python3 compatible parse_variables (#1428)

* note: in py3 pickles have to be read as binary files
* fancier py3 printing

docs/source/examples/beam.py

@@ -39,8 +39,8 @@ class Beam(Model):
     w_tip
 
     """
+    @parse_variables(__doc__, globals())
     def setup(self, N=4):
-        exec(parse_variables(self.__doc__))
         # minimize tip displacement (the last w)
         self.cost = self.w_tip = w[-1]
         return {

docs/source/examples/boundschecking.py

@@ -28,8 +28,8 @@ class BoundsChecking(Model):
     D
 
     """
+    @parse_variables(__doc__, globals())
     def setup(self):
-        exec(parse_variables(BoundsChecking.__doc__))
         self.cost = F
         return [
             F >= D + T,
@@ -50,9 +50,10 @@ def setup(self):
     pass
 gp = m.gp(allow_missingbounds=True)
 
-bplate = ", but would gain it from any of these sets of bounds: "
-assert {(m.D.key, 'lower'): bplate + "[(%s, 'lower')]" % m.Ap,
-        (m.Ap.key, 'lower'): bplate + ("[(%s, 'lower')]"
-                                       " or [(%s, 'lower')]" % (m.D, m.nu)),
-        (m.nu.key, 'lower'): bplate + "[(%s, 'lower')]" % m.Ap
-       } == gp.missingbounds
+bpl = ", but would gain it from any of these sets of bounds: "
+assert gp.missingbounds[(m.D.key, 'lower')] == bpl + "[(%s, 'lower')]" % m.Ap
+assert gp.missingbounds[(m.nu.key, 'lower')] == bpl + "[(%s, 'lower')]" % m.Ap
+# ordering is arbitrary:
+assert gp.missingbounds[(m.Ap.key, 'lower')] in (
+    bpl + ("[(%s, 'lower')] or [(%s, 'lower')]" % (m.D, m.nu)),
+    bpl + ("[(%s, 'lower')] or [(%s, 'lower')]" % (m.nu, m.D)))

docs/source/examples/docstringparsing.py

@@ -1,5 +1,6 @@
 "Docstring parsing example"
 from gpkit import Model, parse_variables
+from gpkit.tools.docstring import parse_varstring
 
 
 class Cube(Model):
@@ -33,15 +34,15 @@ class Cube(Model):
     The ordering of these blocks doesn't affect anything; order them in the
     way that makes the most sense to someone else reading your model.
     """
+    @parse_variables(__doc__, globals())
     def setup(self):
-        exec(parse_variables(Cube.__doc__))
 
         return [A >= 2*(s[0]*s[1] + s[1]*s[2] + s[2]*s[0]),
                 s.prod() >= V,
                 s[2] >= h]
 
 
-print(parse_variables(Cube.__doc__))
+print(parse_varstring(Cube.__doc__))
 c = Cube()
 c.cost = c.A
 print(c.solve(verbosity=0).table())

docs/source/examples/docstringparsing_output.txt

@@ -1,29 +1,33 @@
-from gpkit import Variable, VectorVariable
-
-try:
-    A = self.A = Variable('A', 'm^2', 'surface area')
-except Exception as e:
-    raise ValueError("`"+e.__class__.__name__+": "+str(e)+"` was raised"
-                     " while executing the parsed line `A = self.A = Variable('A', 'm^2', 'surface area')`. Is this line following the format `Name (optional Value) [Units] (Optional Description)` without any whitespace in the Name or Value fields?")
-
-try:
-    V = self.V = Variable('V', 100, 'L', 'minimum volume')
-except Exception as e:
-    raise ValueError("`"+e.__class__.__name__+": "+str(e)+"` was raised"
-                     " while executing the parsed line `V = self.V = Variable('V', 100, 'L', 'minimum volume')`. Is this line following the format `Name (optional Value) [Units] (Optional Description)` without any whitespace in the Name or Value fields?")
-
-try:
-    h = self.h = Variable('h', 1, 'm', 'minimum height')
-except Exception as e:
-    raise ValueError("`"+e.__class__.__name__+": "+str(e)+"` was raised"
-                     " while executing the parsed line `h = self.h = Variable('h', 1, 'm', 'minimum height')`. Is this line following the format `Name (optional Value) [Units] (Optional Description)` without any whitespace in the Name or Value fields?")
-
-try:
-    s = self.s = VectorVariable(3, 's', 'm', 'side length')
-except Exception as e:
-    raise ValueError("`"+e.__class__.__name__+": "+str(e)+"` was raised"
-                     " while executing the parsed line `s = self.s = VectorVariable(3, 's', 'm', 'side length')`. Is this line following the format `Name (optional Value) [Units] (Optional Description)` without any whitespace in the Name or Value fields?")
-
+from gpkit import Variable, VectorVariable  # Demonstration of nomenclature syntax
+# 
+#     Lines that end in "Variables" will be parsed as a scalar variable table
+#     until the next blank line.
+# 
+#     Variables
+#     ---------
+A = self.A = Variable('A', 'm^2', 'surface area')  # from 'A       [m^2]  surface area'
+V = self.V = Variable('V', 100, 'L', 'minimum volume')  # from 'V   100 [L]    minimum volume'
+# 
+#     Lines that end in "Variables of length $N" will be parsed as vector
+#     variables of length $N until the next blank line.
+# 
+#     Variables of length 3
+#     ---------------------
+s = self.s = VectorVariable(3, 's', 'm', 'side length')  # from 's       [m]    side length'
+# 
+#     Let's introduce more variables: (any line ending in "Variables" is parsed)
+# 
+#     Zoning Variables
+#     ----------------
+h = self.h = Variable('h', 1, 'm', 'minimum height')  # from 'h     1 [m]    minimum height'
+# 
+#     Upper Unbounded
+#     ---------------
+#     A
+# 
+#     The ordering of these blocks doesn't affect anything; order them in the
+#     way that makes the most sense to someone else reading your model.
+#     
 
 Cost
 ----

docs/source/examples/performance_modeling.py

@@ -21,10 +21,10 @@ class AircraftP(Model):
     Wfuel, aircraft.W, state.mu
 
     """
+    @parse_variables(__doc__, globals())
     def setup(self, aircraft, state):
         self.aircraft = aircraft
         self.state = state
-        exec(parse_variables(AircraftP.__doc__))
 
         self.wing_aero = aircraft.wing.dynamic(aircraft.wing, state)
         self.perf_models = [self.wing_aero]
@@ -62,8 +62,8 @@ class Aircraft(Model):
     ---------------
     wing.c, wing.S
     """
+    @parse_variables(__doc__, globals())
     def setup(self):
-        exec(parse_variables(Aircraft.__doc__))
         self.fuse = Fuselage()
         self.wing = Wing()
         self.components = [self.fuse, self.wing]
@@ -87,8 +87,9 @@ class FlightState(Model):
     rho   0.74     [kg/m^3]   air density
 
     """
+    @parse_variables(__doc__, globals())
     def setup(self):
-        exec(parse_variables(FlightState.__doc__))
+        pass
 
 
 class FlightSegment(Model):
@@ -165,10 +166,10 @@ class WingAero(Model):
     ---------------
     CL, wing.S, state.mu, state.rho, state.V
     """
+    @parse_variables(__doc__, globals())
     def setup(self, wing, state):
         self.wing = wing
         self.state = state
-        exec(parse_variables(WingAero.__doc__))
 
         c = wing.c
         A = wing.A
@@ -205,8 +206,8 @@ class Wing(Model):
     ---------------
     c, S
     """
+    @parse_variables(__doc__, globals())
     def setup(self):
-        exec(parse_variables(Wing.__doc__))
         return {"parametrization of wing weight":
                     W >= S*rho,
                 "definition of mean chord":
@@ -225,8 +226,9 @@ class Fuselage(Model):
     W  100 [lbf]  weight
 
     """
+    @parse_variables(__doc__, globals())
     def setup(self):
-        exec(parse_variables(Fuselage.__doc__))
+        pass
 
 AC = Aircraft()
 MISSION = Mission(AC)
@@ -239,7 +241,7 @@ def setup(self):
 sol.savetxt()
 sol.save("solution.pkl")
 # retrieve solution from a file
-sol_loaded = pickle.load(open("solution.pkl"))
+sol_loaded = pickle.load(open("solution.pkl", "rb"))
 
 vars_of_interest = set(AC.varkeys)
 # note that there's two ways to access submodels

gpkit/__init__.py

@@ -17,6 +17,7 @@
 from .constraints.model import Model
 from .tools.docstring import parse_variables
 
+
 GPBLU = "#59ade4"
 GPCOLORS = ["#59ade4", "#FA3333"]
 

gpkit/constraints/set.py

@@ -262,6 +262,8 @@ def process_result(self, result):
 
     def __repr__(self):
         "Returns namespaced string."
+        if not self:
+            return "<gpkit.%s object>" % self.__class__.__name__
         return ("<gpkit.%s object containing %i top-level constraint(s)"
                 " and %i variable(s)>" % (self.__class__.__name__,
                                           len(self), len(self.varkeys)))

gpkit/repr_conventions.py

@@ -10,11 +10,13 @@
 
 if sys.version_info >= (3, 0):
     unichr = chr  # pylint: disable=redefined-builtin,invalid-name
-
-
-PI_STR = "PI"  # fails on some external models if it's "π"
-UNICODE_EXPONENTS = False
-UNIT_FORMATTING = ":~"  # ":P~" for unicode exponents in units
+    PI_STR = "π"  # fails on some external models if it's "π"
+    UNICODE_EXPONENTS = True
+    UNIT_FORMATTING = ":P~"  # ":P~" for unicode exponents in units
+else:
+    PI_STR = "PI"  # fails on some external models if it's "π"
+    UNICODE_EXPONENTS = False
+    UNIT_FORMATTING = ":~"  # ":P~" for unicode exponents in units
 
 
 def lineagestr(lineage, modelnums=True):

gpkit/solution_array.py

@@ -71,7 +71,7 @@ def tight_table(self, _, ntightconstrs=5, tight_senss=1e-2, **kwargs):
         return []
     title = "Tightest Constraints"
     data = [((-float("%+6.2g" % c.relax_sensitivity), str(c)),
-             "%+6.2g" % c.relax_sensitivity, c)
+             "%+6.2g" % c.relax_sensitivity, id(c), c)
             for c in self.model.flat() if c.relax_sensitivity >= tight_senss]
     if not data:
         lines = ["No constraints had a sensitivity above %+5.1g."
@@ -106,7 +106,7 @@ def constraint_table(data, sortbymodel=True, showmodels=True, **_):
     if not showmodels:
         excluded = ("units", "lineage")  # hide all of it
     models, decorated = {}, []
-    for sortby, openingstr, constraint in sorted(data):
+    for sortby, openingstr, _, constraint in sorted(data):
         model = lineagestr(constraint) if sortbymodel else ""
         if model not in models:
             models[model] = len(models)
@@ -176,11 +176,13 @@ def warnings_table(self, _, **kwargs):
                 lines += ["| for sweep %i |" % i]
             if wtype == "Unexpectedly Tight Constraints" and data[0][1]:
                 data = [(-int(1e5*c.relax_sensitivity),
-                         "%+6.2g" % c.relax_sensitivity, c) for _, c in data]
+                         "%+6.2g" % c.relax_sensitivity, id(c), c)
+                        for _, c in data]
                 lines += constraint_table(data, **kwargs)
             elif wtype == "Unexpectedly Loose Constraints" and data[0][1]:
                 data = [(-int(1e5*c.rel_diff),
-                         "%.4g %s %.4g" % c.tightvalues, c) for _, c in data]
+                         "%.4g %s %.4g" % c.tightvalues, id(c), c)
+                        for _, c in data]
                 lines += constraint_table(data, **kwargs)
             else:
                 for msg, _ in data:
@@ -507,8 +509,8 @@ def savetxt(self, filename="solution.txt", printmodel=True, **kwargs):
         "Saves solution table as a text file"
         with open(filename, "w") as f:
             if printmodel and self.model:
-                f.write(str(self.model).encode("utf-8"))
-            f.write(self.table(**kwargs).encode("utf-8"))
+                f.write(str(self.model))
+            f.write(self.table(**kwargs))
 
     def savecsv(self, showvars=None, filename="solution.csv", valcols=5,
                 **kwargs):
@@ -547,7 +549,7 @@ def savecsv(self, showvars=None, filename="solution.csv", valcols=5,
                         f.write(el + ",")
                     f.write(","*(valcols - len(vals.split())))
                     f.write((line[2].replace("[", "").replace("]", "").strip()
-                             + ",").encode("utf8"))
+                             + ","))
                     f.write(line[3].strip() + "\n")
 
     def subinto(self, posy):
@@ -789,7 +791,7 @@ def var_table(data, title, printunits=True, latex=False, rawlines=False,
                         valstr = valstr.replace(before, after)
                     if values_remaining <= 0:
                         spaces = (-values_remaining
-                                  * len(valstr)/(values_remaining + ncols))
+                                  * len(valstr)//(values_remaining + ncols))
                         valstr = valstr + "  ]" + " "*spaces
                     lines.append(["", valstr, "", ""])
         else:

gpkit/tests/t_examples.py

@@ -90,14 +90,14 @@ def test_performance_modeling(self, example):
         sol.table()
         sol.save("solution.pkl")
         sol.table()
-        sol_loaded = pickle.load(open("solution.pkl"))
+        sol_loaded = pickle.load(open("solution.pkl", "rb"))
         sol_loaded.table()
 
         sweepsol = m.sweep({example.AC.fuse.W: (50, 100, 150)}, verbosity=0)
         sweepsol.table()
         sweepsol.save("sweepsolution.pkl")
         sweepsol.table()
-        sol_loaded = pickle.load(open("sweepsolution.pkl"))
+        sol_loaded = pickle.load(open("sweepsolution.pkl", "rb"))
         sol_loaded.table()
 
     def test_sp_to_gp_sweep(self, example):

gpkit/tests/t_model.py

@@ -702,8 +702,8 @@ class Box(Model):
     ---------------
     w, d, h
     """
+    @parse_variables(__doc__, globals())
     def setup(self):
-        exec(parse_variables(Box.__doc__))
         return [V == h*w*d]
 
 
@@ -740,15 +740,11 @@ def test_modelcontainmentprinting(self):
     def test_no_naming_on_var_access(self):
         # make sure that analysis models don't add their names to
         # variables looked up from other models
-        if sys.version_info >= (3, 0):
-            with self.assertRaises(FutureWarning):
-                box = Box()
-        else:
-            box = Box()
-            area_bounds = BoxAreaBounds(box)
-            M = Model(box["V"], [box, area_bounds])
-            for var in ("h", "w", "d"):
-                self.assertEqual(len(M.variables_byname(var)), 1)
+        box = Box()
+        area_bounds = BoxAreaBounds(box)
+        M = Model(box["V"], [box, area_bounds])
+        for var in ("h", "w", "d"):
+            self.assertEqual(len(M.variables_byname(var)), 1)
 
 
 TESTS = [TestModelSolverSpecific, TestModelNoSolve]