private static void StaticField(Compiler c, bool allowAssignment)
{
Instruction loadInstruction = Instruction.LoadLocal;
int index = 255;
Compiler classCompiler = c.GetEnclosingClassCompiler();
if (classCompiler == null)
{
c.Error("Cannot use a static field outside of a class definition.");
}
else
{
// Look up the name in the scope chain.
Token token = c._parser.Previous;
// If this is the first time we've seen this static field, implicitly
// define it as a variable in the scope surrounding the class definition.
if (classCompiler.ResolveLocal(c._parser.Source.Substring(token.Start, token.Length), token.Length) == -1)
{
int symbol = classCompiler.DeclareVariable(null);
// Implicitly initialize it to null.
classCompiler.Emit(Instruction.Null);
classCompiler.DefineVariable(symbol);
}
// It definitely exists now, so resolve it properly. This is different from
// the above resolveLocal() call because we may have already closed over it
// as an upvalue.
index = c.ResolveName(c._parser.Source.Substring(token.Start, token.Length), token.Length, out loadInstruction);
}
c.Variable(allowAssignment, index, loadInstruction);
}
// Compiles a variable name or method call with an implicit receiver.
private static void Name(Compiler c, bool allowAssignment)
{
// Look for the name in the scope chain up to the nearest enclosing method.
Token token = c._parser.Previous;
Instruction loadInstruction;
string varName = c._parser.Source.Substring(token.Start, token.Length);
int index = c.ResolveNonmodule(varName, token.Length, out loadInstruction);
if (index != -1)
{
c.Variable(allowAssignment, index, loadInstruction);
return;
}
// TODO: The fact that we return above here if the variable is known and parse
// an optional argument list below if not means that the grammar is not
// context-free. A line of code in a method like "someName(foo)" is a parse
// error if "someName" is a defined variable in the surrounding scope and not
// if it isn't. Fix this. One option is to have "someName(foo)" always
// resolve to a self-call if there is an argument list, but that makes
// getters a little confusing.
// If we're inside a method and the name is lowercase, treat it as a method
// on this.
if (IsLocalName(varName) && c.GetEnclosingClass() != null)
{
c.LoadThis();
c.NamedCall(allowAssignment, Instruction.Call0);
return;
}
// Otherwise, look for a module-level variable with the name.
int module = c._parser.Module.Variables.FindIndex(v => v.Name == varName);
if (module == -1)
{
if (IsLocalName(varName))
{
c.Error("Undefined variable.");
return;
}
// If it's a nonlocal name, implicitly define a module-level variable in
// the hopes that we get a real definition later.
module = c._parser.Vm.DeclareVariable(c._parser.Module, varName);
if (module == -2)
{
c.Error("Too many module variables defined.");
}
}
c.Variable(allowAssignment, module, Instruction.LoadModuleVar);
}
