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One easy example of Reactive Programming.
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| #include <stdio.h> | |
| #include <stdlib.h> | |
| typedef struct ReactiveInt* ReactiveInt; | |
| struct ReactiveInt | |
| { | |
| int n; | |
| int (*operator)(int, int); | |
| ReactiveInt left, right; | |
| }; | |
| #define ReactiveNum(n) NewReactive((n), NULL, NULL, NULL) | |
| #define ReactiveAdd(l, r) NewReactive(0, Add, (l), (r)) | |
| #define ReactiveSub(l, r) NewReactive(0, Sub, (l), (r)) | |
| #define ReactiveMul(l, r) NewReactive(0, Mul, (l), (r)) | |
| #define ReactiveDiv(l, r) NewReactive(0, Div, (l), (r)) | |
| int Add(int a, int b) { return a + b; } | |
| int Sub(int a, int b) { return a - b; } | |
| int Mul(int a, int b) { return a * b; } | |
| int Div(int a, int b) { return a / b; } | |
| ReactiveInt NewReactive(int n, int (*operator)(int, int), ReactiveInt left, ReactiveInt right) | |
| { | |
| ReactiveInt ri = malloc(sizeof(struct ReactiveInt)); | |
| ri->n = n; | |
| ri->operator = operator; | |
| ri->left = left; | |
| ri->right = right; | |
| return ri; | |
| } | |
| int PullValue(ReactiveInt a) | |
| { | |
| if (a->operator == NULL) { | |
| return a->n; | |
| } else { | |
| return a->operator(PullValue(a->left), PullValue(a->right)); | |
| } | |
| } | |
| void SetReactiveNum(ReactiveInt a, int n) | |
| { | |
| a->n = n; | |
| } | |
| void main() | |
| { | |
| ReactiveInt a, b, c, d, e, f, g; | |
| a = ReactiveNum(1); // a = 1 | |
| b = ReactiveNum(2); // b = 2 | |
| c = ReactiveNum(3); // c = 3 | |
| d = ReactiveNum(4); // d = 4 | |
| e = ReactiveAdd(a, b); // e = a + b | |
| f = ReactiveSub(c, d); // f = c - d | |
| g = ReactiveMul(e, f); // g = e * f | |
| printf("%d\n", PullValue(g)); // print g | |
| SetReactiveNum(a, 100); // a = 100 | |
| printf("%d\n", PullValue(g)); // print g | |
| } |
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