/*
* (non-Javadoc)
*
* @see jaskell.compiler.JaskellVisitor#visit(jaskell.compiler.core.Module)
*/
public Object visit(Namespace a) {
/* set current namespace */
ns = a;
/*
* visit definitions We set an infinite loop to cope with modifications
* introduced by visiting sub expressions. When something is modified -
* through lift - we restart the whole process. TODO : change this to defer
* registering new bindings at end
*/
while (true) {
try {
Iterator it = a.getAllBindings().entrySet().iterator();
while (it.hasNext()) {
Map.Entry entry = (Map.Entry) it.next();
String functionName = (String) entry.getKey();
Expression def = (Expression) entry.getValue();
if (def instanceof Abstraction)
((Abstraction) def).setClassName(ns.getName() + "." + functionName);
log.finest("Analyzing lifting for " + functionName);
lift = false;
entry.setValue((Expression) def.visit(this));
}
break;
} catch (ConcurrentModificationException cmex) {
/* restart the process */
}
}
return a;
}
/**
* Returns null or throws a TypeError if type cannot be inferred for any definition found.
* Verifies that main symbol in Main module is typed as <code>IO ()</code>.
*
* @see jaskell.compiler.JaskellVisitor#visit(Module)
*/
public Object visit(Namespace a) {
// visit definitions
Iterator it = a.getAllBindings().entrySet().iterator();
while (it.hasNext()) {
Map.Entry entry = (Map.Entry) it.next();
String name = (String) entry.getKey();
Expression def = (Expression) entry.getValue();
Type type = (Type) def.visit(this);
def.setType(type);
log.finer("TypeChecker => END Visiting " + name);
}
log.finer("Substitution map = " + typeVariablesMap);
return null;
}
/*
* Definitions in the let block are lifted to top-level and the corresponding
* references in the body are replaced by new definitions.
*
* @see jaskell.compiler.JaskellVisitor#visit(jaskell.compiler.core.Let)
*/
public Object visit(Let let) {
HashMap subst = new HashMap(); /* substitution map */
Set lambdas = new HashSet(); /* newly created toplevels ? */
Iterator it = let.getBindings().entrySet().iterator();
/* first lift all definitions in this let */
while (it.hasNext()) {
Map.Entry entry = (Map.Entry) it.next();
String name = (String) entry.getKey();
Expression e = (Expression) entry.getValue();
/* reset lift flag */
lift = false;
Expression ndef = (Expression) e.visit(this);
ndef.setParent(let);
/* lift new definition */
Set captured = new HashSet();
CaptureCollector cc = new CaptureCollector(captured);
ndef.visit(cc);
String vname;
try {
vname = lift(ndef, captured);
lambdas.add(vname);
/*
* store new application spine in a map for later substitution
*/
subst.put(name, applyLifted(vname, captured));
} catch (SymbolException e1) {
e1.printStackTrace();
}
}
/* second, replace old occurences in new definitions */
it = lambdas.iterator();
while (it.hasNext()) {
String n = (String) it.next();
Expression e;
try {
e = (Expression) ns.resolve(n);
ns.rebind(n, (Expression) e.visit(new Substitution(subst)));
} catch (SymbolException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
}
/* thirs, replace occurences in body of let and return it */
return let.getBody().visit(new Substitution(subst));
}
/** @see jaskell.compiler.JaskellVisitor#visit(Let) */
public Object visit(Let a) {
Type ret = a.getType();
if (ret != null) return ret;
// visit definitions
Iterator it = a.getBindings().entrySet().iterator();
while (it.hasNext()) {
Map.Entry entry = (Map.Entry) it.next();
String name = (String) entry.getKey();
Expression def = (Expression) entry.getValue();
log.finer("Visiting " + name);
def.setType((Type) def.visit(this));
}
// visit body
ret = (Type) a.getBody().visit(this);
a.setType(ret);
// return type of body
return ret;
}
/** @see jaskell.compiler.JaskellVisitor#visit(Alternative) */
public Object visit(Alternative a) {
try {
Type tex = (Type) a.getExpression().visit(this);
log.finer("In alternative, type of expression " + a.getExpression() + " is " + tex);
/* set type of bound variable */
LocalBinding lb = a.getBinding();
if (lb != null) lb.setType(tex);
/* visit type of alternatives */
Iterator it = a.getChoices();
Type ptype = tex;
Type btype = null;
while (it.hasNext()) {
Map.Entry entry = (Map.Entry) it.next();
/* checkt type of pattern */
Type pt = (Type) ((Pattern) entry.getKey()).visit(this);
if (ptype == null) ptype = pt;
else ptype = tu.unify(pt, ptype, typeVariablesMap);
log.finer("In alternative, unifying pattern type " + pt + " to " + ptype);
Expression expr = (Expression) entry.getValue();
/* check type of body */
Type bt = (Type) expr.visit(this);
// /* apply substitution with type variables from pattern */
// TypeSubstitution ts = new TypeSubstitution(typeVariablesMap);
// expr.visit(ts);
if (btype == null) btype = bt;
else btype = tu.unify(bt, btype, typeVariablesMap);
log.finer("In alternative, unifying body type " + bt + " to " + btype);
}
/* visit default choice */
Type deft = (Type) a.getWildcard().visit(this);
a.setType(btype);
return btype;
} catch (TypeError te) {
if (te.getLineCol() == null) te.setLineCol(a.getTag("source"));
throw te;
}
}