Lisaac

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Lisaac
Paradigm object-oriented prototype-based
Appeared in 2003
Designed by Benoît Sonntag
Developer Benoît Sonntag & Jérôme Boutet
Latest release 0.12/ September 24, 2007
Typing discipline static typing
Major implementations Lisaac
Influenced by Smalltalk, Self, Eiffel
Website isaacproject.u-strasbg.fr

Lisaac is the first compiled object-oriented programming language based on prototype concepts, with system programming facilities and design by contract.

Lisaac's developers admired both Self's flexibility and dynamic inheritance, and Eiffel's static typing and design by contract features. Seeking to combine these two apparently contradictory feature sets, Lisaac was created.

Lisaac was designed as the language in which the Isaac operating system would be programmed.

The Lisaac compiler produces optimized ANSI C code, which can then be compiled on every architecture with an appropriate C compiler which makes Lisaac a real multi-platform language. Compiling results show that it is possible to obtain executables from a high-level prototype-based language that are as fast as C programs[1].

Despite being strongly typed, there is no difference between code and data.

Contents

[edit] Features

  • Communication protection mechanisms
  • Hardware facilities
    • System interrupt support
    • Driver memory mapping
  • Despite being compiled, all objects retain their dynamic abilities

[edit] Dynamic inheritance

The parent of each object is just a slot that can be assigned as required in the code, for instance:

- NAME := DECOD_MPEG2_TO_SCREEN

section INHERIT

- videoparent : OBJECT <- 
( 
  + result : OBJECT;

 typ 
 .when 1 then { result := WINDOW;} 
 .when 2 then { result := VIDEO_VGA;} 
 .when 3 then { result := VIDEO_TVOUT;};

 result 
) 

section PUBLIC

- typ : INTEGER;

- decode_flux <-

( 
 putimage decode_to_bitmap; 
)

[edit] Operator redefining

In Lisaac, an operator is a slot and can be redefined. For example overloading the + operator for a NUMERIC object:

- '+'  left 80  other:SELF :SELF <- self - -other;

Or for a matrix:

- '+'  left 80  other:SELF :SELF <- 

(
        + result : SELF; 

        result := SELF.create count; 
        1.to tab.count do { 
                        i : INTEGER; 
                result.put (item i+other.item i) to i; 
        };

        result
)

[edit] Genericity

Generic objects are supported, for instance:

ARRAY[E], DICTIONARY[KEY,VALUE]

[edit] Contract programming

Contract programming using Z notation is provided.

[edit] External links

[edit] Notes and references

  1. ^ Isaac project benchmarks. Retrieved on 2007-07-24.


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