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

2. We’ve got
a serious
marriage issue
between
Code and Data

3. You can’t
disentangle
them when
designed
conjointly
e.g. try sending a Java Graph abstraction over the wire
to another (non Java) software Component

4. You can’t
assemble
them when
designed
separately
e.g. try solving the Impedance Mismatch
in a sound and elegant way

5. 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

6. 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

7. Software: a black-box cathedral
?
?
?

8. 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

9. 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

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

11. 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

12. 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