//.........................................................................
public Closure(Cons args, IEnvironment env, Interpreter interpreter, Location loc)
{
InnerInterpreter = interpreter;
InnerLocation = loc;
ArgSpecs specs = AnalyzeArgSpec((Cons)args.First, env, loc);
//create an env expanded by params in which to analyze body
IEnvironment env2 = new Environment(specs.Parameters, null, env);
InnerArgsSpecs = specs;
InnerBody = interpreter.Analyze(new Cons(interpreter.BLOCK, args.Rest), env2, loc);
InnerEnvironment = env;
}
//parse out params from spec (which may contain &optional, &key, &rest, initforms etc
protected ArgSpecs AnalyzeArgSpec(Cons arglist, IEnvironment env, Location loc)
{
//count the params
int nParams = 0;
Cons a = arglist;
while (a != null) {
Object p = a.First;
if (p != InnerInterpreter.AMPOPT && p != InnerInterpreter.AMPKEY && p != InnerInterpreter.AMPREST)
++nParams;
a = a.Rest;
}
ArgSpecs ret = new ArgSpecs(env);
ret.Parameters = new Parameter[nParams];
Parameter.Specification state = Parameter.Specification.REQ;
int param = 0;
a = arglist;
while (a != null) {
Object p = a.First;
switch (state) {
case Parameter.Specification.REQ:
if (p == InnerInterpreter.AMPOPT)
state = Parameter.Specification.OPT;
else if (p == InnerInterpreter.AMPKEY)
state = Parameter.Specification.KEY;
else if (p == InnerInterpreter.AMPREST)
state = Parameter.Specification.REST;
else {
if (p is Symbol) {
ret.Parameters[param++] =
new Parameter((Symbol)p, Parameter.Specification.REQ, null);
++ret.NumReq;
} else if (p is Cons) {
ret.Parameters[param] =
new Parameter((Symbol)((Cons)p).First, Parameter.Specification.REQ, null);
ret.Parameters[param].TypeSpec = InnerInterpreter.Eval(Cons.GetSecond((Cons)p), env);
++param;
++ret.NumReq;
}
}
break;
case Parameter.Specification.OPT:
if (p == InnerInterpreter.AMPOPT)
throw new LispException("&optional can appear only once in arg list");
else if (p == InnerInterpreter.AMPKEY)
state = Parameter.Specification.KEY;
else if (p == InnerInterpreter.AMPREST)
state = Parameter.Specification.REST;
else {
if (p is Symbol) {
ret.Parameters[param++] =
new Parameter((Symbol)p, Parameter.Specification.OPT, null);
++ret.NumOpt;
} else if (p is Cons) {
ret.Parameters[param++] =
new Parameter((Symbol)((Cons)p).First, Parameter.Specification.OPT,
InnerInterpreter.Analyze(Cons.GetSecond((Cons)p), env, loc));
++ret.NumOpt;
} else
throw new LispException("&optional parameters must be symbols or (symbol init-form)");
}
break;
case Parameter.Specification.KEY:
if (p == InnerInterpreter.AMPOPT)
throw new LispException("&optional must appear before &key in arg list");
else if (p == InnerInterpreter.AMPKEY)
throw new LispException("&key can appear only once in arg list");
else if (p == InnerInterpreter.AMPREST)
state = Parameter.Specification.REST;
else {
if (p is Symbol) {
ret.Parameters[param] =
new Parameter((Symbol)p, Parameter.Specification.KEY, null);
ret.Parameters[param].Key = InnerInterpreter.Intern(":" + ((Symbol)p).Name);
++param;
++ret.NumKey;
} else if (p is Cons) {
ret.Parameters[param] =
new Parameter((Symbol)((Cons)p).First, Parameter.Specification.KEY,
InnerInterpreter.Analyze(Cons.GetSecond((Cons)p), env, loc));
ret.Parameters[param].Key =
InnerInterpreter.Intern(":" + ((Symbol)((Cons)p).First).Name);
++param;
++ret.NumKey;
} else
throw new LispException("&key parameters must be symbols or (symbol init-form)");
}
break;
case Parameter.Specification.REST:
if (p == InnerInterpreter.AMPOPT)
throw new LispException("&optional must appear before &rest in arg list");
else if (p == InnerInterpreter.AMPKEY)
throw new LispException("&key must appear before &rest in arg list");
else if (p == InnerInterpreter.AMPREST)
throw new LispException("&rest can appear only once in arg list");
else {
if (!(p is Symbol))
throw new LispException("&rest parameter must be a symbol");
else {
if (ret.NumRest > 0) //already got a rest param
throw new LispException("Only one &rest arg can be specified");
ret.Parameters[param++] =
new Parameter((Symbol)p, Parameter.Specification.REST, null);
++ret.NumRest;
}
}
break;
}
a = a.Rest;
}
return ret;
}