Type Checking - Introduction to Compiler Construction in a Java World - page 155

}
returnresult;
}
For example, consider the following message expression:
java.lang.System.out.println(...);
The parser will have encapsulated the target java.lang.System.out in an AmbiguousName
object. The first thing analyze() does for a JMessageExpression is to reclassify this
AmbiguousName to determine the structure of the expression that it denotes. It does this by
looking at the ambiguous java.lang.System.out from left to right.
1. First, reclassify( ) looks up the simple name java in the symbol table.
2. Not finding that, it looks up java.lang .
3. Not finding that, it looks up java.lang.System , which (assuming java.lang.System
has been properly imported) it finds to be a class.
4. It then assumes that the rest of the ambiguous part, that is out , is a field.
5. Thus, the target is a field selection whose target is java.lang.System and whose field
name is out .
Analyzing a Field Selection
The code for analyzing a field is as follows:
publicJExpressionanalyze(Contextcontext){
//Reclassifytheambiguouspart.
target=(JExpression)target.analyze(context);
TypetargetType=target.type();
//Weuseaworkaroundforthe"length"fieldofarrays.
if((targetTypeinstanceofArrayTypeName)
&&fieldName.equals("length")){
type=Type.INT;
}else{
//Otherthanthat,targetTypehastobea
//ReferenceType
if(targetType.isPrimitive()){
JAST.compilationUnit.reportSemanticError(line(),
"Targetofafieldselectionmust"
+"beadefinedtype");
type=Type.ANY;
returnthis;
}
field=targetType.fieldFor(fieldName);
if(field==null){
JAST.compilationUnit.reportSemanticError(line(),
"Cannotfindafield:"+fieldName);
type=Type.ANY;
}else{
context.definingType().checkAccess(line,
(Member)field);
type=field.type();
//Non-staticfieldcannotbereferencedfroma
//staticcontext.
if(!field.isStatic()){