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Diffstat (limited to 'emacs/.emacs.d/wpc/finance.el')
| -rw-r--r-- | emacs/.emacs.d/wpc/finance.el | 119 |
1 files changed, 0 insertions, 119 deletions
diff --git a/emacs/.emacs.d/wpc/finance.el b/emacs/.emacs.d/wpc/finance.el deleted file mode 100644 index b124061ccba3..000000000000 --- a/emacs/.emacs.d/wpc/finance.el +++ /dev/null @@ -1,119 +0,0 @@ -;;; finance.el --- Functions to help me organize my finances -*- lexical-binding: t -*- -;; Author: William Carroll <wpcarro@gmail.com> - -;;; Commentary: -;; Using functions to organize my financial thinking. - -;;; Code: - -;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; -;; Dependencies -;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; - -(require 'prelude) -(require 'math) - -;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; -;; Library -;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; - -(defvar finance/enable-tests? t - "When t, run the tests defined herein.") - -;; TODO: Support printing an org-table of these amount in a similar format to: -;; https://keisan.casio.com/exec/system/1234231998 -(cl-defun finance/future-value (amt - &key - num-years - (frequency 'monthly) - (interest-rate 0.06) - (payment-due-at 'beg) - (present-value 0)) - "Compute the Future Value of AMT. - -This function assumes that the interest rate is applied annually and not -monthly. - -This function will attempt to provide the following defaults: -- frequency: 'monthly -- interest-rate: 6% -- payment-due-at: 'beg -- present-value: 0.00" - (prelude/assert (set/contains? payment-due-at (set/new 'beg 'end))) - (prelude/assert (set/contains? frequency (set/new 'annually - 'semiannually - 'quarterly - 'monthly))) - (let ((pmt amt) - (k (alist/get frequency '((annually . 1) - (semiannually . 2) - (quarterly . 4) - (monthly . 12)))) - (r interest-rate) - (n num-years) - (pv present-value)) - (if (= 0 r) - (+ pv (* pmt n k)) - (if (equal 'beg payment-due-at) - (+ (* pv (math/exp (+ 1 (/ r k)) (* n k))) - (* pmt - (/ (- (math/exp (+ 1 (/ r k)) (* n k)) 1) - (/ r k)) - (+ 1 (/ r k)))) - (+ (* pv (math/exp (+ 1 (/ r k)) (* n k))) - (* pmt - (/ (- (math/exp (+ 1 (/ r k)) (* n k)) 1) - (/ r k)))))))) - -;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; -;; Tests -;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; - -(when finance/enable-tests? - (prelude/assert - (equal "1551.27" - (string/format "%0.2f" - (finance/future-value - 9.99 - :interest-rate 0.05 - :num-years 10 - :frequency 'monthly - :payment-due-at 'end - :present-value 0)))) - (prelude/assert - (equal "14318.34" - (string/format "%0.2f" - (finance/future-value 10.0 :num-years 35)))) - (prelude/assert - (equal "4200.00" - (string/format "%0.2f" - (finance/future-value - 10.0 - :interest-rate 0.0 - :num-years 35 - :frequency 'monthly - :payment-due-at 'beg - :present-value 0)))) - (prelude/assert - (equal "14318.34" - (string/format "%0.2f" - (finance/future-value - 10.0 - :interest-rate 0.06 - :num-years 35 - :frequency 'monthly - :payment-due-at 'beg - :present-value 0)))) - (prelude/assert - (equal "38282.77" - (string/format "%0.2f" - (finance/future-value - 10.0 - :interest-rate 0.1 - :num-years 35 - :frequency 'monthly - :payment-due-at 'beg - :present-value 0))))) - -(provide 'finance) -;;; finance.el ends here |