Created
February 17, 2011 02:43
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Lazy evaluation of closures during object construction
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scala> def test = { println("Evaluating"); "test" } | |
test: java.lang.String | |
scala> case class TestClass(s: String) { override def toString = "overrided so the REPL doesn't coerse evaluation of s" } | |
defined class TestClass | |
scala> val t = TestClass(test) | |
Evaluating | |
t: TestClass = overrided so the REPL doesn't coerse evaluation of s | |
scala> // Construction of TestClass has evaluated s attribute | |
scala> trait TestTrait { def s: String } | |
defined trait TestTrait | |
scala> val t = new TestTrait { lazy val s = test } | |
t: java.lang.Object with TestTrait = $anon$1@4b3ca972 | |
scala> // Construction of TestTrait instance has not evaluated s attribute | |
scala> t.s | |
Evaluating | |
res1: String = test | |
scala> t.s | |
res2: String = test | |
scala> // Second call for s attribute doesn't reevaluate | |
scala> |
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