Let's discuss the following code:
given ($foo) {
when (@blah) { }
default { }
}
I would have thought that given would be a compound statement (especially in the face of the ability to use when/default in foreach loops); however, perlsyn does not include it in its list of compound statements, so it sounds like we'd need a new subclass of Statement for it. (Also, this would help differentiation in Perl::Critic, especially in the determination of whether a specific Policy applies to an Element.) Or we could ignore perlsyn's omission and treat it as Compound.
Should the parentheses be a Structure::Condition? Or something analogous to Structure::ForLoop? (Again, from the P::C perspective, having a new class would be better.)
Then, the when/default. The actual statements, like the given, could be Statement::Compound instances, and the parentheses after when could just be Conditions again. Even if there's a new class, the when and default could be instances of the same one, since perlsyn says that default is precisely equivalent to "when (1 == 1) { ... }".
So, ignoring whitespace tokens, as I see it, here's the most conservative way of this parsing:
PPI::Document
PPI::Statement::Compound
PPI::Token::Word 'given'
PPI::Structure::Condition ( ... )
PPI::Statement::Expression
PPI::Token::Symbol '$foo'
PPI::Structure::Block { ... }
PPI::Statement::Compound
PPI::Token::Word 'when'
PPI::Structure::Condition ( ... )
PPI::Statement::Expression
PPI::Token::Symbol '@blah'
PPI::Structure::Block { ... }
PPI::Statement::Compound
PPI::Token::Word 'default'
PPI::Structure::Block { ... }
OTOH, here's the most favorable structure from P::C's perspective (modulo the class names changing):
PPI::Document
PPI::Statement::Switch
PPI::Token::Keyword 'given'
PPI::Structure::Given ( ... )
PPI::Statement::Expression
PPI::Token::Symbol '$foo'
PPI::Structure::Block { ... }
PPI::Statement::When
PPI::Token::Keyword 'when'
PPI::Structure::Match ( ... )
PPI::Statement::Expression
PPI::Token::Symbol '@blah'
PPI::Structure::Block { ... }
PPI::Statement::When
PPI::Token::Keyword 'default'
PPI::Structure::Block { ... }
Yes, I'm thinking of trying to implement this. First, I need to figure out the parser and see whether I can fix some existing parsing problems.
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