public static Object second(params Object[] args)
{
Cons x = (Cons)arg(0, args);
if (x == null)
{
return(null);
}
return(Cons.Second(x));;
}
internal SetExpression(Cons args, Env env, Interpreter interpreter, Loc loc)
{
this.loc = loc;
this.interpreter = interpreter;
Int32 len = Cons.Length(args);
if (len != 2)
{
throw new Exception("Wrong number of args for set");
}
var = (IVar)interpreter.analyze(args.first, env, loc);
val = interpreter.analyze(Cons.Second(args), env, loc);
}
internal IfExpression(Cons args, Env env, Interpreter interpreter, Loc loc)
{
this.loc = loc;
this.interpreter = interpreter;
Int32 len = Cons.Length(args);
if (len < 2 || len > 3)
{
throw new Exception("Wrong number of args for if");
}
test = interpreter.analyze(args.first, env, loc);
brtrue = interpreter.analyze(Cons.Second(args), env, loc);
if (len == 3)
{
brfalse = interpreter.analyze(Cons.Third(args), env, loc);
}
else
{
brfalse = new QuoteExpr(null);
}
}
internal Object findKeyParamValue(Parameter p, Cons args)
{
for (; args != null; args = args.rest)
{
if (args.first == p.key)
{
if (args.rest != null)
{
Object ret = Cons.Second(args);
if (ret == Missing.Value)
{
ret = getDefaultParamValue(p);
}
return(ret);
}
else
{
throw new Exception("Key args must be provided in pairs of [:key value]");
}
}
}
return(getDefaultParamValue(p));
}
//parse out params from spec (which may contain &optional, &key, &rest, initforms etc
internal ArgSpecs analyzeArgSpec(Cons arglist, Env env, Loc loc)
{
//count the params
int nParams = 0;
Cons a = arglist;
while (a != null)
{
Object p = a.first;
if (p != interpreter.AMPOPT && p != interpreter.AMPKEY && p != interpreter.AMPREST)
{
++nParams;
}
a = a.rest;
}
ArgSpecs ret = new ArgSpecs(env);
ret.parameters = new Parameter[nParams];
Parameter.Spec state = Parameter.Spec.REQ;
int param = 0;
a = arglist;
while (a != null)
{
Object p = a.first;
switch (state)
{
case Parameter.Spec.REQ:
if (p == interpreter.AMPOPT)
{
state = Parameter.Spec.OPT;
}
else if (p == interpreter.AMPKEY)
{
state = Parameter.Spec.KEY;
}
else if (p == interpreter.AMPREST)
{
state = Parameter.Spec.REST;
}
else
{
if (p is Symbol)
{
ret.parameters[param++] =
new Parameter((Symbol)p, Parameter.Spec.REQ, null);
++ret.numReq;
}
else if (p is Cons)
{
ret.parameters[param] =
new Parameter((Symbol)((Cons)p).first, Parameter.Spec.REQ, null);
ret.parameters[param].typeSpec = interpreter.eval(Cons.Second((Cons)p), env);
++param;
++ret.numReq;
}
}
break;
case Parameter.Spec.OPT:
if (p == interpreter.AMPOPT)
{
throw new Exception("&optional can appear only once in arg list");
}
else if (p == interpreter.AMPKEY)
{
state = Parameter.Spec.KEY;
}
else if (p == interpreter.AMPREST)
{
state = Parameter.Spec.REST;
}
else
{
if (p is Symbol)
{
ret.parameters[param++] =
new Parameter((Symbol)p, Parameter.Spec.OPT, null);
++ret.numOpt;
}
else if (p is Cons)
{
ret.parameters[param++] =
new Parameter((Symbol)((Cons)p).first, Parameter.Spec.OPT,
interpreter.analyze(Cons.Second((Cons)p), env, loc));
++ret.numOpt;
}
else
{
throw new Exception("&optional parameters must be symbols or (symbol init-form)");
}
}
break;
case Parameter.Spec.KEY:
if (p == interpreter.AMPOPT)
{
throw new Exception("&optional must appear before &key in arg list");
}
else if (p == interpreter.AMPKEY)
{
throw new Exception("&key can appear only once in arg list");
}
else if (p == interpreter.AMPREST)
{
state = Parameter.Spec.REST;
}
else
{
if (p is Symbol)
{
ret.parameters[param] =
new Parameter((Symbol)p, Parameter.Spec.KEY, null);
ret.parameters[param].key = interpreter.intern(":" + ((Symbol)p).name);
++param;
++ret.numKey;
}
else if (p is Cons)
{
ret.parameters[param] =
new Parameter((Symbol)((Cons)p).first, Parameter.Spec.KEY,
interpreter.analyze(Cons.Second((Cons)p), env, loc));
ret.parameters[param].key =
interpreter.intern(":" + ((Symbol)((Cons)p).first).name);
++param;
++ret.numKey;
}
else
{
throw new Exception("&key parameters must be symbols or (symbol init-form)");
}
}
break;
case Parameter.Spec.REST:
if (p == interpreter.AMPOPT)
{
throw new Exception("&optional must appear before &rest in arg list");
}
else if (p == interpreter.AMPKEY)
{
throw new Exception("&key must appear before &rest in arg list");
}
else if (p == interpreter.AMPREST)
{
throw new Exception("&rest can appear only once in arg list");
}
else
{
if (!(p is Symbol))
{
throw new Exception("&rest parameter must be a symbol");
}
else
{
if (ret.numRest > 0) //already got a rest param
{
throw new Exception("Only one &rest arg can be specified");
}
ret.parameters[param++] =
new Parameter((Symbol)p, Parameter.Spec.REST, null);
++ret.numRest;
}
}
break;
}
a = a.rest;
}
return(ret);
}
