use sage Feature rather than require_package

veerer/__init__.py

@@ -31,11 +31,6 @@
 from .linear_family import VeeringTriangulationLinearFamily
 from .automaton import FlipGraph, CoreAutomaton, ReducedCoreAutomaton, GeometricAutomaton, GeometricAutomatonSubspace
 from .flip_sequence import VeeringFlipSequence
-
-from .env import sage
-if sage is not None:
-    from .flat_structure import FlatVeeringTriangulation
-    from .layout import FlatVeeringTriangulationLayout
-    from .measured_train_track import MeasuredTrainTrack
-
-del sage
+from .flat_structure import FlatVeeringTriangulation
+from .layout import FlatVeeringTriangulationLayout
+from .measured_train_track import MeasuredTrainTrack

veerer/automaton.py

@@ -32,9 +32,7 @@
 from .linear_family import VeeringTriangulationLinearFamily
 from .constants import RED, BLUE, PURPLE, PROPERTIES_COLOURS, colour_to_char, colour_to_string
 from .permutation import perm_invert
-
-from . import env
-from .env import sage, require_package
+from .env import CHECK
 
 
 class Automaton(object):
@@ -517,7 +515,7 @@ def set_seed(self, state):
         state = self._seed_setup(state)
 
         # TODO: check to be removed
-        if env.CHECK:
+        if CHECK:
             state._check()
 
         if self._verbosity:
@@ -604,7 +602,7 @@ def run(self, max_size=None):
             new_flip = flip_branch[-1].pop()
 
             # TODO: check to be removed
-            if env.CHECK:
+            if CHECK:
                 T._check()
 
             if self._verbosity >= 2:
@@ -670,7 +668,7 @@ def run(self, max_size=None):
             self._flip_back(flip_back_data)
 
             # TODO: check to be removed
-            if env.CHECK:
+            if CHECK:
                 T._check()
             assert T == state_branch[-1], (T, state_branch[-1])
 
@@ -726,12 +724,12 @@ def _forward_flips(self, state):
 
     def _flip(self, flip_data):
         e = flip_data
-        self._state.flip(e, check=env.CHECK)
+        self._state.flip(e, check=CHECK)
         return True, e
 
     def _flip_back(self, flip_back_data):
         e = flip_back_data
-        self._state.flip_back(e, check=env.CHECK)
+        self._state.flip_back(e, check=CHECK)
 
 
 class CoreAutomaton(Automaton):
@@ -757,13 +755,13 @@ def _forward_flips(self, state):
     def _flip(self, flip_data):
         e, col = flip_data
         old_col = self._state.colour(e)
-        self._state.flip(e, col, check=env.CHECK)
+        self._state.flip(e, col, check=CHECK)
         flip_back_data = (e, old_col)
         return self._state.edge_has_curve(e), flip_back_data
 
     def _flip_back(self, flip_back_data):
         e, old_col = flip_back_data
-        self._state.flip_back(e, old_col, check=env.CHECK)
+        self._state.flip_back(e, old_col, check=CHECK)
 
 
 class ReducedCoreAutomaton(Automaton):
@@ -784,7 +782,7 @@ def _forward_flips(self, state):
         """
         ffe = state.purple_edges()
         # TODO: check to be removed
-        if env.CHECK:
+        if CHECK:
             assert ffe == state.forward_flippable_edges()
         return [(x, col) for x in ffe for col in (BLUE, RED)]
 
@@ -793,10 +791,10 @@ def _flip(self, flip_data):
         e, col = flip_data
 
         # TODO: check to be removed
-        if env.CHECK:
+        if CHECK:
             assert T.is_forward_flippable(e)
         old_col = self._state.colour(e)
-        self._state.flip(e, col, reduced=False, check=env.CHECK)
+        self._state.flip(e, col, reduced=False, check=CHECK)
 
         if not self._state.edge_has_curve(e):
             return False, (e, old_col, ())
@@ -821,7 +819,7 @@ def _flip(self, flip_data):
                 T._colouring[T._ep[d]] = PURPLE
 
             # assertions to be removed
-            if env.CHECK:
+            if CHECK:
                 assert not T.is_forward_flippable(e)
                 assert not T.is_forward_flippable(a)
                 assert not T.is_forward_flippable(c)
@@ -837,7 +835,7 @@ def _flip(self, flip_data):
                 T._colouring[T._ep[c]] = PURPLE
 
             # assertions to be removed
-            if env.CHECK:
+            if CHECK:
                 assert not T.is_forward_flippable(e)
                 assert not T.is_forward_flippable(b)
                 assert not T.is_forward_flippable(d)
@@ -849,7 +847,7 @@ def _flip_back(self, flip_back_data):
         for ee, ccol in recolorings:
             self._state._colouring[ee] = ccol
             self._state._colouring[self._state._ep[ee]] = ccol
-        self._state.flip_back(e, old_col, check=env.CHECK)
+        self._state.flip_back(e, old_col, check=CHECK)
 
 
 class GeometricAutomaton(Automaton):
@@ -900,15 +898,15 @@ def _flip(self, flip_data):
         assert all(self._state.colour(e) == self._state.colour(edges[0]) for e in edges)
         flip_back_data = (edges, self._state.colour(edges[0]))
         for e in edges:
-            self._state.flip(e, col, check=env.CHECK)
-        if env.CHECK and not self._state.is_geometric(backend=self._backend):
+            self._state.flip(e, col, check=CHECK)
+        if CHECK and not self._state.is_geometric(backend=self._backend):
             raise RuntimeError('that was indeed possible!')
         return True, flip_back_data
 
     def _flip_back(self, flip_back_data):
         edges, old_col = flip_back_data
         for e in edges:
-            self._state.flip_back(e, old_col, check=env.CHECK)
+            self._state.flip_back(e, old_col, check=CHECK)
 
 
 class GeometricAutomatonSubspace(Automaton):
@@ -970,8 +968,8 @@ def _flip(self, flip_data):
         assert all(self._state.colour(e) == self._state.colour(edges[0]) for e in edges)
         flip_back_data = (edges, self._state.colour(edges[0]))
         for e in edges:
-            self._state.flip(e, col, check=env.CHECK)
-        if env.CHECK:
+            self._state.flip(e, col, check=CHECK)
+        if CHECK:
             self._state._check(RuntimeError)
             if not self._state.is_geometric(backend=self._backend):
                 raise RuntimeError
@@ -980,4 +978,4 @@ def _flip(self, flip_data):
     def _flip_back(self, flip_back_data):
         edges, old_col = flip_back_data
         for e in edges:
-            self._state.flip_back(e, old_col, check=env.CHECK)
+            self._state.flip_back(e, old_col, check=CHECK)

veerer/env.py

@@ -1,10 +1,5 @@
 r"""
-Various environment modules.
-
-TESTS::
-
-    sage: from veerer.env import sage, flipper, surface_dynamics, ppl  # random output due to deprecation warnings from realalg
-
+Tests for optional packages used by veerer.
 """
 # ****************************************************************************
 #  This file is part of veerer
@@ -28,61 +23,20 @@
 
 CHECK = False
 
-import sage.all
-import sage
-import sage.misc.prandom as random
-from sage.structure.richcmp import op_LT, op_LE, op_EQ, op_NE, op_GT, op_GE, rich_to_bool
-
-
-try:
-    import surface_dynamics
-except ImportError:
-    surface_dynamics = None
-
-
-try:
-    import flipper
-except ImportError:
-    flipper = None
-
-try:
-    import curver
-except ImportError:
-    curver = None
-
-try:
-    import ppl
-except ImportError:
-    ppl = None
-
-
-try:
-    import PyNormaliz
-except ImportError:
-    PyNormaliz = None
-
-error_msg = {
-    'curver': 'the function {} can only be called when the package curver is installed.',
-
-    'surface_dynamics': 'the function {} only works when the package surface_dynamics is installed. See https://pypi.org/project/surface_dynamics/ for instructions.',
-
-    'flipper': 'the function {} only works when the package flipper is installed. See https://pypi.org/project/flipper/ for instructions',
-
-    'ppl': 'the function {} only works when the package pplpy is installed. See https://pypi.org/project/pplpy/ for instructions.',
-
-    'PyNormaliz': 'the function {} only works when the package PyNormaliz is installed.'
-    }
-
-missing_mods = {
-    'curver': curver is None,
-    'flipper': flipper is None,
-    'ppl': ppl is None,
-    'surface_dynamics': surface_dynamics is None,
-    'PyNormaliz': PyNormaliz is None
-    }
-
-# TODO: use the traceback to find out who called this function!
-# https://docs.python.org/2/library/traceback.html#traceback-examples
-def require_package(mod_name, caller):
-    if missing_mods[mod_name]:
-        raise ValueError(error_msg[mod_name].format(caller))
+from sage.features import PythonModule
+
+pyflatsurf_feature = PythonModule(
+    "pyflatsurf", url="https://github.com/flatsurf/flatsurf/#install-with-conda"
+)
+surface_dynamics_feature = PythonModule(
+    "surface-dynamics", url="https://flatsurf.github.io/surface-dynamics/#installation"
+) 
+flipper_feature = PythonModule(
+    "flipper", url="https://flipper.readthedocs.io/en/latest/user/install.html"
+)
+curver_feature = PythonModule(
+    "curver", url="https://curver.readthedocs.io/en/master/user/install.html"
+)
+pynormaliz_feature = PythonModule(
+    "PyNormaliz", url="https://github.com/Normaliz/PyNormaliz"
+)

veerer/features.py

@@ -0,0 +1,21 @@
+r"""
+Tests for optional packages used by veerer.
+"""
+
+from sage.features import PythonModule
+
+flatsurf_feature = PythonModule(
+    "flatsurf", url="https://flatsurf.github.io/sage-flatsurf/#installation"
+)
+surface_dynamics_feature = PythonModule(
+    "surface_dynamics", url="https://flatsurf.github.io/surface-dynamics/#installation"
+)
+flipper_feature = PythonModule(
+    "veerer", url="https://flatsurf.github.io/veerer/installation.html"
+)
+curver_feature = PythonModule(
+    "curver", url="https://curver.readthedocs.io/en/master/user/install.html"
+)
+pynormaliz_feature = PythonModule(
+    "PyNormaliz", url="https://github.com/Normaliz/PyNormaliz"
+)

veerer/flip_sequence.py

@@ -59,7 +59,7 @@
 from .constants import colour_from_char, colour_to_char, RED, BLUE, PURPLE, GREEN, HORIZONTAL, VERTICAL
 from .permutation import perm_init, perm_check, perm_id, perm_is_one, perm_preimage, perm_invert, perm_cycle_string, perm_compose, perm_pow, perm_conjugate
 from .veering_triangulation import VeeringTriangulation
-from .env import require_package, sage, ppl
+
 
 def flip_sequence_to_string(sequence):
     return " ".join("%d%s" % (e, colour_to_char(col)) for e,col in sequence)

veerer/linear_family.py

@@ -28,33 +28,21 @@
 import numbers
 from random import choice, shuffle
 
-from .env import sage, ppl
+from sage.structure.element import get_coercion_model, Matrix
+from sage.rings.integer_ring import ZZ
+from sage.rings.rational_field import QQ
+from sage.matrix.constructor import matrix
+from sage.geometry.polyhedron.constructor import Polyhedron
+from sage.arith.misc import gcd
+from sage.categories.number_fields import NumberFields
+
 from .constants import VERTICAL, HORIZONTAL, BLUE, RED
 from .permutation import perm_cycle_string, perm_cycles, perm_check, perm_conjugate, perm_on_list
 from .polyhedron import LinearExpressions, ConstraintSystem
 from .veering_triangulation import VeeringTriangulation
 
-
-if sage is not None:
-    from sage.structure.element import get_coercion_model
-    from sage.rings.integer_ring import ZZ
-    from sage.rings.rational_field import QQ
-    from sage.matrix.constructor import matrix
-    from sage.geometry.polyhedron.constructor import Polyhedron
-    from sage.arith.misc import gcd
-    from sage.categories.number_fields import NumberFields
-
-    cm = get_coercion_model()
-    _NumberFields = NumberFields()
-else:
-    matrix = None
-    Polyhedron = None
-    gcd = None
-    ZZ = None
-    QQ = None
-
-    cm = None
-    _NumberFields = None
+cm = get_coercion_model()
+_NumberFields = NumberFields()
 
 
 def subspace_are_equal(subspace1, subspace2, check=True):
@@ -210,7 +198,7 @@ def __init__(self, *args, mutable=False, check=True):
             t, colouring, subspace = args
         VeeringTriangulation.__init__(self, t, colouring, mutable=mutable, check=False)
 
-        if not isinstance(subspace, sage.structure.element.Matrix):
+        if not isinstance(subspace, Matrix):
             subspace = matrix(subspace)
 
         self._subspace = subspace