CPSCONTINUATION PASSING

STYLEWITH SCALA

CHENSE Meetup, 4/1/14

ABOUT MEPrasanna Kumar

A Java/Scala programmerfind me @prasseemail me

fork me in githubhttp://github.com/prassee

prassee dot sathian at gmail dotcom

WHAT'S COOL ABOUTCONTINUATIONS ?

"Imagine an abstraction which takes youback to a point of failure in a code sothat you can run it again" - Continuations

lets you to do this !!!!

CPSCONTINUATIONS-PASSING STYLE

"Continuation-Passing Style(CPS) is a style of programmingin which control is passedexplicitly in the form of a

continuation. It also helps theprogrammers to control theexecution flow of the program

at runtime"CPS is a functional programming techniqueScala has support for "Delimited"ContinuationsDelimited Continuation limits the scope ofContinuation in a certain boundary

CPS IN SCALAScala has two keywords for CPS - reset andshiftshift must be contained with-in reset.Since Scala supports 'delimited' CPS thescope of the code for CPS is contained within the reset block

A simple examplereset { shift { k: (Int=>Int) => // The continuation k will be the '_ + 1' below. k(7) } + 1}// Result: 8

CPS'ED FILE READING

USAGE SCENARIOSException HandlingXXX protocol handler (web frameworks !!!)BacktrackingAPI development

QUESTIONS

COURTESYHTML 5CSS 3reveal.js

THANKS :-)