now pretty print works for scaler variables too.

theano/scalar/basic.py

@@ -22,7 +22,7 @@ import numpy
 
 import theano
 from theano.compat import PY3
-from theano import gof
+from theano import gof, printing
 from theano.gof import (Op, utils, Variable, Constant, Type, Apply,
                         FunctionGraph)
 from theano.gof.python25 import partial, all, any
@@ -31,6 +31,8 @@ from theano.configparser import config
 from theano.gradient import DisconnectedType
 from theano.gradient import grad_undefined
 
+from theano.printing import pprint
+
 builtin_complex = complex
 builtin_int = int
 builtin_float = float
@@ -2166,6 +2168,13 @@ class Neg(UnaryScalarOp):
         return "%(z)s = -%(x)s;" % locals()
 neg = Neg(same_out, name='neg')
 
+pprint.assign(add, printing.OperatorPrinter('+', -2, 'either'))
+pprint.assign(mul, printing.OperatorPrinter('*', -1, 'either'))
+pprint.assign(sub, printing.OperatorPrinter('-', -2, 'left'))
+pprint.assign(neg, printing.OperatorPrinter('-', 0, 'either'))
+pprint.assign(true_div, printing.OperatorPrinter('/', -1, 'left'))
+pprint.assign(int_div, printing.OperatorPrinter('//', -1, 'left'))
+pprint.assign(pow, printing.OperatorPrinter('**', 1, 'right'))
 
 class Inv(UnaryScalarOp):
     """ multiplicative inverse. Also called reciprocal"""
@@ -3099,7 +3108,7 @@ class Composite(ScalarOp):
                 for i, r in enumerate(self.fgraph.variables):
                     if r not in io and len(r.clients) > 1:
                         r.name = 't%i' % i
-                rval = "Composite{%s}" % str(self.fgraph)
+                rval = "Composite{%s}" % pprint(self.fgraph.outputs[0])
         self.name = rval
 
     def init_fgraph(self):