jneira

(defprotocol TradeTax
  (trade-tax [trade logic]))

(defprotocol Commission
  (commission [trade logic]))

(defrecord Trade [ref-no account instrument principal tax-fees
                  unit-price quantity])

(defn calculate-tax [{:keys [principal]} logic]

drj42

Org-mode Org-mode Reference Card

Org mode reference card

Created from the plain text reference card on orgmode.org Download this file, and open it in Emacs org-mode!

kristianhellquist

(defun copy-current-line-position-to-clipboard ()
  "Copy current line in file to clipboard as '</path/to/file>:<line-number>'"
  (interactive)
  (let ((path-with-line-number
         (concat (buffer-file-name) ":" (number-to-string (line-number-at-pos)))))
    (x-select-text path-with-line-number)
    (message (concat path-with-line-number " copied to clipboard"))))

(define-key global-map (kbd "M-l") 'copy-current-line-position-to-clipboard)

a2ndrade

;; see http://stackoverflow.com/questions/17190334/getting-the-id-of-an-inserted-entity-in-diatomic
(require '[datomic.api :as d])
(def uri "datomic:mem://test")
(d/create-database uri)
(def conn (d/connect uri))

;; create an atribute
(d/transact conn [{:db/id #db/id[:db.part/db]
                   :db/ident :some/attribute
                   :db/valueType :db.type/string

zsup

Documentation-Driven Development

The philosophy behind Documentation-Driven Development is a simple: from the perspective of a user, if a feature is not documented, then it doesn't exist, and if a feature is documented incorrectly, then it's broken.

• Document the feature first. Figure out how you're going to describe the feature to users; if it's not documented, it doesn't exist. Documentation is the best way to define a feature in a user's eyes.
• Whenever possible, documentation should be reviewed by users (community or Spark Elite) before any development begins.
• Once documentation has been written, development should commence, and test-driven development is preferred.
• Unit tests should be written that test the features as described by the documentation. If the functionality ever comes out of alignment with the documentation, tests should fail.
• When a feature is being modified, it should be modified documentation-first.
• When documentation is modified, so should be the tests.

john2x

Clojure Destructuring Tutorial and Cheat Sheet

(Related blog post)

Simply put, destructuring in Clojure is a way extract values from a datastructure and bind them to symbols, without having to explicitly traverse the datstructure. It allows for elegant and concise Clojure code.

Vectors and Sequences

wincent

2015-01-29 Unofficial Relay FAQ

Compilation of questions and answers about Relay from React.js Conf.

Disclaimer: I work on Relay at Facebook. Relay is a complex system on which we're iterating aggressively. I'll do my best here to provide accurate, useful answers, but the details are subject to change. I may also be wrong. Feedback and additional questions are welcome.

What is Relay?

Relay is a new framework from Facebook that provides data-fetching functionality for React applications. It was announced at React.js Conf (January 2015).

statonjr

We're working on a project that uses the Datomic Pull API to pull specific attributes out of Datomic entities. Here's an example of query that uses the Pull API:

(d/q '[:find [(pull ?e [:sales/deal_number :sales/deal_close_date :sales/state]) ...] 
       :in $ ?date 
       :where [?e :sales/deal_close_date ?d _ _] [(> ?d ?date)]] 
       db 
       (days-ago-at-midnight 1))

oliyh

(defmacro condas->
  "A mixture of cond-> and as-> allowing more flexibility in the test and step forms"
  [expr name & clauses]
  (assert (even? (count clauses)))
  (let [pstep (fn [[test step]] `(if ~test ~step ~name))]
    `(let [~name ~expr
           ~@(interleave (repeat name) (map pstep (partition 2 clauses)))]
       ~name)))

mjason

;; please install web-mode
;; in your .emacs.d/init.el
(add-to-list 'auto-mode-alist '(".*/react/.*\\.js[x]?\\'" . web-mode))
(setq web-mode-content-types-alist
  '(("jsx"  . "/.*/react/.*\\.js[x]?\\'")))