Groovy : why this code doesn't work ? unable to resolve class

Question

I have this test code:

def p = [:]

p.foo = [:]

p.foo.bar = 120

p.foo.bar - 3

(p.foo.bar) + 3

why on the last statement i get a compilation error : "unable to resolve class p.foo.bar "?

Thanks for the help

Groovy version 1.8.1

Wow, that is weird. Oddly, this works: (p.foo).bar + 3. I also tried using classes with defined properties instead, but got the same error! It looks like putting it in parentheses like that causes it to look for a package called p.foo with a class called bar. — OverZealous
– OverZealous, Commented Oct 31, 2011 at 4:58

OverZealous · Accepted Answer · 2011-10-31 05:12:27Z

3

OK, I think I figured it out. I ran the AST browser against your sample script (using the GroovyConsole). It would only show an output at the Conversion phase. At this phase you can see how the script is converted. The key is that the last line is converted into this:

...
((1) as p.foo.bar)

This means that, apparently, it's trying to cast or convert the 1 into a class named p.foo.bar.

You can dig a little deeper and see that the parser is parsing the statement like this:

(p.foo.bar)(+1)

Which is the same as

(p.foo.bar)1

Therefore, the parser/compiler is seeing the + as a unary + operator. And that is why you are getting the error. (The way around it it to remove the parentheses, or swap the order of the arguments!)

answered Oct 31, 2011 at 5:12

OverZealous

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2 Comments

res1 Over a year ago

Do you consider this behaviour of the compiler/parser right or like an error/bug?

OverZealous Over a year ago

Unexpected, maybe, but definitely not a bug. Wrapping a single class is a standard way to cast. I don't see how this would ever be written this way normally, either.

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