internal IExpression analyze(Object expr, Env env, Loc enclosingLoc)
{
Symbol symbol = expr as Symbol;
if (symbol != null)
{
if (symbol.isDynamic)
{
return(new DynamicVar(symbol));
}
Object var = env.lookup(symbol);
if (var is LocalVariable)
{
return(new LocalVar((LocalVariable)var));
}
else
{
return(new GlobalVar((Symbol)var));
}
}
if (!(expr is Cons)) //must be literal
{
return(new QuoteExpr(expr));
}
Cons exprs = (Cons)expr;
Loc loc = (Loc)reader.locTable[expr];
if (loc != null)
{
reader.locTable.Remove(expr);
}
else
{
loc = enclosingLoc;
}
Object f = exprs.first;
Cons args = exprs.rest;
//see if it's a macro
Symbol s = f as Symbol;
if (s != null && s.isDefined() && s.getGlobalValue() is Macro)
{
Macro m = (Macro)s.getGlobalValue();
Object[] argarray = Cons.ToVector(args);
Object mexprs = null;
try
{
mexprs = m.Invoke(argarray);
}
catch (Exception ex)
{
BacktraceFrame frame = new BacktraceFrame(loc, s, args);
throw BacktraceException.push(ex, frame, this);
}
try
{
return(analyze(mexprs, env, loc));
}
catch (Exception ex)
{
BacktraceFrame frame = new BacktraceFrame(loc, "when expanding ", exprs);
throw BacktraceException.push(ex, frame, this);
}
}
Int32 numargs = Cons.Length(args);
if (f == DLET)
{
return(new DynamicLet(args, env, this, loc));
}
else if (f == FN)
{
return(new Closure(args, env, this, loc));
}
else if (f == MACRO)
{
return(new Macro(args, env, this, loc));
}
else if (f == WHILE)
{
return(new WhileExpression(args, env, this, loc));
}
else if (f == BLOCK)
{
if (numargs == 0)
{
return(new QuoteExpr(null));
}
//remove block from block of one
else if (numargs == 1)
{
return(analyze(args.first, env, loc));
}
else
{
return(new BlockExpression(args, env, this, loc));
}
}
else if (f == OR)
{
if (numargs == 0)
{
return(new QuoteExpr(null));
}
else
{
return(new OrExpression(args, env, this, loc));
}
}
else if (f == IF)
{
return(new IfExpression(args, env, this, loc));
}
else if (f == QUOTE)
{
return(new QuoteExpr(args.first));
}
else if (f == SET)
{
return(new SetExpression(args, env, this, loc));
}
else //presume funcall
{
return(new ApplyExpression(exprs, env, this, loc));
}
}
