| const Task = require('data.task') | |
| Task.prototype.alt = function (that) { | |
| return new Task((rej, res) => | |
| this.fork(_ => that.fork(rej, res), res)) | |
| } | |
| const hosts = [ | |
| [ 'db1.mysite.com', 'user', 'password' ], | |
| [ 'db2.mysite.com', 'user', 'password' ], |
Let us make the array functor slightly uglier.
According to Functor's definition, for every type a,
we first need to define the type F(a),
the set of all admissible values for our Functor.
For the array Functor Array, that would be the set [a] of all arrays with entries of type a.
We now define a new Functor F, where we slightly change the set of values F(a):
Namely, we say that an array arr is of type F(a) if either
| var _ = require('lodash'); | |
| var log = require('../core/log.js'); | |
| var RSI = require('./indicators/RSI.js'); | |
| // let's create our own method | |
| var method = {}; | |
| // prepare everything our method needs | |
| method.init = function() { |
| ✗ ghcup install | |
| Installing GHC-8.6.5 for Darwin on architecture x86_64 | |
| usage: mktemp [-d] [-q] [-t prefix] [-u] template ... | |
| mktemp [-d] [-q] [-u] -t prefix | |
| Failed to create temporary directory |
| ✗ cabal v2-build | |
| Warning: The package list for 'hackage.haskell.org' does not exist. Run 'cabal | |
| update' to download it. | |
| Resolving dependencies... | |
| cabal: Could not resolve dependencies: | |
| [__0] next goal: ptghci (user goal) | |
| [__0] rejecting: ptghci-0.1.0.0 (conflict: pkg-config package python3-any, not | |
| found in the pkg-config database) | |
| [__0] fail (backjumping, conflict set: ptghci) | |
| After searching the rest of the dependency tree exhaustively, these were the |
| Trying to install | |
| https://github.com/litxio/ptghci | |
| ✗ cabal v2-build | |
| Build profile: -w ghc-8.0.1 -O1 | |
| In order, the following will be built (use -v for more details): | |
| - ptghci-0.1.0.0 (lib) (first run) | |
| - ptghci-0.1.0.0 (exe:ptghci) (first run) | |
| Preprocessing library for ptghci-0.1.0.0.. | |
| Building library for ptghci-0.1.0.0.. |
| λ [9]: fmap f [1] | |
| Out [9]: | |
| <interactive>:186:1: error: | |
| • Ambiguous type variable ‘f0’ arising from a use of ‘print’ | |
| prevents the constraint ‘(Show (f0 Integer))’ from being solved. | |
| Probable fix: use a type annotation to specify what ‘f0’ should be. | |
| These potential instances exist: | |
| instance Show a => Show (ZipList a) | |
| -- Defined in ‘Control.Applicative’ |
| With no local config present, `stack` is picking the old ghc 8.2.2: | |
| ```sh | |
| ➜ test stack ghci | |
| Note: No local targets specified, so a plain ghci will be started with no package hiding or package options. | |
| You are using snapshot: lts-11.9 | |
| If you want to use package hiding and options, then you can try one of the following: |
| ```sh | |
| ➜ ~ stack install sized | |
| Error: While constructing the build plan, the following exceptions were encountered: | |
| In the dependencies for sized-0.3.0.0: | |
| equational-reasoning must match >=0.5, but the stack configuration has no specified version (latest matching | |
| version is 0.6.0.0) | |
| ghc-typelits-presburger must match >=0.2.0.0, but the stack configuration has no specified version (latest | |
| matching version is 0.2.0.5) |