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Lustre (programming language)
View on Wikipedia| Lustre | |
|---|---|
| Paradigms | Dataflow, declarative, synchronous |
| First appeared | 1980s |
Lustre is a formally defined, declarative, and synchronous dataflow programming language for programming reactive systems. It began as a research project in the early 1980s. A formal presentation of the language can be found in the 1991 Proceedings of the IEEE.[1] In 1993 it progressed to practical, industrial use in a commercial product as the core language of the industrial environment SCADE, developed by Esterel Technologies. It is now used for critical control software in aircraft,[2] helicopters, and nuclear power plants.
Structure of Lustre programs
[edit]A Lustre program is a series of node definitions, written as:
node foo(a : bool) returns (b : bool);
let
b = not a;
tel
Where foo is the name of the node, a is the name of the single input of this node and b is the name of the single output.
In this example the node foo returns the negation of its input a, which is the expected result.
Inner variables
[edit]Additional internal variables can be declared as follows:
node Nand(X,Y: bool) returns (Z: bool);
var U: bool;
let
U = X and Y;
Z = not U;
tel
Note: The equations order doesn't matter, the order of lines U = X and Y; and Z = not U; doesn't change the result.
Special operators
[edit]pre p |
Returns the value of p in the previous cycle |
p -> q |
Set p as the initial value of the expression q |
Examples
[edit]Rising Edge detection
[edit]node RisingEdge (X : bool) returns (E : bool);
let
E = X and not pre X;
tel
Falling Edge detection
[edit]node FallingEdge (X : bool) returns (E : bool);
let
E = not X and pre X;
tel
See also
[edit]References
[edit]- ^ [1] N. Halbwachs et al. The Synchronous Data Flow Programming Language LUSTRE. In Proc. IEEE 1991 Vol. 79, No. 9. Accessed 17 March 2014.
- ^ "SCADE Success Stories". Archived from the original on 30 January 2019. Retrieved 8 June 2013.
External links
[edit]- Synchrone Lab Archived 2020-11-25 at the Wayback Machine Official website
- SCADE product page