internal Closure(Cons args,Env env,Interpreter interpreter,Loc loc)
{
this.interpreter = interpreter;
this.loc = loc;
ArgSpecs specs = analyzeArgSpec((Cons)args.first,env,loc);
//create an env expanded by params in which to analyze body
Env env2 = new Env(specs.parameters, null, env, interpreter);
this.argSpecs = specs;
this.body = interpreter.analyze(new Cons(interpreter.BLOCK,args.rest), env2,loc);
this.env = env;
}
internal BacktraceFrame(Loc loc,Object f,Object args)
{
if(loc != null)
{
this.file = loc.file;
this.line = loc.line;
}
else
{
this.file = "no file";
this.line = 0;
}
this.f = f;
this.args = args;
}
internal ApplyExpression(Cons args,Env env,Interpreter interpreter,Loc loc)
{
this.loc = loc;
this.interpreter = interpreter;
fexpr = interpreter.analyze(args.first,env,loc);
if(fexpr is IVar)
{
fsym = ((IVar)fexpr).getSymbol();
}
Int32 len = Cons.Length(args.rest);
argexprs = new IExpression[len];
args = args.rest;
for(Int32 i=0;i<argexprs.Length;i++,args = args.rest)
{
argexprs[i] = interpreter.analyze(args.first,env,loc);
}
}
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);
}
internal Object Load(LocTextReader t)
{
Object expr = null;
do
{
Int32 line = t.line;
expr = Read(t);
if(!Eof(expr))
{
try
{
eval(expr,globalenv);
}
catch(Exception ex)
{
Loc loc = new Loc(t.file, line);
Console.Error.WriteLine(ex);
Console.Error.WriteLine("loc=" + loc);
Console.ReadLine();
throw BacktraceException.push(ex,
new BacktraceFrame(loc, "when evaluating ", expr), this);
}
}
}while(!Eof(expr));
return true;
}
internal Object ReadVector(params Object[] args)
{
LocTextReader t = (LocTextReader)args[0];
Int32 line = t.line;
Cons largs = readDelimitedList(t,']');
Object ret = new Cons(interpreter.VECTOR,largs);
//record the location
locTable[ret] = new Loc(t.file,line);
return ret;
}
internal Object ReadUnquote(params Object[] args)
{
LocTextReader t = (LocTextReader)args[0];
Int32 line = t.line;
Int32 ch = t.Peek();
Object ret = null;
if(ch == '@')
{
t.Read();
ret = Cons.MakeList(interpreter.UNQUOTE_SPLICING,doRead(t,false));
}
else
ret = Cons.MakeList(interpreter.UNQUOTE,doRead(t,false));
//record the location
locTable[ret] = new Loc(t.file,line);
return ret;
}
internal Object ReadString(params Object[] args)
{
StringBuilder b = new StringBuilder();
LocTextReader t = (LocTextReader)args[0];
Int32 line = t.line;
//eat the double-quote
//t.Read();
//Int32 ch = t.Peek();
Int32 ch = t.Read();
while(ch != '"')
{
if(ch == -1)
{
throw new Exception("Read error - eof found before matching: \""
+ "\n File: " + t.file + ", line: " + t.line);
}
//eat it
//t.Read();
if(ch == '\\') //escape
{
ch = t.Read();
if(ch == -1)
{
throw new Exception("Read error - eof found before matching: \""
+ "\n File: " + t.file + ", line: " + t.line);
}
switch(ch)
{
case 't':
ch = '\t';
break;
case 'r':
ch = '\r';
break;
case 'n':
ch = '\n';
break;
case '\\':
break;
case '"':
break;
default:
throw new Exception("Unsupported escape character: \\" + (Char)ch
+ "\n File: " + t.file + ", line: " + t.line);
}
}
b.Append((Char)ch);
//ch = t.Peek();
ch = t.Read();
}
//eat the trailing quote
//t.Read();
Object ret = b.ToString();
//record the location
locTable[ret] = new Loc(t.file,line);
return ret;
}
internal Object ReadQuote(params Object[] args)
{
LocTextReader t = (LocTextReader)args[0];
Int32 line = t.line;
Object ret = Cons.MakeList(interpreter.QUOTE,doRead(t,false));
//record the location
locTable[ret] = new Loc(t.file,line);
return ret;
}
internal Macro(Cons args,Env env,Interpreter interpreter,Loc loc)
:base(args,env,interpreter,loc)
{
}
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 OrExpression(Cons args,Env env,Interpreter interpreter,Loc loc)
{
this.loc = loc;
this.interpreter = interpreter;
exprs = new IExpression[Cons.Length(args)];
for(Int32 i=0;i<exprs.Length;i++,args = args.rest)
{
exprs[i] = interpreter.analyze(args.first,env,loc);
}
}
internal WhileExpression(Cons args,Env env,Interpreter interpreter,Loc loc)
{
this.loc = loc;
this.interpreter = interpreter;
this.test = interpreter.analyze(args.first,env,loc);
this.body = interpreter.analyze(new Cons(interpreter.BLOCK,args.rest),env,loc);
}
internal DynamicLet(Cons args,Env env,Interpreter interpreter,Loc loc)
{
this.loc = loc;
this.interpreter = interpreter;
Cons bindlist = (Cons)args.first;
Int32 blen = Cons.Length(bindlist);
if((blen%2) != 0) //odd
{
throw new Exception("Odd number of args in dynamic-let binding list");
}
binds = new BindPair[blen/2];
for(int i = 0;i<binds.Length;i++)
{
binds[i].dvar = (DynamicVar)interpreter.analyze(bindlist.first, env,loc);
bindlist = bindlist.rest;
binds[i].expr = interpreter.analyze(bindlist.first, env,loc);
bindlist = bindlist.rest;
}
this.body = interpreter.analyze(new Cons(interpreter.BLOCK,args.rest), env,loc);
}
internal DynamicLet(Cons args,Env env,Interpreter interpreter,Loc loc)
{
this.loc = loc;
this.interpreter = interpreter;
Cons bindlist = (Cons)args.first;
Int32 blen = Cons.Length(bindlist);
if((blen%2) != 0) //odd
{
throw new Exception("Odd number of args in dynamic-let binding list");
}
binds = new BindPair[blen/2];
for(int i = 0;i<binds.Length;i++)
{
// MEH: Better error instead of InvalidCastException
//binds[i].dvar = (DynamicVar)interpreter.analyze(bindlist.first, env,loc);
if((binds[i].dvar = (interpreter.analyze(bindlist.first, env,loc) as DynamicVar)) == null)
throw new Exception("Dynamic vars must have prefix *");
bindlist = bindlist.rest;
binds[i].expr = interpreter.analyze(bindlist.first, env,loc);
bindlist = bindlist.rest;
}
this.body = interpreter.analyze(new Cons(interpreter.BLOCK,args.rest), env,loc);
}
//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;
}
internal Object ReadList(params Object[] args)
{
LocTextReader t = (LocTextReader)args[0];
Int32 line = t.line;
Object ret = readDelimitedList(t,')');
//record the location
if(ret != null)
locTable[ret] = new Loc(t.file,line);
return ret;
}
