Add subtraction and division

src/bean/errors.cljs

@@ -41,6 +41,10 @@
   {:error "Matrices should be same size."
    :representation "Matrices should be same size."})
 
+(defn divide-by-zero []
+  {:error "can't divide by zero"
+   :representation "can't divide by zero"})
+
 (defn type-mismatch-+-op []
   {:error "+ only works for Integers"
    :representation "+ only works for Integers"})

src/bean/interpreter.cljs

@@ -118,11 +118,13 @@
                                 (eval-sub-ast right)))
                     (eval-sub-ast arg))
       :Value (eval-sub-ast arg)
-      :Integer (ast-result (js/parseInt arg))
+      :Number (ast-result (js/Number.parseFloat arg))
       :String (ast-result arg)
       :QuotedString (ast-result arg)
       :Operation (ast-result (case arg
                                "+" operators/bean-op-+
+                               "-" operators/bean-op-minus
+                               "/" operators/bean-op-div
                                "*" operators/bean-op-*
                                "<" operators/bean-op-<
                                ">" operators/bean-op->

src/bean/operators.cljs

@@ -1,30 +1,47 @@
 (ns bean.operators
   (:require [bean.errors :as errors]))
 
+;; This is a hack to work around JS's float weirdnesses.
+(defn format-number
+  [num]
+  (if (.isInteger js/Number num) num (js/Number (.toFixed num 4))))
+
 (defn bean-op-+ [left right]
-  (if (and (int? left) (int? right))
+  (if (and (number? left) (number? right))
     (+ left right)
     (errors/type-mismatch-+-op)))
 
+(defn bean-op-minus [left right]
+  (if (and (number? left) (number? right))
+    (format-number (- left right))
+    (errors/type-mismatch-+-op)))
+
+(defn bean-op-div [left right]
+  (if (and (number? left) (number? right))
+    (if (zero? right)
+      (errors/divide-by-zero)
+      (format-number (/ left right)))
+    (errors/type-mismatch-+-op)))
+
 (defn bean-op-< [left right]
-  (if (and (int? left) (int? right))
+  (if (and (number? left) (number? right))
     (< left right)
     (errors/type-mismatch-<-op)))
 
 (defn bean-op-> [left right]
-  (if (and (int? left) (int? right))
+  (if (and (number? left) (number? right))
     (> left right)
     (errors/type-mismatch->-op)))
 
 (defn bean-op-= [left right]
   (if (and (or (string? left)
-               (int? left))
+               (number? left))
            (or (string? right)
-               (int? right)))
+               (number? right)))
     (= left right)
     (errors/type-mismatch-=-op)))
 
 (defn bean-op-* [left right]
-  (if (and (int? left) (int? right))
+  (if (and (number? left) (number? right))
     (* left right)
     (errors/type-mismatch-*-op)))

src/bean/parser/parser.cljs

@@ -12,14 +12,14 @@
   ;; TODO: Integers are currently just natural numbers
   "
     CellContents = <'='> Expression / RawValue / Epsilon
-    <RawValue> =  Integer / String
-    Integer = #'[0-9]+'
+    <RawValue> =  Number / String
+    Number = #'[-]?[0-9]+([.][0-9]+)?'
     String = #'.*'
 
     CellRef = #'[A-Z]+' #'[1-9][0-9]*'
     MatrixRef = CellRef <':'> CellRef
 
-    Operation = '+' | '*' | '=' | '<' | '>'
+    Operation = '+' | '*' | '=' | '<' | '>' | '/' | '-'
     Expression = (Value | CellRef | MatrixRef | FunctionChain |
                 Expression Operation Expression | FunctionInvocation |
                 FunctionDefinition | FrameLookup) / Name
@@ -32,7 +32,7 @@
     FrameLookup = <'$'> Name
     LabelLookup = Name
 
-    Value = Integer / <'\"'> QuotedString <'\"'>
+    Value = Number / <'\"'> QuotedString <'\"'>
     QuotedString = #'[^\"]+'
     ")