PROGRAMme
Notations: There is no escape

PROGRAMme (leading auhtors: Troy Astarte, Maarten Bullynck, Felice Cardone, Martin Carlé, Liesbeth De Mol, Marie-José Durand-Richard,
Tomas Petricek, Mark Priestley, Henri Salha)

Perlman's button box
Programmable or not?

1) Buttons control turtle 2) "Memory box" buttons 3) Kid interface for LOGO






machine ⟷ human






machine ⟷ notation ⟷ human

Meaning of notations

Negotiation of meaning

  • Machine and human "understanding" differ
  • Different users have different needs
  • Meaning found in operational structure

High programmability

  • Potential to establish new meaning
  • Allows "meaningful" programming

Blind computation

Blind computation

19th century English algebraists

  • \(\sqrt{a-b}\) only defined if \(a\geq b\)
  • Independence from arithmetic
  • Terms "general in form and value"

20th century mathematical logic

  • Tackle decidability problems
  • Mechanical rule following

Operational meaning

Meaning in blind computation

  • Establishes analogies
    that reveal new patterns

Reverse Polish notation

  • Example: 3 2 + 5 4 2 * + *
  • Notation matches evaluator!

Surprise of programming

Electronic speed

[C]ontemplate the prospect of locking twenty people for two years during which they would be steadily performing computations. And you must give them such explicit instructions at the time of incarceration that at the end of two years you could return and obtain the correct result for your lengthy problem! (John von Neumann)

Notations for humans

Flowcharts

  • John von Neumann for EDVAC
  • Translated manually to instructions

Interpretive subroutines

  • Wilkes et al. for EDSAC
  • Symbolic codes
  • Executed by initial orders

Opening of Pandora's box

Many notations solving:

1) Problem of control
2) User problem
3) Effectiveness problem

Closing of Pandora's box

Like surrealist "exquisite corpse" drawings!

1) Automatic programming
2) Universal language
3) Self-programmability
4) Concrete notations

1) Automatic programming
High-level notations...
Could there be just one?

2) Universal language
One language is not enough
Could it be adaptable?

3) Self-programmability
System as meta-medium
Uses direct representation

4) Concrete notations
Focus on directness
No need for generality...

Self-programmability

LISP

  • Recursion & programs as data
  • Adaptable meta-notation
  • Time-sharing and IBM 704

Smalltalk

  • Objects represent real things
  • Programmable meta-medium
  • Recursion on the notion of computer

There is no escape

There is no escape

No-code programming

  • Programming for end-users
  • Visual and UI is also notation
  • Low notational programmability

Automatic programming, revisited

  • AI that "understands" human language
  • No negotiation of meaning
  • Human is programmed!

PROGRAMme
Notations: There is no escape



Conclusions

If we want meaningful programming

We get notational pluralism

Ideally with high notational programmability