olexale
/ maybe_dart.dart
Created
January 3, 2022 19:10
Sample for the "Dart Functors, Applicatives, And Monads In Pictures" article
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| void main() { | |
| // Functor | |
| num plus3(num x) => x + 3; | |
| print(Just(2).fmap(plus3)); // Just 5 | |
| print(Nothing<num>().fmap(plus3)); | |
| print([1,2,3].map((x) => x + 2)); // (3, 4, 5) | |
| final foo = fmap((x) => x + 3, (x) => x + 2); |
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| Future<void> main() async { | |
| // final program = '(define x 42)'; | |
| final program = '(begin (define circle-area (lambda (r) (* pi (* r r)))) (circle-area 10))'; | |
| print(parse(program)); | |
| } | |
| dynamic parse(String program) => parseTokens(tokenize(program)); | |
| List<String> tokenize(String program) => program | |
| .replaceAll('(', ' ( ') |
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| import 'dart:math' as math; | |
| Future<void> main() async { | |
| final program = '(begin (define circle-area (lambda (r) (* pi (* r r)))) (circle-area 10))'; | |
| print(eval(parse(program), standardEnv)); | |
| } | |
| dynamic parse(String program) => parseTokens(tokenize(program)); | |
| List<String> tokenize(String program) => program |
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