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Special "constructor methods" -> "new" instruction.

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This simplifies the call instruction a bit (and is overall
less code).
This commit is contained in:
Bob Nystrom
2013-12-13 11:32:47 -08:00
parent d54bca3067
commit 165cf29db0
5 changed files with 45 additions and 74 deletions
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src/wren_compiler.c
+21 -7
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@@ -1568,7 +1568,8 @@ void expression(Compiler* compiler)
}
// Compiles a method definition inside a class body.
void method(Compiler* compiler, Code instruction, SignatureFn signature)
void method(Compiler* compiler, Code instruction, int isConstructor,
SignatureFn signature)
{
Compiler methodCompiler;
int constant = initCompiler(&methodCompiler, compiler->parser, compiler, 1);
@@ -1583,11 +1584,16 @@ void method(Compiler* compiler, Code instruction, SignatureFn signature)
int symbol = ensureSymbol(&compiler->parser->vm->methods, name, length);
consume(compiler, TOKEN_LEFT_BRACE, "Expect '{' to begin method body.");
// If this is a constructor, the first thing is does is create the new
// instance.
if (isConstructor) emit(&methodCompiler, CODE_NEW);
finishBlock(&methodCompiler);
// TODO(bob): Single-expression methods that implicitly return the result.
// If it's a constructor, return "this".
if (instruction == CODE_METHOD_CTOR)
if (isConstructor)
{
// The receiver is always stored in the first local slot.
emit(&methodCompiler, CODE_LOAD_LOCAL);
@@ -1640,7 +1646,10 @@ static void defaultConstructor(Compiler* compiler)
Compiler ctorCompiler;
int constant = initCompiler(&ctorCompiler, compiler->parser, compiler, 1);
// Just return the receiver which is in the first local slot.
// Create the instance of the class.
emit(&ctorCompiler, CODE_NEW);
// Then return the receiver which is in the first local slot.
emit(&ctorCompiler, CODE_LOAD_LOCAL);
emit(&ctorCompiler, 0);
emit(&ctorCompiler, CODE_RETURN);
@@ -1648,7 +1657,7 @@ static void defaultConstructor(Compiler* compiler)
endCompiler(&ctorCompiler, constant);
// Define the constructor method.
emit(compiler, CODE_METHOD_CTOR);
emit(compiler, CODE_METHOD_STATIC);
emit(compiler, ensureSymbol(&compiler->parser->vm->methods, "new", 3));
}
@@ -1695,6 +1704,8 @@ void statement(Compiler* compiler)
while (!match(compiler, TOKEN_RIGHT_BRACE))
{
Code instruction = CODE_METHOD_INSTANCE;
int isConstructor = 0;
if (match(compiler, TOKEN_STATIC))
{
instruction = CODE_METHOD_STATIC;
@@ -1705,8 +1716,11 @@ void statement(Compiler* compiler)
else if (match(compiler, TOKEN_THIS))
{
// If the method name is prefixed with "this", it's a constructor.
instruction = CODE_METHOD_CTOR;
isConstructor = 1;
hasConstructor = 1;
// Constructors are defined on the class.
instruction = CODE_METHOD_STATIC;
}
SignatureFn signature = rules[compiler->parser->current.type].method;
@@ -1718,7 +1732,7 @@ void statement(Compiler* compiler)
break;
}
method(compiler, instruction, signature);
method(compiler, instruction, isConstructor, signature);
consume(compiler, TOKEN_LINE,
"Expect newline after definition in class.");
}
@@ -1894,6 +1908,7 @@ void wrenBindMethod(ObjClass* classObj, ObjFn* fn)
case CODE_IS:
case CODE_CLOSE_UPVALUE:
case CODE_RETURN:
case CODE_NEW:
break;
// Instructions with one argument:
@@ -1952,7 +1967,6 @@ void wrenBindMethod(ObjClass* classObj, ObjFn* fn)
// Instructions with two arguments:
case CODE_METHOD_INSTANCE:
case CODE_METHOD_STATIC:
case CODE_METHOD_CTOR:
ip += 2;
break;