public LinkedList <Value> BodyExpression; // (lambda (...) <...>)
public AstLambda(Syntax syntax, Syntax keyword, Environment environment, LinkedList <Value> expression) : base(syntax)
{
ArgList = environment.ToAstArray();
BodyExpression = expression;
if (keyword.GetDatum() == Symbol.LAMBDA)
{
Keyword = keyword;
}
else
{
Keyword = new Syntax(Symbol.LAMBDA, keyword.Location);
}
}
public static Value GetDatum(Syntax syn)
{
return(syn.GetDatum());
}
// aka: x
public static AST ExpandIdentifier(Syntax syntax, Environment env)
{
if (!syntax.IsIdentifier)
{
throw SchemeError.SyntaxError("ast-builder-expand-identifier", "expected identifier", syntax);
}
var varname = syntax.GetDatum().AsSymbol();
// Check and expand some of literals
if (varname == Symbol.NULL)
{
return(new AstLiteral(syntax));
}
// Find the variable in ast environment
int envIdx = 0;
var binding = env.LookupAstRecursively(varname, ref envIdx);
if (binding == null)
{
// If variable is not found designate it as global variable
var localIdx = env.Define(varname, new GlobalBinding(syntax));
return(new AstReference(syntax, AstReferenceType.Global, localIdx));
}
else
{
if (envIdx == 0)
{
// local variable reference
return(new AstReference(syntax, AstReferenceType.Local, binding.VarIdx, 0, 0));
}
else
{
// up-value reference
if (binding is GlobalBinding || !binding.environment.IsLexical)
{
// global variable
var localIdx = env.Define(varname, new GlobalBinding(syntax));
return(new AstReference(syntax, AstReferenceType.Global, localIdx));
}
else if (binding is LocalBinding || binding is ArgumentBinding)
{
// up value to local variable
var localIdx = env.Define(varname, new UpBinding(syntax, envIdx, binding.VarIdx));
return(new AstReference(syntax, AstReferenceType.UpValue, localIdx, envIdx, binding.VarIdx));
}
else if (binding is UpBinding)
{
// upValue to other upValue
var upBinding = binding as UpBinding;
var nEnvIdx = upBinding.UpEnvIdx + envIdx;
var nVarIdx = upBinding.UpVarIdx;
var localIdx = env.Define(varname, new UpBinding(syntax, nEnvIdx, nVarIdx));
return(new AstReference(syntax, AstReferenceType.UpValue, localIdx, nEnvIdx, nVarIdx));
}
else
{
throw new SystemException();
}
}
}
}