Update stringpict.py

sympy/printing/pretty/stringpict.py

@@ -203,7 +203,7 @@ def parens(self, left='(', right=')', ifascii_nougly=False):
             rparen = stringPict(vobj(right, h), baseline=b)
             res = stringPict(*res.right(rparen))
 
-        return ('\n'.join(res.picture), res.baseline)
+        return self.__class__('\n'.join(res.picture), res.baseline)
 
     def leftslash(self):
         """Precede object by a slash of the proper size.
@@ -431,12 +431,12 @@ def __add__(self, *others):
         """
         arg = self
         if arg.binding > prettyForm.NEG:
-            arg = stringPict(*arg.parens())
+            arg = arg.parens()
         result = [arg]
         for arg in others:
             #add parentheses for weak binders
             if arg.binding > prettyForm.NEG:
-                arg = stringPict(*arg.parens())
+                arg = arg.parens()
             #use existing minus sign if available
             if arg.binding != prettyForm.NEG:
                 result.append(' + ')
@@ -450,9 +450,9 @@ def __truediv__(self, den, slashed=False):
             raise NotImplementedError("Can't do slashed fraction yet")
         num = self
         if num.binding == prettyForm.DIV:
-            num = stringPict(*num.parens())
+            num = num.parens()
         if den.binding == prettyForm.DIV:
-            den = stringPict(*den.parens())
+            den = den.parens()
 
         if num.binding==prettyForm.NEG:
             num = num.right(" ")[0]
@@ -476,14 +476,14 @@ def __mul__(self, *others):
         # add parens on args that need them
         arg = self
         if arg.binding > prettyForm.MUL and arg.binding != prettyForm.NEG:
-            arg = stringPict(*arg.parens())
+            arg = arg.parens()
         result = [arg]
         for arg in others:
             if arg.picture[0] not in quantity.values():
                 result.append(xsym('*'))
             #add parentheses for weak binders
             if arg.binding > prettyForm.MUL and arg.binding != prettyForm.NEG:
-                arg = stringPict(*arg.parens())
+                arg = arg.parens()
             result.append(arg)
 
         len_res = len(result)
@@ -517,29 +517,31 @@ def __pow__(self, b):
         a = self
         use_inline_func_form = False
         if b.binding == prettyForm.POW:
-            b = stringPict(*b.parens())
+            b = b.parens()
         if a.binding > prettyForm.FUNC:
-            a = stringPict(*a.parens())
+            a = a.parens()
         elif a.binding == prettyForm.FUNC:
             # heuristic for when to use inline power
             if b.height() > 1:
-                a = stringPict(*a.parens())
+                a = a.parens()
             else:
                 use_inline_func_form = True
 
         if use_inline_func_form:
             #         2
             #  sin  +   + (x)
             b.baseline = a.prettyFunc.baseline + b.height()
-            func = stringPict(*a.prettyFunc.right(b))
-            return prettyForm(*func.right(a.prettyArgs))
+            func = prettyForm(*a.prettyFunc.right(b))
+            return func.right(a.prettyArgs)
         else:
             #      2    <-- top
             # (x+y)     <-- bot
-            top = stringPict(*b.left(' '*a.width()))
-            bot = stringPict(*a.right(' '*b.width()))
+            top = b.left(' '*a.width())
+            bot = a.right(' '*b.width())
 
-        return prettyForm(binding=prettyForm.POW, *bot.above(top))
+        result = bot.above(top)
+        result.binding = prettyForm.POW
+        return result
 
     simpleFunctions = ["sin", "cos", "tan"]
 
@@ -554,11 +556,19 @@ def apply(function, *args):
             arg = args[0].__pretty__()
             if arg.binding <= prettyForm.DIV:
                 #optimization: no parentheses necessary
-                return prettyForm(binding=prettyForm.FUNC, *arg.left(function + ' '))
+                result = arg.left(function + ' ')
+                result.binding = prettyForm.FUNC
+                return result
         argumentList = []
         for arg in args:
             argumentList.append(',')
             argumentList.append(arg.__pretty__())
-        argumentList = stringPict(*stringPict.next(*argumentList[1:]))
-        argumentList = stringPict(*argumentList.parens())
-        return prettyForm(binding=prettyForm.ATOM, *argumentList.left(function))
+        if argumentList:
+            first_arg, *rest = argumentList
+            argument_pict = first_arg.right(*rest)
+        else:
+            argument_pict = stringPict("")
+        argument_pict = argumentList.parens()
+        func_pict = argumentList.left(function)
+        func_pict.binding = prettyForm.ATOM
+        return func_pict