http://scalamatsuri.org/

1. ScalaMatsuri 2014 LT
Short introduction of
Implicit Conversion
Sep. 6, 2014.
Atsushi Oku
TIS Inc.
Copyright © 2014 TIS Inc. All rights reserved.

2. About Me
• Programming in Java over 15 years
• A member of R&D Division
(Strategic Technology Center)
• Joined in our Scala research project in Mar. ‘14
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3. About this LT
• I participated in Scala training courses offered by
Typesafe Inc.
– “Fast track to Scala” / “Advanced Scala”
• Through these trainings, I become to like
"Implicit Conversion" (and DSL) feature.
• So I ’ll try to introduce this feature and small
sample codes.
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4. About training courses
• http://typesafe.com/how/trainings
• Some courses can be participated from
anywhere in the world "virtually"
– even if you are at home in Japan
– by using webcam, headset and VNC software
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5. Implicit Conversion
• Why no error?
`1’ (Int) doesn’t have `->’ method
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6. Implicit Conversion
• If compiler find a type error,
the compiler looks for implicit
conversion.
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7. When does compiler look for ...
Type mismatch  looking for implicit
conversion to the excepted type
(from Double to Int)
Receiver 'Int' doesn’t have `->' method
 looking for implicit conversion
of the receiver (from Int to X which has
`->' method)
Ex1
Ex2
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8. Define Implicit Conversion
• Any method name is OK
• Implicit conversion has to be in scope
in order to be applied.
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9. Add new method to existing class
• New method `sub' is added to Int !
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10. Implicit class
• Since Scala 2.10, `implicit class' is available
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11. My First DSL
• My simple Date class is like this
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• I'd like to write codes in my DSL like this

12. My First DSL
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13. Please join our colleague's presentation
A-4 14:50 – 15:30
Scalable Generator: Using Scala in SIer Business
SIerに立ちはだかるScalaの壁に進化型ジェネレータで挑む
- TIS Yugo Maede
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14. THANK YOU