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package dotty.tools.dotc
package transform
import core.Contexts.Context
/** Utility class for lazy values whose evaluation depends on a context.
* This should be used whenever the evaluation of a lazy expression
* depends on some context, but the value can be re-used afterwards
* with a different context.
*
* A typical use case is a lazy val in a phase object which exists once per root context where
* the expression intiializing the lazy val depends only on the root context, but not any changes afterwards.
*/
class CtxLazy[T](expr: Context => T) {
private var myValue: T = _
private var forced = false
def apply()(implicit ctx: Context): T = {
if (!forced) {
myValue = expr(ctx)
forced = true
}
myValue
}
}
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