Formally allow instances to point to None (i.e. an 'empty' pattern)

masque/file/gdsii.py

@@ -100,7 +100,9 @@ def write(patterns: Pattern or List[Pattern],
     # Get a dict of id(pattern) -> pattern
     patterns_by_id = {id(pattern): pattern for pattern in patterns}
     for pattern in patterns:
-        patterns_by_id.update(pattern.referenced_patterns_by_id())
+        for i, p in pattern.referenced_patterns_by_id().items():
+            if p is not None:
+                patterns_by_id[i] = p
 
     disambiguate_func(patterns_by_id.values())
 
@@ -170,7 +172,9 @@ def dose2dtype(patterns: List[Pattern],
     # Get a dict of id(pattern) -> pattern
     patterns_by_id = {id(pattern): pattern for pattern in patterns}
     for pattern in patterns:
-        patterns_by_id.update(pattern.referenced_patterns_by_id())
+        for i, p in pattern.referenced_patterns_by_id().items():
+            if p is not None:
+                patterns_by_id[i] = p
 
     # Get a table of (id(pat), written_dose) for each pattern and subpattern
     sd_table = make_dose_table(patterns)
@@ -466,6 +470,8 @@ def _subpatterns_to_refs(subpatterns: List[SubPattern or GridRepetition]
                         ) -> List[gdsii.elements.ARef or gdsii.elements.SRef]:
     refs = []
     for subpat in subpatterns:
+        if subpat.pattern is None:
+            continue
         encoded_name = subpat.pattern.name
 
         # Note: GDS mirrors first and rotates second

masque/file/svg.py

@@ -61,6 +61,8 @@ def writefile(pattern: Pattern,
     # Now create a group for each row in sd_table (ie, each pattern + dose combination)
     #  and add in any Boundary and Use elements
     for pat in patterns_by_id.values():
+        if pat is None:
+            continue
         svg_group = svg.g(id=mangle_name(pat), fill='blue', stroke='red')
 
         for shape in pat.shapes:
@@ -75,6 +77,8 @@ def writefile(pattern: Pattern,
                 svg_group.add(path)
 
         for subpat in pat.subpatterns:
+            if subpat.pattern is None:
+                continue
             transform = 'scale({:g}) rotate({:g}) translate({:g},{:g})'.format(
                 subpat.scale, subpat.rotation, subpat.offset[0], subpat.offset[1])
             use = svg.use(href='#' + mangle_name(subpat.pattern), transform=transform)

masque/file/utils.py

@@ -38,6 +38,8 @@ def make_dose_table(patterns: List[Pattern], dose_multiplier: float=1.0) -> Set[
     dose_table = {(id(pattern), dose_multiplier) for pattern in patterns}
     for pattern in patterns:
         for subpat in pattern.subpatterns:
+            if subpat.pattern is None:
+                continue
             subpat_dose_entry = (id(subpat.pattern), subpat.dose * dose_multiplier)
             if subpat_dose_entry not in dose_table:
                 subpat_dose_table = make_dose_table([subpat.pattern], subpat.dose * dose_multiplier)

masque/pattern.py

@@ -151,7 +151,9 @@ class Pattern:
             A Pattern containing all the shapes and subpatterns for which the parameter
                 functions return True
         """
-        def do_subset(src):
+        def do_subset(src: Optional['Pattern']) -> Optional['Pattern']:
+            if src is None:
+                return None
             pat = Pattern(name=src.name)
             if shapes_func is not None:
                 pat.shapes = [s for s in src.shapes if shapes_func(s)]
@@ -165,6 +167,8 @@ class Pattern:
             pat = self.apply(do_subset)
         else:
             pat = do_subset(self)
+
+        assert(pat is not None)
         return pat
 
     def apply(self,
@@ -197,8 +201,12 @@ class Pattern:
         if pat_id not in memo:
             memo[pat_id] = None
             pat = func(self)
-            for subpat in pat.subpatterns:
-                subpat.pattern = subpat.pattern.apply(func, memo)
+            if pat is not None:
+                for subpat in pat.subpatterns:
+                    if subpat.pattern is None:
+                        subpat.pattern = func(None)
+                    else:
+                        subpat.pattern = subpat.pattern.apply(func, memo)
             memo[pat_id] = pat
         elif memo[pat_id] is None:
             raise PatternError('.apply() called on pattern with circular reference')
@@ -277,11 +285,12 @@ class Pattern:
             else:
                 sp_transform = False
 
-            subpattern.pattern = subpattern.pattern.dfs(visit_before=visit_before,
-                                                        visit_after=visit_after,
-                                                        transform=sp_transform,
-                                                        memo=memo,
-                                                        hierarchy=hierarchy + (self,))
+            if subpattern.pattern is not None:
+                subpattern.pattern = subpattern.pattern.dfs(visit_before=visit_before,
+                                                            visit_after=visit_after,
+                                                            transform=sp_transform,
+                                                            memo=memo,
+                                                            hierarchy=hierarchy + (self,))
 
         if visit_after is not None:
             pat = visit_after(pat, hierarchy=hierarchy, memo=memo, transform=transform)
@@ -311,7 +320,8 @@ class Pattern:
                         (shape.to_polygons(poly_num_points, poly_max_arclen)
                          for shape in old_shapes)))
         for subpat in self.subpatterns:
-            subpat.pattern.polygonize(poly_num_points, poly_max_arclen)
+            if subpat.pattern is not None:
+                subpat.pattern.polygonize(poly_num_points, poly_max_arclen)
         return self
 
     def manhattanize(self,
@@ -368,6 +378,8 @@ class Pattern:
 
         if recursive:
             for subpat in self.subpatterns:
+                if subpat.pattern is None:
+                    continue
                 subpat.pattern.subpatternize(recursive=True,
                                              norm_value=norm_value,
                                              exclude_types=exclude_types)
@@ -431,7 +443,8 @@ class Pattern:
         for subpat in self.subpatterns:
             if id(subpat.pattern) not in ids:
                 ids[id(subpat.pattern)] = subpat.pattern
-                ids.update(subpat.pattern.referenced_patterns_by_id())
+                if subpat.pattern is not None:
+                    ids.update(subpat.pattern.referenced_patterns_by_id())
         return ids
 
     def referenced_patterns_by_name(self) -> List[Tuple[str, 'Pattern']]:
@@ -446,7 +459,7 @@ class Pattern:
             List of `(pat.name, pat)` tuples for all referenced Pattern objects
         """
         pats_by_id = self.referenced_patterns_by_id()
-        pat_list = [(p.name, p) for p in pats_by_id.values()]
+        pat_list = [(p.name if p is not None else None, p) for p in pats_by_id.values()]
         return pat_list
 
     def get_bounds(self) -> Union[numpy.ndarray, None]:
@@ -496,6 +509,8 @@ class Pattern:
         self.subpatterns = []
         shape_counts = {}
         for subpat in subpatterns:
+            if subpat.pattern is None:
+                continue
             subpat.pattern.flatten()
             p = subpat.as_pattern()
 
@@ -839,7 +854,7 @@ class Pattern:
             if pat in memo:
                 return memo
 
-            children = set(sp.pattern for sp in pat.subpatterns)
+            children = set(sp.pattern for sp in pat.subpatterns if sp.pattern is not None)
             new_children = children - memo
             memo |= children
 

masque/repetition.py

@@ -298,6 +298,7 @@ class GridRepetition:
             A copy of self.pattern which has been scaled, rotated, repeated, etc.
              etc. according to this `GridRepetition`'s properties.
         """
+        assert(self.pattern is not None)
         patterns = []
 
         for a in range(self.a_count):
@@ -411,7 +412,7 @@ class GridRepetition:
         self.rotation *= -1
         return self
 
-    def get_bounds(self) -> numpy.ndarray or None:
+    def get_bounds(self) -> Optional[numpy.ndarray]:
         """
         Return a `numpy.ndarray` containing `[[x_min, y_min], [x_max, y_max]]`, corresponding to the
          extent of the `GridRepetition` in each dimension.
@@ -420,6 +421,8 @@ class GridRepetition:
         Returns:
             `[[x_min, y_min], [x_max, y_max]]` or `None`
         """
+        if self.pattern is None:
+            return None
         return self.as_pattern().get_bounds()
 
     def scale_by(self, c: float) -> 'GridRepetition':
@@ -496,6 +499,7 @@ class GridRepetition:
         Returns:
             self
         """
+        assert(self.pattern is not None)
         self.lock()
         self.pattern.deeplock()
         return self
@@ -510,6 +514,7 @@ class GridRepetition:
         Returns:
             self
         """
+        assert(self.pattern is not None)
         self.unlock()
         self.pattern.deepunlock()
         return self

masque/subpattern.py

@@ -55,7 +55,7 @@ class SubPattern:
 
     #TODO more documentation?
     def __init__(self,
-                 pattern: 'Pattern' or None,
+                 pattern: Optional['Pattern'],
                  offset: vector2 = (0.0, 0.0),
                  rotation: float = 0.0,
                  mirrored: List[bool] = None,
@@ -176,6 +176,7 @@ class SubPattern:
             A copy of self.pattern which has been scaled, rotated, etc. according to this
              `SubPattern`'s properties.
         """
+        assert(self.pattern is not None)
         pattern = self.pattern.deepcopy().deepunlock()
         pattern.scale_by(self.scale)
         [pattern.mirror(ax) for ax, do in enumerate(self.mirrored) if do]
@@ -242,7 +243,7 @@ class SubPattern:
         self.rotation *= -1
         return self
 
-    def get_bounds(self) -> numpy.ndarray or None:
+    def get_bounds(self) -> Optional[numpy.ndarray]:
         """
         Return a `numpy.ndarray` containing `[[x_min, y_min], [x_max, y_max]]`, corresponding to the
          extent of the `SubPattern` in each dimension.
@@ -251,6 +252,8 @@ class SubPattern:
         Returns:
             `[[x_min, y_min], [x_max, y_max]]` or `None`
         """
+        if self.pattern is None:
+            return None
         return self.as_pattern().get_bounds()
 
     def scale_by(self, c: float) -> 'SubPattern':
@@ -311,6 +314,7 @@ class SubPattern:
         Returns:
             self
         """
+        assert(self.pattern is not None)
         self.lock()
         self.pattern.deeplock()
         return self
@@ -325,6 +329,7 @@ class SubPattern:
         Returns:
             self
         """
+        assert(self.pattern is not None)
         self.unlock()
         self.pattern.deepunlock()
         return self