Merge pull request #17 from ryukinix/valid-operators

Add valid operators to webapp and add aliases

Author: ryukinix

src/operators.lisp

@@ -7,7 +7,7 @@
 (eval-when (:compile-toplevel)
   (defconstant F nil))
 
-(defparameter *valid-operators* '(~ ^ <=> => v [+]))
+(defparameter *valid-operators* '(~ ^ <=> => -> <-> v [+]))
 
 ;; operators
 (defun ~ (p)
@@ -23,13 +23,21 @@
   (or p q))
 
 (defun => (p q)
-  "Implication binary operator"
+  "Conditional binary operator"
   (v (~ p) q))
 
 (defun <=> (p q)
   "Biconditional binary operator"
   (^ (=> p q) (=> q p)))
 
+(defun -> (p q)
+  "Notation alias for conditional"
+  (=> p q))
+
+(defun <-> (p q)
+  "Notation alias for biconditional"
+  (<=> p q))
+
 (defun [+] (p q)
   "XOR operator or exclusive disjunction operator"
   (^ (~ (^ p q))

src/package.lisp

@@ -47,5 +47,6 @@
            #:truth
            #:truth-infix
            #:*output-stream*
+           #:*valid-operators*
            #:main)
   (:nicknames "INFERENCE"))

web/webapp.lisp

@@ -78,7 +78,15 @@
               :placeholder (trim-paren (prop table)))
       (:input :type "submit"
               :value "Eval"))
-    (:pre (truth table))))
+    (:pre (truth table))
+    (:pre (format nil "Operators: ~a" inference:*valid-operators*))
+    (:p "Some notes: "
+        (:ul
+         (loop for note in '("My lexer doesn't works very well for parenthesis."
+                             "Please, don't be evil. Use less than 10 variables."
+                             "Yes, [+] it's a XOR. Mathematically: p ⊕ q."
+                             "(=> ->) and (<=> <->) are aliases.")
+               do (:li (render note)))))))
 
 (defmethod render ((string string))
   (with-html