annotated imports
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Annotated import
SIP - ???
http://bit.ly/TLZYKb
https://github.com/rssh/scala-annotated-import-example
Annotated import
Problem:Imports not composable
Set of implicit variables often configured through import.
SolutionAllow annotations before import statement
@exported import x._ => export x and all exported imports inside one.
Problem Example:
File Aimport com.mongodb.casbah.Imports._
import com.novus.salat._
import com.mycompany.salatcontext._
..............
File B import com.mongodb.casbah.Imports._
import com.novus.salat._
import com.novus.salat.global._
.................
Problem Example:
File Aimport com.mongodb.casbah.Imports._
import com.novus.salat._
import com.mycompany.salatcontext._
..............
File B import com.mongodb.casbah.Imports._
import com.novus.salat._
import com.novus.salat.global._
.................
Proposed Solution
Allow annotations before import
@exported import X._Members of X
@exported imports from X:
Proposed solution
package com.mycompany package object mongo {@exported import com.mongodb.casbah.Imports.@exported import com.novus.salat._@exported import com.mycompany.salatcontext._
}
File A: import com.mycompany.mongo._
File B:import com.mycompany.mongo._
Application module config:
package object my.app{@exported import all.required.libraries
@exported import language._
// disable some annotations
class unchecked extends Annotation {}
}
Common usage patterns:
Application writers: encapsulate all external dependencies in one package object
Library writers:Don't use, provide one module which application writers will use.
Import via inheritance:
X should exported imports in X be visible in Y trait X{ @exported import something.Interesting}
trait Y { .. use something.Interesting }
Import via inheritance
PROPeople actually emulate this approach by defining aliases for imported methods in traits.
CONTRAComplexity, ... impossible to disable simple.(provide own imports instead exported will work)
Implementation
CompilerCore, Scaladoc, Tests,
(new SIP-18 style implicit ?)
ReflectionClassfile format
Symbols/Tree API
Implementation
https://github.com/rssh/scalaBranch annotated-import
https://github.com/rssh/scala-annotated-import-example(scala-annotated-import-example)
StateCore : mostly done
Scaladoc: in progress
What needed:
Pre-SIP reviewhttp://bit.ly/TLZYKb
Examples of usage(just fork scala-import-annotations-example)
Welcome to hack.
Related things
@deprecated import ....(add warning, should not be hard)
@generated(generator) importMacros API ?
Thanks
Ruslan Shevchenko
https://github.com/rssh/
@rssh1