got initial lexer almost working

src/hs_robotwar/core.clj

@@ -1,58 +1,140 @@
 (ns hs-robotwar.core)
 
+(defn add-column-metadata
+  [s n]
+  {:string s, 
+   :column n})
 
+(def registers (set (concat (map #(-> % char str) (range 65 91))
+                            ["AIM" "SHOT" "RADAR" "DAMAGE" "SPEEDX" "SPEEDY" "RANDOM" "INDEX"])))
 
-(def error-type-map
-  {:parse-error "Parse Error"
-   :end-of-line-error "End of Line Error"})
+(def operators #{\= \< \> \# \+ \- \* \/})
 
-(defn error 
-  [error-type error-string]
-  (str (error-type-map error-type) ": " error-string))
+(defn int-str?
+  [string]
+  (re-find #"^-?\d+$" string))
 
-(defn valid-number-string
-  [n]
-  (re-find #"^-?\d+\.?\d*$" n))
-
-(defn number-or-string
-  [x]
-  (if (valid-number-string x)
-    (Float/parseFloat x)
-    x))
+(defn lex
+  [initial-line]
+  (loop
+    [line initial-line
+     partial-token ""
+     pos 0
+     result []]
+    (let [conj-to-result (fn [s] (conj result (add-column-metadata s pos)))
+          new-pos (fn [] (- (count initial-line) (count line)))
+          previous-token (last result)
+          parsing-token? (not (empty? partial-token))
+          first-char (first line)
+          rest-of-line (rest line)]
+      (cond
+        (or (empty? line) (= \; first-char)) (if parsing-token?
+                                                 (conj-to-result partial-token)
+                                                 result)
+        (#{\space \tab} first-char) (if parsing-token?
+                                        (recur rest-of-line "" pos (conj-to-result partial-token))
+                                        (recur rest-of-line "" pos result))
+        (= \- first-char) (when (and (int-str? (str (second line)))
+                                      (not (or (int-str? previous-token)
+                                               (registers previous-token))))
+                               ; if true => the minus sign is the beginning of a number
+                               (recur rest-of-line (str first-char) (new-pos) result))
+        (operators first-char) (recur rest-of-line "" (new-pos) (conj-to-result (str first-char)))
+        :else (recur rest-of-line (str partial-token first-char) pos result)))))
   
-(defn parse
-  "parses a line, by returning a map with the expression, and meta-
-  information. Right now the value is just a number if it's supposed
-  to be a number, otherwise the original string."
-  [line]
-  (reduce (fn [ast ]))
-  (map (fn [word]
-         {:column-number }
-         (number-or-string word))
-       (re-seq #"\S+" line)))
+  
+; (def prettyprint-tokens [token-seq]
+;   (map #(println (:column %) (:string %))))  
+; [{:string "IF", :column 0} 
+;  {:string "DAMAGE", :column 0} 
+;  {:string "#", :column 0} 
+;  {:string "D", :column 10} 
+;  {:string "GOTO", :column 10} 
+;  {:string "MOVE", :column 10}]
 
-(defn validate-expr
-  "right now just checks to see whether it's a number.
-   will do a lot more things in the future."
-  [expr]
-  (if (number? expr)
-    [expr nil]
-    [expr (error :parse-error "Not a number")]))
+        
+        
+        
+        
+           
+           
   
 
-(defn evaluate
-  "evaluates an ast (right now just prints it).
-  Checks to see if it's a string because that's
-  the way errors are passed. We'll change that."
-  [ast]
-  (if (string? ast)
-    ast
-    (apply str (interpose " " ast))))
+
+; (def error-type-map
+;   {:parse-error "Parse Error"
+;    :end-of-line-error "End of Line Error"})
+
+; (defn error 
+;   [error-type error-string]
+;   (str (error-type-map error-type) ": " error-string))
+
+; (defn valid-number-string
+;   [n]
+;   (re-find #"^-?\d+\.?\d*$" n))
+
+; (defn number-or-string
+;   [x]
+;   (if (valid-number-string x)
+;     (Float/parseFloat x)
+;     x))
+
+; (defn string-with-idx
+;   [s, idx]
+;   (if (empty? s)
+;     nil
+;     {:string s
+;      :idx idx}))
+
+; (defn tokens-with-column-numbers
+;   "splits a string and returns a sequence of hashmaps,
+;   with column-number metadata. separated just by spaces
+;   for now. In the future, tokens won't necessarily have
+;   spaces between them."
+;   [s]
+;   (let [len (count s)]
+;     (loop [s s
+;            idx 0
+;            partial-word ""
+;            result []]
+;       (let [first-s (subs s 0 1)
+;             rest-s (subs s 1)]
+;         (cond
+;           (empty? s) (if (empty? partial-word)
+;                        result
+;                        (conj result (str-with-idx partial-word idx))
+;           (re-find #"\s" first-s) (if (empty? partial-word) 
+;                                     (recur rest-s idx "" result)
+;                                     (recur rest-s idx "" (conj result (str-with-idx
+;                                                                         partial-word idx))))
+;           :else (if (empty? partial-word)
+;                   (recur rest-s (- len (count s)) first-s result)
+;                   (recur rest-s idx (str partial-word first-s) result))))))))
+          
+
+
+; (defn validate-expr
+;   "right now just checks to see whether it's a number.
+;    will do a lot more things in the future."
+;   [expr]
+;   (if (number? expr)
+;     [expr nil]
+;     [expr (error :parse-error "Not a number")]))
   
 
-(defn repl
-  "make it so"
-  []
-  (loop []
-    (println (evaluate (parse (lex (read-line)))))
-    (recur)))
+; (defn evaluate
+;   "evaluates an ast (right now just prints it).
+;   Checks to see if it's a string because that's
+;   the way errors are passed. We'll change that."
+;   [ast]
+;   (if (string? ast)
+;     ast
+;     (apply str (interpose " " ast))))
+  
+
+; (defn repl
+;   "make it so"
+;   []
+;   (loop []
+;     (println (evaluate (parse (lex (read-line)))))
+;     (recur)))