Fixed bug that will cause formulas such as 1*-2^2 failed

NielXu · Dec 5, 2018 · 14e4f52 · 14e4f52
1 parent 173c5dd
commit 14e4f52
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Showing 2 changed files with 15 additions and 7 deletions.
diff --git a/ast.py b/ast.py
@@ -55,10 +55,18 @@ def add(self, sym):
                     self.cur.left = node(sym, self.cur)
                     self.cur = self.cur.left
                 else:
-                    while self.cur.left is not None or expr.is_unary(self.cur.sym):
+                    temp = self.cur
+                    while self.cur is not None and (self.cur.left is not None or expr.is_unary(self.cur.sym)):
                         self.cur = self.cur.parent
-                    self.cur.left = node(sym, self.cur)
-                    self.cur = self.cur.left
+                    if self.cur is None:
+                        n = node(sym)
+                        n.right = self.root
+                        self.root.parent = n
+                        self.root = n
+                        self.cur = temp
+                    else:
+                        self.cur.left = node(sym, self.cur)
+                        self.cur = self.cur.left
             else:
                 if self.cur.right is None:
                     self.cur.right = node(sym, self.cur)
@@ -303,9 +311,9 @@ def main():
 
 
 def test():
-    a = build("-1^2")
+    a = build("-1*--2^-2")
     view(a)
-    print(evaluate(a.root))
+    print(evaluate(a))
 
 
 if __name__ == "__main__":

diff --git a/expr.py b/expr.py
@@ -39,7 +39,7 @@
     "-": lambda x,y : x-y,
     "*": lambda x,y : x*y,
     "/": lambda x,y : x/y,
-    "^": lambda x,y : x**y,
+    "^": lambda x,y : x**y
 }
 symbols.update(opeartors_mapper)
 
@@ -414,4 +414,4 @@ def _match_regex(r, e):
     for m in reg.finditer(e):
         starts.append(m.start())
         ends.append(m.end())
-    return starts, ends
+    return starts, ends