Data Deserves a Language Too Bernard Lambeau Universit catholique de Louvain (Belgium) @blambeau csv,conf Berlin 15 July 2014

Weve got a serious marriage issue between Code and Data

You cant disentangle them when designed conjointly e.g. try sending a Java Graph abstraction over the wire to another (non Java) software Component

You cant assemble them when designed separately e.g. try solving the Impedance Mismatch in a sound and elegant way

Coupling issue known for ages Niklaus Wirth, 1976 The father of Pascal, Modula 2 and a lot more Main message Data structures and Algorithms are highly related Yields another coupling issue Between software components Hurts evolution

A solution used for ages Information Hiding Parnas, 1971 Abstract Data Types Liskov, 1974 Avoid coupling between software components Encapsulate data Access it only via behavioral interfaces e.g. the Stack ADT and its axiomatic contract

Software: a black-box cathedral ? ? ?

A Possible Root Cause Programming languages & practices have strong biases towards Behavior Type systems & Type checking algorithms APIs and documentation Testing They mostly ignore the Data perspective of engineering To be is too often sacrificed over To Behave

To Be is to be a Value that is, a member of a Type An interesting question is Are you, value v, a member of type T ? Examples Are you 13 an Integer between 0 and 45 ? Are you {} a Member information with a valid Password, that is, a String of min 8 characters ? Useful only if we can capture interesting Types in the first place Sets of values, Arbitrary Subsets, Supersets Weak or no support in conventional prog. languages

Data Deserves a Language Too What would a language strongly biased towards data look like? OR

http://www.finitio.io/try Finitio is a language for Enforcing Validating Documenting Coercing Datatypes in Files APIs Exchanges Databases + an interoperability layer: Information Contracts A proposed dual to ADTs axiomatic contracts

Meet Finitio & Contribute http://www.finitio.io/ The best starting point github.com/blambeau/finitio Language specification, e2e tests, doc source github.com/blambeau/finitio-rb Ruby binding github.com/llambeau/finitio.js Javascript binding