I'm using the ANTLR v4 Java grammar, available here, to parse Java code. One of the productions looks like this:
expression
: primary
| expression '.' Identifier
| expression '.' 'this'
| expression '.' 'new' nonWildcardTypeArguments? innerCreator
| expression '.' 'super' superSuffix
| expression '.' explicitGenericInvocation
| expression '[' expression ']'
| expression arguments
| // Lots of other patterns...
;
expression '.' Identifier matches a simple member access, and expression arguments matches a method call. You can view the full source of this production here.
For the purposes of syntax highlighting, I want to introduce additional redundant patterns to detect what I call named method invocations. bar() or foo.bar() would count as a named method invocation, with bar being the name of the method. For such expressions I want bar to be colored green, even though identifiers are normally colored white. However, in foo.bar or foo.bar[0](), nothing should be colored green. In the former bar is not calling a method, and in the latter bar[0] is not a valid identifier.
I added these two extra patterns before expression arguments (note: arguments is synonymous with '(' expressionList? ')' in the original source code):
expression
: // ...
| expression '[' expression ']'
| Identifier arguments namedMethodInvocationStub // Detect bar()
| expression '.' Identifier arguments namedMethodInvocationStub // Detect (some().complicated().expression()).bar()
| expression arguments
| // ...
;
namedMethodInvocationStub
:
;
(Here, namedMethodInvocationStub is an extra dummy production I've added. The idea is I can override VisitExpression and check if the last child is a namedMethodInvocationStub. If so, then we've matched a named method invocation, so go through all direct children of type Identifier and color them green. Anyhow, this is just to demystify what that is, it's not directly related to my question below.)
I expected this rule change to make foo.bar(), which had previously parsed as (expression '.' Identifier) arguments, now parse as expression '.' Identifier arguments namedMethodInvocationStub. However, it still parses the same way as before, whether or not I remove the namedMethodInvocationStub. Why is this?
