On Thu, 2012-10-25 at 13:00 -0700, bsquared wrote:
I attempted a simple test using this:
8< ------------------------------------------------
private static const Set<string> STATIC_SET;
static construct {
STATIC_SET = new HashSet<string> ();
STATIC_SET.add ("Hello");
STATIC_SET.add ("World");
}
------------------------------------------------ >8
with this result:
8< ------------------------------------------------
valac --pkg gee-1.0 hello_set.vala
hello_set.vala:5.4-5.47: error: `Gee.Set<string>' not supported as type
for constants
private static const Set<string> STATIC_SET;
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
hello_set.vala:8.3-8.16: error: The name `add' does not exist in the
context of `HelloTest.STATIC_SET'
STATIC_SET.add("Hello");
^^^^^^^^^^^^^^
hello_set.vala:9.3-9.16: error: The name `add' does not exist in the
context of `HelloTest.STATIC_SET'
STATIC_SET.add("World");
^^^^^^^^^^^^^^
Compilation failed: 3 error(s), 0 warning(s)
------------------------------------------------ >8
To my untrained eye this appears to indicate that I cannot use these as
constants. If I drop 'const' from the declaration it compiles and runs
correctly.
This is the expected result - if the Set is constant, then you can't call the add method on it. It looks like the Gee Set type simply doesn't support being used as a constant. I think that the only types that you can actually use as constants in Vala are ones that compile to basic/simple C types, and therefore could be created using constant C initializers. If you have to write data to the object at run-time to fill it, it's not a compile-time constant, after all. This limits you to using things like arrays of structures, for example. If you really want a run-time initialized Set, then it will have to be non-const. -- Calvin Walton <calvin walton kepstin ca>
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