Mercurial > repos > other > SevenLanguagesInSevenWeeks
comparison 6-Clojure/banking.clj @ 85:67e2bb3bcccd
Add bank account processing with refs and dosync calls
Also included a "transfer" function to atomically transfer money.
| author | IBBoard <dev@ibboard.co.uk> |
|---|---|
| date | Sun, 09 Jun 2019 19:47:01 +0100 |
| parents | |
| children |
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| 84:920b50be0fe5 | 85:67e2bb3bcccd |
|---|---|
| 1 (def accounts (ref [])) | |
| 2 | |
| 3 (defn add_account [accts] | |
| 4 (dosync (alter accts conj 0))) | |
| 5 | |
| 6 (defn credit [accts acct_num amount] | |
| 7 (dosync | |
| 8 (alter accts assoc acct_num (+ (accts acct_num) amount)) | |
| 9 ) | |
| 10 ) | |
| 11 | |
| 12 (defn debit [accts acct_num amount] | |
| 13 (dosync | |
| 14 (alter accts assoc acct_num (- (accts acct_num) amount)) | |
| 15 ) | |
| 16 ) | |
| 17 | |
| 18 (defn transfer [accts acct_from acct_to amount] | |
| 19 (dosync | |
| 20 (debit accts acct_from amount) | |
| 21 (credit accts acct_to amount) | |
| 22 ) | |
| 23 ) | |
| 24 | |
| 25 (add_account accounts) | |
| 26 (add_account accounts) | |
| 27 (add_account accounts) | |
| 28 (credit accounts 0 100) | |
| 29 (credit accounts 1 50) | |
| 30 (credit accounts 2 500) | |
| 31 (transfer accounts 2 1 150) | |
| 32 (println @accounts) ; We should get [100, 200, 350] |