Description Hallvard Traetteberg 2011-05-02 05:31:20 EDT

I wanted to traverses up a chain of Package objects, to compute the full name, and tried the following:

[query public packageFullName(pack : Package, suffix : String) : String =
    if pack.oclIsUndefined() then suffix else packageFullName(pack._package, pack.name + '.' + suffix) endif
/]

If called on a chain of packages with names org.eclipse.tests it returns <undefined-object>.org.eclipse where <undefined-object> is the result of calling oclUndefined.toString(). It is as if the pack.name expression in pack.name + '.' + suffix is interpreted as pack._package.name.

However, the following works:

[query public packageFullName(pack : Package, suffix : String) : String =
    if pack.oclIsUndefined() then suffix else let suffix : String = pack.name + '.' + suffix in packageFullName(pack._package, suffix) endif
/]

I.e. the argument is computed before the recursive call to packageFullName. I cannot understand why the result should differ and be wrong in the first case.