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icejoywoo/InterpolationDemo.scala

Last active April 26, 2019 16:32
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create case class using string interpolation
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InterpolationDemo.scala
import com.twitter.util.Eval
object InterpolationDemo {
case class Indicator(basetime: String, key: String, value: Double)
case class ExprImplicit(basetime: String, data: Map[String, Double])
implicit class IndicatorExpressionHelper(val sc: StringContext) extends AnyVal {
def indicator(args: Any*)(implicit default: ExprImplicit): Indicator = {
val strings = sc.parts.iterator
val expressions = args.iterator
var basetime: Option[String] = None
var key: String = null
var value: Double = -1
val env = default.data.map{ case (k, v) => s"val $k = $v" }.mkString("\n")
while (strings.hasNext && expressions.hasNext) {
val k = strings.next.trim.stripPrefix(",").stripSuffix(":").trim
val v = expressions.next
k match {
case "basetime" =>
basetime = Some(v.toString)
case "key" =>
key = v.toString
case "value" =>
val eval = new Eval
val expr = s"""$env
|${v.toString}
|""".stripMargin
try {
value = eval[Double](expr)
} catch {
case e: com.twitter.util.Eval.CompilerException =>
println(s"key[$key] expr[${expr.split("\n").mkString("; ")}] exception[${e.getMessage}]")
}
case _ =>
println(v)
}
}
if (strings.nonEmpty && strings.next.nonEmpty) {
println("error: " + strings.next)
}
if (expressions.nonEmpty) {
println("error: " + expressions.next)
}
if (basetime.isDefined) {
Indicator(basetime.get, key, value)
} else {
Indicator(default.basetime, key, value)
}
}
}
def main(args: Array[String]): Unit = {
val basetime = "2019042805"
implicit val expr = ExprImplicit(basetime, Map("a" -> 50, "b" -> 2300, "c" -> 230))
println((indicator"basetime: $basetime, key: ${"ratio_1"} , value: ${"a/b"}"))
println((indicator"basetime: ${"2019043009"}, key: ${"ratio_2"} , value: ${"c/b"}"))
println((indicator"key: ${"ratio_1"} , value: ${"a/b"}"))
println((indicator"key: ${"ratio_1"} , value: ${"d/b"}"))
}
}
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icejoywoo commented Apr 26, 2019 •
edited
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<dependency>
    <groupId>com.twitter</groupId>
    <artifactId>util-eval_2.11</artifactId>
    <version>6.43.0</version>
</dependency>

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