some details in cython/core as suggested by cython-lint (#109)

cython/SnapPy.pxi

@@ -67,7 +67,7 @@ ELIF REAL_TYPE == 'double':
         double default_vertex_epsilon
         double det_error_epsilon
     cdef real_to_string(Real x):
-        return '%.18f'%x
+        return '%.18f' % x
 
 # SnapPea declarations
 
@@ -746,7 +746,7 @@ cdef extern from "addl_code.h":
     extern void free_gluing_equations(int** equations, int num_rows)
     extern int* get_cusp_equation(c_Triangulation* manifold, int cusp_num, int m, int l, int* num_rows)
     extern void free_cusp_equation(int* equation)
-    extern c_Triangulation*    triangulate_link_complement_from_file(char* file_name, char *path)  except *
+    extern c_Triangulation* triangulate_link_complement_from_file(char* file_name, char *path)  except *
     extern c_Triangulation* fibered_manifold_associated_to_braid(int numStrands, int braidLength, int* word)  except *
     extern void set_tet_shapes(c_Triangulation* manifold, Complex* filled_shapes, Complex* complete_shapes)
     extern void set_target_holonomy(c_Triangulation* manifold, int theCuspIndex, Complex theTarget, int theRecomputeFlag)

cython/core/abelian_group.pyx

@@ -67,8 +67,8 @@ cdef class AbelianGroup():
     def __repr__(self):
         if len(self.divisors) == 0:
             return '0'
-        factors = ( ['Z/%d'%n for n in self.divisors if n != 0] +
-                    ['Z' for n in self.divisors if n == 0] )
+        factors = (['Z/%d' % n for n in self.divisors if n] +
+                   ['Z' for n in self.divisors if not n])
         return ' + '.join(factors)
 
     def __len__(self):
@@ -231,7 +231,8 @@ cdef class PresentationMatrix():
         """
         cdef temp, m, i, j, k, l
         while len(self._units) > 0:
-            for i,j in self._units: break
+            for i, j in self._units:
+                break
             col_support = [k for k in self._col_support[j] if k != i] + [i]
             row_entries = [(l, self._entries.get((i,l), 0))
                            for l in self._row_support[i]]

cython/core/basic.pyx

@@ -139,7 +139,7 @@ def to_byte_str(s):
 
 
 # Types of covering spaces
-cover_types = {1:"irregular", 2:"regular", 3:"cyclic"}
+cover_types = {1: "irregular", 2: "regular", 3: "cyclic"}
 
 # Paths
 manifold_path = manifold_paths[0] + os.sep
@@ -179,7 +179,7 @@ cdef public void uFatalError(const_char_ptr function,
     # uFatalError which is usually the root cause of the problem.
     if not PyErr_Occurred():
         raise SnapPeaFatalError('SnapPea crashed in function %s(), '
-                                'defined in %s.c.'%(function, file))
+                                'defined in %s.c.' % (function, file))
 
 # Global variables used for interrupt processing
 cdef public Boolean gLongComputationInProgress
@@ -257,7 +257,7 @@ cdef public int uQuery(const_char_ptr  message,
     #  from the user, but for now it is set up to return the default
     #  response, to facilitate batch computations.
     cdef char *default = <char *> responses[<int> default_response]
-    sys.stderr.write('Q: %s\nA:  %s\n'%(<char *> message, default))
+    sys.stderr.write('Q: %s\nA:  %s\n' % (<char *> message, default))
     return <int> default_response
 
 

cython/core/dirichlet.pyx

@@ -14,7 +14,7 @@ cdef (WEPolyhedron*, int) get_generators_from_bytes(
                          '"% Generators"')
     nums = []
     for line in data[1:]:
-        nums +=  line.split()
+        nums += line.split()
     num_gens = int(nums[0])
     nums.pop(0)
 
@@ -26,7 +26,7 @@ cdef (WEPolyhedron*, int) get_generators_from_bytes(
             for j in range(4):
                 for k in range(4):
                     num_string = nums.pop(0) # save a reference
-                    generators[i][j][k] =  <Real_struct>Real_from_string(
+                    generators[i][j][k] = <Real_struct>Real_from_string(
                         <char*>num_string)
     elif len(nums) == 8*num_gens:
         temp_gens = <MoebiusTransformation *>malloc(
@@ -171,7 +171,7 @@ cdef class CDirichletDomain():
             free_Dirichlet_domain(self.c_dirichlet_domain)
 
     def __repr__(self):
-        return '%d finite vertices, %d ideal vertices; %d edges; %d faces'%(
+        return '%d finite vertices, %d ideal vertices; %d edges; %d faces' % (
             self.num_finite_vertices(),
             self.num_ideal_vertices(),
             self.num_edges(),
@@ -500,7 +500,7 @@ cdef class CDirichletDomain():
     def view(self):
         if PolyhedronViewer:
             return ViewerWindow(PolyhedronViewer, facedicts=self.face_list(),
-                title='Dirichlet Domain of %s'%self.manifold_name)
+                title='Dirichlet Domain of %s' % self.manifold_name)
         else:
             raise RuntimeError('The PolyhedronViewer class '
                                'was not imported.')
@@ -629,10 +629,10 @@ cdef class CDirichletDomain():
 
     def _to_string(self):
         matrices = self.pairing_matrices()
-        result = '%% Generators\n%s\n'%len(matrices)
+        result = '%% Generators\n%s\n' % len(matrices)
         for matrix in matrices:
             for row in matrix:
-                result += ' %s\n'%' '.join([str(x) for x in row])
+                result += ' %s\n' % ' '.join(str(x) for x in row)
             result += '\n'
         return result
 
@@ -694,7 +694,8 @@ cdef class CDirichletDomain():
         output = stl(self.face_list(), model, cutout, num_subdivisions, shrink_factor, cutoff_radius)
         with open(filename, 'w') as output_file:
             for line in output:
-                if UI_callback is not None: UI_callback()
+                if UI_callback is not None:
+                    UI_callback()
                 output_file.write(line)
 
 

cython/core/fundamental_group.pyx

@@ -121,7 +121,7 @@ cdef class CFundamentalGroup():
         free_group_presentation(self.c_group_presentation)
 
     def __repr__(self):
-        return 'Generators:\n   %s\nRelators:\n   %s'%(
+        return 'Generators:\n   %s\nRelators:\n   %s' % (
             ','.join(self.generators()),
             '\n   '.join(self.relators()))
 

cython/core/manifold.pyx

@@ -200,7 +200,8 @@ cdef class Manifold(Triangulation):
         cdef result
         cdef Triangulation new_tri
 
-        if self.c_triangulation is NULL: return ""
+        if self.c_triangulation is NULL:
+            return ""
 
         copy_triangulation(self.c_triangulation,
                            &c_retriangulated_triangulation)
@@ -649,10 +650,11 @@ cdef class Manifold(Triangulation):
         """
         cdef int acc
         cdef solution_type
-        if self.c_triangulation is NULL: return 0
+        if self.c_triangulation is NULL:
+            return 0
         solution_type = self.solution_type()
         if solution_type in ('not attempted', 'no solution found'):
-            raise ValueError('Solution type is: %s'%solution_type)
+            raise ValueError('Solution type is: %s' % solution_type)
         IF HIGH_PRECISION is True:
             # must provide a start value to get the correct precision
             result = sum(
@@ -760,7 +762,8 @@ cdef class Manifold(Triangulation):
         cdef Real CS
         cdef int accuracy
 
-        if self.c_triangulation is NULL: return 0
+        if self.c_triangulation is NULL:
+            return 0
         get_CS_value(self.c_triangulation,
                      &is_known,
                      &CS,
@@ -888,7 +891,8 @@ cdef class Manifold(Triangulation):
         cdef int acc_rec_re, acc_rec_im, acc_log_re, acc_log_im
         cdef Boolean is_geometric
 
-        if self.c_triangulation is NULL: return []
+        if self.c_triangulation is NULL:
+            return []
 
         # The SnapPea kernel itself supports non-orientable manifolds,
         # but the extensions in snap and verify don't.
@@ -1173,9 +1177,8 @@ cdef class Manifold(Triangulation):
         if data_spec is None:
             return ListOnePerLine([self.cusp_info(i)
                                    for i in range(self.num_cusps())])
-        # Need to check that data_spec has string type or unicode type
-        # for backwards compatibility with python 2.7.
-        if type(data_spec) == type('') or type(data_spec) == type(u''):
+        # Need to check that data_spec has string type
+        if isinstance(data_spec, str):
             return [c[data_spec] for c in self.cusp_info()]
         cusp_index = valid_index(
             data_spec, self.num_cusps(),
@@ -1204,8 +1207,8 @@ cdef class Manifold(Triangulation):
             'shape': self._number_(shape),
             'shape_accuracy': current_shape_accuracy,
             'modulus': self._number_(modulus),
-            'holonomies':(self._number_(meridian), self._number_(longitude)),
-            'holonomy_accuracy':min(meridian_accuracy,longitude_accuracy)
+            'holonomies': (self._number_(meridian), self._number_(longitude)),
+            'holonomy_accuracy': min(meridian_accuracy,longitude_accuracy)
         }
 
         core_geodesic(self.c_triangulation, cusp_index,
@@ -1215,8 +1218,8 @@ cdef class Manifold(Triangulation):
             core_length = Complex2Number(c_core_length)
             core_length.accuracy = accuracy
             info.update({
-                'core_length' : self._number_(core_length),
-                'singularity_index':singularity_index
+                'core_length': self._number_(core_length),
+                'singularity_index': singularity_index
             })
 
         return CuspInfo(**info)
@@ -1498,7 +1501,7 @@ cdef class Manifold(Triangulation):
             max_segments = which_curve.max_segments
             which_curve = which_curve.index
 
-        new_name = to_byte_str(self.name() + '-%d'%which_curve)
+        new_name = to_byte_str(self.name() + '-%d' % which_curve)
         c_new_name = new_name
 
         dual_curves(self.c_triangulation,
@@ -1627,7 +1630,8 @@ cdef class Manifold(Triangulation):
         cdef long int p, q
         cdef c_Triangulation *c_canonized_triangulation
 
-        if self.c_triangulation is NULL: return False
+        if self.c_triangulation is NULL:
+            return False
 
         copy_triangulation(self.c_triangulation, &c_canonized_triangulation)
         proto_canonize(c_canonized_triangulation)
@@ -1666,18 +1670,18 @@ cdef class Manifold(Triangulation):
                                         &perm0, &perm1, &perm2, &perm3)
             ans.append(
                 {'index':i,
-                 'generators':(face0_gen, face1_gen, face2_gen, face3_gen),
-                 'neighbors':(neighbor0_idx, neighbor1_idx,
-                              neighbor2_idx, neighbor3_idx),
-                 'gluings': ( tuple([ perm0>>(2 * i) & 3 for i in range(4)]),
-                              tuple([ perm1>>(2 * i) & 3 for i in range(4)]),
-                              tuple([ perm2>>(2 * i) & 3 for i in range(4)]),
-                              tuple([ perm3>>(2 * i) & 3 for i in range(4)])),
-                 'corners': ( self._number_(Complex2Number(c0)),
-                              self._number_(Complex2Number(c1)),
-                              self._number_(Complex2Number(c2)),
-                              self._number_(Complex2Number(c3)) ),
-                 'generator_path':generator_path}
+                 'generators': (face0_gen, face1_gen, face2_gen, face3_gen),
+                 'neighbors': (neighbor0_idx, neighbor1_idx,
+                               neighbor2_idx, neighbor3_idx),
+                 'gluings': (tuple([ perm0>>(2 * i) & 3 for i in range(4)]),
+                             tuple([ perm1>>(2 * i) & 3 for i in range(4)]),
+                             tuple([ perm2>>(2 * i) & 3 for i in range(4)]),
+                             tuple([ perm3>>(2 * i) & 3 for i in range(4)])),
+                 'corners': (self._number_(Complex2Number(c0)),
+                             self._number_(Complex2Number(c1)),
+                             self._number_(Complex2Number(c2)),
+                             self._number_(Complex2Number(c3)) ),
+                 'generator_path': generator_path}
                 )
         return ans
 
@@ -1754,7 +1758,7 @@ cdef class Manifold(Triangulation):
         cdef NormalSurfaceList *surfaces
         cdef c_FuncResult result
         cdef int num_surfaces
-        cdef c_Triangulation  *pieces[2]
+        cdef c_Triangulation *pieces[2]
         cdef Manifold M0, M1
 
         if self.c_triangulation is NULL:
@@ -1771,7 +1775,7 @@ cdef class Manifold(Triangulation):
         if not (0 <= which_surface < num_surfaces):
             raise ValueError('SnapPea only found %d surfaces, but you asked for surface number %s.' % (num_surfaces, which_surface))
 
-        result =  split_along_normal_surface(surfaces, which_surface, pieces)
+        result = split_along_normal_surface(surfaces, which_surface, pieces)
         if result != func_OK:
             raise RuntimeError('SnapPea kernel failed when splitting open along the given surface.')
 

cython/core/triangulation.pyx

@@ -229,7 +229,7 @@ cdef class Triangulation():
         knot = spherogram.DTcodec(DT)
         c_triangulation = get_triangulation_from_PythonKLP(
             knot.KLPProjection(), remove_finite_vertices)
-        name = to_byte_str('%d'%crossings + alternation + '%d'%index)
+        name = to_byte_str('%d' % crossings + alternation + '%d' % index)
         set_triangulation_name(c_triangulation, name)
         self._set_DTcode(knot)
         self.set_c_triangulation(c_triangulation)
@@ -432,9 +432,11 @@ cdef class Triangulation():
         False
         """
         orientability = Orientability[get_orientability(self.c_triangulation)]
-        if orientability == 'orientable': return True
-        elif orientability == 'nonorientable': return False
-        else: return None
+        if orientability == 'orientable':
+            return True
+        if orientability == 'nonorientable':
+            return False
+        return None
 
     def copy(self):
         """
@@ -685,7 +687,7 @@ cdef class Triangulation():
         _to_string.
         """
         cdef c_Triangulation* c_triangulation = NULL
-        if not self.c_triangulation is NULL:
+        if self.c_triangulation is not NULL:
             raise ValueError('The Triangulation must be empty.')
         b_string = to_byte_str(string)
         c_triangulation = read_triangulation_from_string(b_string)
@@ -719,7 +721,7 @@ cdef class Triangulation():
             if c_terse.glues_to_old_tet[n]:
                 byte |= 1 << bit
             bit += 1
-            if bit%8 == 0:
+            if bit % 8 == 0:
                 byteseq.append(byte)
                 byte, bit = 0, 0
         if bit:
@@ -745,7 +747,7 @@ cdef class Triangulation():
         True
         """
         cdef c_Triangulation* c_triangulation = NULL
-        if not self.c_triangulation is NULL:
+        if self.c_triangulation is not NULL:
             raise ValueError('The Triangulation must be empty.')
         c_triangulation = triangulation_from_bytes(bytestring)
         self.set_c_triangulation(c_triangulation)
@@ -754,7 +756,7 @@ cdef class Triangulation():
         """
         """
         cdef c_Triangulation* c_triangulation = NULL
-        if not self.c_triangulation is NULL:
+        if self.c_triangulation is not NULL:
             raise ValueError('The Triangulation must be empty.')
         c_triangulation = unpickle_triangulation(bytestring)
         self.set_c_triangulation(c_triangulation)
@@ -804,7 +806,7 @@ cdef class Triangulation():
         True
         """
         cdef c_Triangulation* c_triangulation = NULL
-        if not self.c_triangulation is NULL:
+        if self.c_triangulation is not NULL:
             raise ValueError('The Triangulation must be empty.')
         c_triangulation = listlike_to_triangulation(tetrahedra_data,
                                                     num_or_cusps,
@@ -831,7 +833,7 @@ cdef class Triangulation():
         triangulation_isosig.
         """
 
-        if not self.c_triangulation is NULL:
+        if self.c_triangulation is not NULL:
             raise ValueError('The Triangulation must be empty.')
 
         match = is_decorated_isosig.match(isosig)
@@ -1051,7 +1053,8 @@ cdef class Triangulation():
         >>> M.name()
         '4_1'
         """
-        if self.c_triangulation is NULL: return
+        if self.c_triangulation is NULL:
+            return
         return to_str(get_triangulation_name(self.c_triangulation))
 
     def set_name(self, new_name):
@@ -1117,7 +1120,8 @@ cdef class Triangulation():
         >>> M.num_tetrahedra()
         2
         """
-        if self.c_triangulation is NULL: return 0
+        if self.c_triangulation is NULL:
+            return 0
         return get_num_tetrahedra(self.c_triangulation)
 
     def dehn_fill(self, filling_data, which_cusp=None):
@@ -1226,7 +1230,7 @@ cdef class Triangulation():
         if data_spec is None:
             return ListOnePerLine([self.cusp_info(i)
                                    for i in range(self.num_cusps())])
-        if type(data_spec) == type(''):
+        if isinstance(data_spec, str):
             return [c[data_spec] for c in self.cusp_info()]
         cusp_index = valid_index(
             data_spec, self.num_cusps(),