parser now handles the four basic '(+ - * /)

1 files changed, 27 insertions, 15 deletions

diff --git a/full-parse.rkt b/full-parse.rkt
index 25239a2..ae80640 100644
--- a/full-parse.rkt
+++ b/full-parse.rkt
@@ -4,31 +4,43 @@
 
 ; + - * / ^ ( ) [0-9]
 
+; 5+3*x
 (define (full-parse str)
   (define (get-general expr operator next-operation)
     (define (char->wanted c)
       ((if (char-numeric? c)
-        string->number string->symbol)
+         string->number string->symbol)
        (string c)))
+    ; used to add a completed part of the operation to the list of operations
+    ; 5 is one of those in the addition iteration
+    ; 3 and x are in the product iteration
     (define (add-operation-to-list operation seq)
+      ;(display (list operator "|" operation "|" seq))
+      ;(newline)
       (cons (if (= (length operation) 1) 
               (char->wanted (car operation))
               (next-operation operation))
             seq))
+    (define (contains value seq)
+      (memq value seq))
     (define (inner cfac facts rexpr)
       (cond
-        ((null? rexpr)
-         (reverse (add-operation-to-list cfac facts)))
-        ((eqv? (car rexpr) operator)
-         (inner '() (add-operation-to-list cfac facts) (cdr rexpr)))
-        (else
-          (inner (cons (car rexpr) cfac) facts (cdr rexpr)))))
-    (cons (char->wanted operator) (inner '() '() expr)))
+        [(null? rexpr)
+         (reverse (add-operation-to-list cfac facts))]
+        [(eqv? (car rexpr) operator)
+         (inner '() (add-operation-to-list cfac facts) (cdr rexpr))]
+        [else
+          (inner (cons (car rexpr) cfac) facts (cdr rexpr))]))
+    (if (not (contains operator expr))
+      (next-operation expr)
+      (cons (char->wanted operator) (inner '() '() expr))))
 
-  (define (get-parts expr)
-    (get-general 
-      expr 
-      #\+ 
-      (lambda (expr)
-        (get-general expr #\* (lambda (x) x)))))
-  (get-parts (string->list str)))
+  (define (create-trace expr ops)
+    (lambda (expr) 
+      (get-general expr (car ops) 
+                   (if (null? (cdr ops))
+                     (lambda (x) x)
+                     (create-trace expr (cdr ops))))))
+
+  (let ((expr (string->list str)))
+    ((create-trace expr '(#\+ #\- #\* #\/)) expr)))