Overriding in module descriptors

Following an agreeable discussion about module descriptors and assemblies, we decided that we need to allow overrides in module.ceylon. Merging these overrides would apply downwards in a module dependency tree (cycles are not a problem because they always have to be compiled together anyway).

For flatclasspath we would still require additional overrides (to resolve conflicts between non-shared but duplicated dependencies).

We’d need a compile-time version validation phase (to identify diamonds), which would benefit from being able to obtain dependency information without downloading the entire module. This could be a special API for herd, or a separate artifact obtainable separately from the module itself.

[lucaswerkmeister]

dont import "this.module" 😉

[gavinking]

Some people are going to complain that ~ is not easy on their keyboard 😉

Well, TBH, I would be perfectly happy using:

• the actual annotation instead of ~ for import version overrides, and
• the shared annotation instead of ~ for import export overrides, and
• nothing instead of + for adding imports.

But then I wouldn’t know what to do for removing imports, which @FroMage insists is a necessary capability.

FTR, it would look like this:

native("jvm")
module com.my.app "1.0.0" {
    import "org.hibernate:hibernate-entitymanager" "5.0.4.Final";
    import "org.hsqldb:hsqldb" "2.3.1";
    module "org.hibernate:hibernate-entitymanager" "5.0.4.Final" {
        shared import "org.hibernate:hibernate-core";
        shared import "org.javassist:javassist";
        shared import "org.hibernate.javax.persistence:hibernate-jpa-2.1-api";
    }
    module "org.hibernate:hibernate-core" {
        shared import "javax.transaction:jta" "1.1";
    }
}

The above is rather clean and readable, and more ceylonic (no cryptic symbols). But how would you indicate removal of a dependency?