Parsing English

english-values.clj

;;; Author: Abhishek Mishra <ideamonk@gmail.com>

; ; http://www.reddit.com/r/dailyprogrammer/comments/zfeb2/9062012_challenge_96_intermediate_parsing_english/

; ;    seven     hundred  and   fourty-four    million
; (->  7         (* 100)  (+    40     4)      (* 1000000) )

; ;   ten-million     and ninety-four
; (-> 10 (* 1000000)  (+  90     4)    )

; ;   One-Thousand and Thirty-Four
; (-> 1   (* 1000) (+   30    4) )

; ;    Two  -Billion      and        One-Hundred-Fourty-Five-Thousand
; (-> 2    (* 1000000000) (+     (-> 1   (* 100) (+ 40 5)    (* 1000) ) )  )

; (-> 2 (* 1000000000) (+ (-> 1 (* 100) (+ 40) (+ 5) (* 1000))))

; ;   eleven-thousand and eight-hundred
; (-> 11     (* 1000) (+  (-> 8 (* 100)) ) )


; ; three-thousand and twenty
; (-> 3 (* 1000) (+ (-> 20)))


; assuming multipliers have locality indicated with '-'
; e.g. hundred and twenty-thousand  means: 100 and 20,000
;      hundred and twenty thousand means: (100 and 20) thousands

(def mapping {
  :zero       " (+  0) " 
  :one        " (+  1) " 
  :two        " (+  2) " 
  :three      " (+  3) " 
  :four       " (+  4) " 
  :five       " (+  5) " 
  :six        " (+  6) " 
  :seven      " (+  7) "
  :eight      " (+  8) " 
  :nine       " (+  9) " 
  :ten        " (+ 10) "
  :eleven     " (+ 11) " 
  :twelve     " (+ 12) "
  :thirteen   " (+ 13) "
  :fourteen   " (+ 14) "
  :fifteen    " (+ 15) "
  :sixteen    " (+ 16) "
  :seventeen  " (+ 17) "
  :eighteen   " (+ 18) "
  :nineteen   " (+ 19) "
  :twenty     " (+ 20) "
  :thirty     " (+ 30) "
  :forty      " (+ 40) "
  :fifty      " (+ 50) "
  :sixty      " (+ 60) "
  :seventy    " (+ 70) "
  :eighty     " (+ 80) "
  :ninety     " (+ 90) "
  ; multipliers - 

  :hundred      " (* 100) "
  :thousand     " (* 1000) "
  :million      " (* 1000000) "
  :billion      " (* 1000000000) "
  :trillion     " (* 1000000000000) "
  })

(defn parse [l]
  (let [f (first l)]
    (cond
      (= f "and") (concat ["(+ "] (parse [(first (rest l))]) [") "] (parse (rest (rest l))) )
      (not (empty? l)) (concat ["(-> "] (map str (map mapping (map keyword (re-seq #"\w+" f)))) (parse (rest l)) [")"])
      )))

(defn gimme-number [s]
  (load-string (apply str (parse (re-seq #"[a-z-]+" (.toLowerCase s))))))

(gimme-number "Two-Million and One-Hundred-Forty-Five Thousand")
; 2000145000

(gimme-number "Forty-Five-Hundred")
; 4500

(gimme-number "Forty-Five-Hundred and ninety-eight")
; 4598

(gimme-number "three-thousand and twenty")
; 3020

(gimme-number "One-Thousand and Thirty-Four")
; 1034

(gimme-number "Ten-Million     and Ninety-Four")
; 10000094

(gimme-number "Seven-Hundred and Forty-Four Million")
; 744000000

(gimme-number "Five-hundred and fifty-five million and four-hundred and forty thousand and twenty-five")
;555000440025