// Declares a variable in the current scope whose name is the given token.
//
// If [token] is `null`, uses the previously consumed token. Returns its symbol.
private int DeclareVariable(Token? token)
{
if (token == null) token = _parser.Previous;
Token t = token.Value;
if (t.Length > MaxVariableName)
{
Error(string.Format("Variable name cannot be longer than {0} characters.", MaxVariableName));
}
// Top-level module scope.
if (_scopeDepth == -1)
{
int symbol = _parser.vm.DefineVariable(_parser.Module, _parser.Source.Substring(t.Start, t.Length), Obj.Null);
switch (symbol)
{
case -1:
Error("Module variable is already defined.");
break;
case -2:
Error("Too many module variables defined.");
break;
}
return symbol;
}
string tokenName = _parser.Source.Substring(t.Start, t.Length);
// See if there is already a variable with this name declared in the current
// scope. (Outer scopes are OK: those get shadowed.)
for (int i = _numLocals - 1; i >= 0; i--)
{
Local local = _locals[i];
// Once we escape this scope and hit an outer one, we can stop.
if (local.Depth < _scopeDepth) break;
if (local.Length == t.Length && tokenName == local.Name)
{
Error(string.Format("Variable '{0}' is already declared in this scope.", local.Name));
return i;
}
}
if (_numLocals > MaxLocals)
{
Error(string.Format("Cannot declare more than {0} variables in one scope.", MaxLocals));
return -1;
}
return DefineLocal(tokenName, t.Length);
}
// Declares a variable in the current scope whose name is the given token.
//
// If [token] is `null`, uses the previously consumed token. Returns its symbol.
private int DeclareVariable(Token? token)
{
if (token == null) token = parser.previous;
Token t = token.Value;
if (t.length > MAX_VARIABLE_NAME)
{
Error(string.Format("Variable name cannot be longer than {0} characters.", MAX_VARIABLE_NAME));
}
// Top-level module scope.
if (scopeDepth == -1)
{
int symbol = parser.vm.DefineVariable(parser.module, parser.source.Substring(t.start, t.length), new Value(ValueType.Null));
switch (symbol)
{
case -1:
Error("Module variable is already defined.");
break;
case -2:
Error("Too many module variables defined.");
break;
}
return symbol;
}
// See if there is already a variable with this name declared in the current
// scope. (Outer scopes are OK: those get shadowed.)
for (int i = numLocals - 1; i >= 0; i--)
{
Local local = locals[i];
// Once we escape this scope and hit an outer one, we can stop.
if (local.depth < scopeDepth) break;
if (local.length == t.length && parser.source.Substring(t.start, t.length) == local.name)
{
Error(string.Format("Variable '{0}' is already declared in this scope.", local.name));
return i;
}
}
if (numLocals >= MAX_LOCALS)
{
Error(string.Format("Cannot declare more than {0} variables in one scope.", MAX_LOCALS));
return -1;
}
return DefineLocal(parser.source.Substring(t.start, t.length), t.length);
}