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very close to getting lexer working

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Richard Harrington 2013-07-04 02:47:06 -04:00
parent 2c57527919
commit d9f03a10fe
1 changed files with 17 additions and 9 deletions
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26
src/hs_robotwar/core.clj
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@ -5,9 +5,13 @@
(def operators #{"=" "<" ">" "#" "+" "-" "*" "/"})
(defn digit?
[string-or-char]
(re-find #"\d" (str string-or-char)))
(defn int-str?
[string]
(re-find #"^-?\d+$" string))
(re-find #"^-?\d+$" (str string)))
(defn lex
[initial-line]
@ -20,11 +24,11 @@
(conj coll {:string s, :column n}))
close-partial-token (fn [] (conj-with-metadata result partial-token saved-pos))
current-pos (- (count initial-line) (count line))
previous-token (last result)
previous-token (:string (last result) "")
parsing-token? (not (empty? partial-token))
head (str (first line))
tail (rest line)]
(println head (class head))
(println head current-pos parsing-token? previous-token)
(cond
(or (empty? line) (= ";" head)) (if parsing-token?
(close-partial-token)
@ -32,14 +36,16 @@
(#{" " "\t"} head) (if parsing-token?
(recur tail "" saved-pos (close-partial-token))
(recur tail "" saved-pos result))
(= "-" head) (when (and (int-str? (str (second line)))
(not (or (int-str? (previous-token :string))
(registers previous-token))))
; when true => the minus sign is the beginning of a number
(recur tail head current-pos result))
(operators head) (if parsing-token?
; go back to the same point, but with the partial token closed
(recur line "" saved-pos (close-partial-token))
(recur tail "" current-pos (conj-with-metadata result head current-pos)))
; make sure we're not a unary minus sign operator
; by making sure that if we are a minus sign,
; the previous token is, or could represent, a number.
(when (or (not= "-" head)
(digit? (last previous-token))
(registers previous-token))
(recur tail "" current-pos (conj-with-metadata result head current-pos))))
:else (recur tail (str partial-token head) saved-pos result)))))
@ -52,6 +58,8 @@
(defn ppt [token-seq]
(println (pretty-print-tokens token-seq)))
(def p (comp ppt lex))