+	local t = pkg.loaded[name]
+	pr( 't=pkg.loaded['..name..']', id(t) )
+	pr( 't._M, t._NAME, t._PACKAGE', id(t._M), id(t._NAME), id(t._PACKAGE) )
+	pr( 'rq('..name..')', id( rq(name) ) )
+	pr( 'print', id(print) )
+	pr( 'seeall(t)', sa(t) )
+	pr( 'print, _G['..name..']', id(print), id(g[name]) )
+end
+trymodule('abc.def.ghi')
+trymodule('abc.def.ghi')
+trymodule('abc.def')
+trymodule('abc.def.lmn')
+trymodule('abc.def')
+trymodule('abc')
+package.loaded['opq.rst'] = {}
+trymodule('opq.rst')
+trymodule('opq.rst')
+uvw = { xyz="x1y1z1" }
+--print( "uvw", id(uvw) )
+--print( "uvw.xyz", id(uvw.xyz) )
+--print( "uvw.abc", id(uvw.abc) )
+print( pcall( trymodule, 'uvw.xyz' ) )
+print( pcall( trymodule, 'uvw' ) )
+print( pcall( trymodule, 'uvw.abc' ) )
+print( "uvw", id(uvw) )
+print( "uvw.xyz", id(uvw.xyz) )
+print( "uvw.abc", id(uvw.abc) )