Discussion on: Functional Programming in Dart

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This looks compelling, but I am not sure it is. Dart isn't a functional programming language, and this package, though very compelling on the surface of it, seems to help, I am not sure I would want to use it in my projects. I understand that implementing things like Either and Option is hard, but the code below I would not want to ever write, and I am not sure I would like to have it in any library included in my application

  static Function1<Either<L, A>, Either<L, B>> lift<L, A, B>(B f(A a)) => ((Either<L, A> oa) => oa.map(f));
  static Function2<Either<L, A>, Either<L, B>, Either<L, C>> lift2<L, A, B, C>(C f(A a, B b)) => (Either<L, A> fa, Either<L, B> fb) => map2(fa, fb, f);
  ...
  static Function19<Either<L, A>, Either<L, B>, Either<L, C>, Either<L, D>, Either<L, E>, Either<L, F>, Either<L, G>, Either<L, H>, Either<L, I>, Either<L, J>, Either<L, K>, Either<L, LL>, Either<L, M>, Either<L, N>, Either<L, O>, Either<L, P>, Either<L, Q>, Either<L, R>, Either<L, S>, Either<L, T>> lift19<L, A, B, C, D, E, F, G, H, I, J, K, LL, M, N, O, P, Q, R, S, T>(T f(A a, B b, C c, D d, E e, F f, G g, H h, I i, J j, K k, LL l, M m, N n, O o, P p, Q q, R r, S s)) => (Either<L, A> fa, Either<L, B> fb, Either<L, C> fc, Either<L, D> fd, Either<L, E> fe, Either<L, F> ff, Either<L, G> fg, Either<L, H> fh, Either<L, I> fi, Either<L, J> fj, Either<L, K> fk, Either<L, LL> fl, Either<L, M> fm, Either<L, N> fn, Either<L, O> fo, Either<L, P> fp, Either<L, Q> fq, Either<L, R> fr, Either<L, S> fs) => map19(fa, fb, fc, fd, fe, ff, fg, fh, fi, fj, fk, fl, fm, fn, fo, fp, fq, fr, fs, f);
  static Function20<Either<L, A>, Either<L, B>, Either<L, C>, Either<L, D>, Either<L, E>, Either<L, F>, Either<L, G>, Either<L, H>, Either<L, I>, Either<L, J>, Either<L, K>, Either<L, LL>, Either<L, M>, Either<L, N>, Either<L, O>, Either<L, P>, Either<L, Q>, Either<L, R>, Either<L, S>, Either<L, T>, Either<L, U>> lift20<L, A, B, C, D, E, F, G, H, I, J, K, LL, M, N, O, P, Q, R, S, T, U>(U f(A a, B b, C c, D d, E e, F f, G g, H h, I i, J j, K k, LL l, M m, N n, O o, P p, Q q, R r, S s, T t)) => (Either<L, A> fa, Either<L, B> fb, Either<L, C> fc, Either<L, D> fd, Either<L, E> fe, Either<L, F> ff, Either<L, G> fg, Either<L, H> fh, Either<L, I> fi, Either<L, J> fj, Either<L, K> fk, Either<L, LL> fl, Either<L, M> fm, Either<L, N> fn, Either<L, O> fo, Either<L, P> fp, Either<L, Q> fq, Either<L, R> fr, Either<L, S> fs, Either<L, T> ft) => map20(fa, fb, fc, fd, fe, ff, fg, fh, fi, fj, fk, fl, fm, fn, fo, fp, fq, fr, fs, ft, f);

A significant effort for sure, but again, nah...

Marcos Sevilla • Sep 21 '21

Yeah, I highly suggest checking out the package oxidized as dartz hasn't been updated in a while. The post originally was to explain how to bring functional approaches to Dart, but its use is optional, having functions as first-class citizens is the only functional characteristic by default.