add tags capability

lib/stitch_plan/stitch.py

@@ -7,7 +7,9 @@ from ..utils.geometry import Point
 
 
 class Stitch(Point):
-    def __init__(self, x, y=None, color=None, jump=False, stop=False, trim=False, color_change=False, tie_modus=0, no_ties=False):
+    """A stitch is a Point with extra information telling how to sew it."""
+
+    def __init__(self, x, y=None, color=None, jump=False, stop=False, trim=False, color_change=False, tie_modus=0, no_ties=False, tags=None):
         Point.__init__(self, x, y)
         self.color = color
         self.jump = jump
@@ -16,6 +18,9 @@ class Stitch(Point):
         self.color_change = color_change
         self.tie_modus = tie_modus
         self.no_ties = no_ties
+        self.tags = set()
+
+        self.add_tags(tags or [])
 
         # Allow creating a Stitch from a Point
         if isinstance(x, Point):
@@ -34,8 +39,32 @@ class Stitch(Point):
                                                                "NO TIES" if self.no_ties else " ",
                                                                "COLOR CHANGE" if self.color_change else " ")
 
+    def add_tags(self, tags):
+        for tag in tags:
+            self.add_tag(tag)
+
+    def add_tag(self, tag):
+        """Store arbitrary information about a stitch.
+
+        Tags can be used to store any information about a stitch.  This can be
+        used by other parts of the code to keep track of where a Stitch came
+        from.  The Stitch treats tags as opaque.
+
+        Use strings as tags.  Python automatically optimizes this kind of
+        usage of strings, and it doesn't have to constantly do string
+        comparisons.  More details here:
+
+          https://stackabuse.com/guide-to-string-interning-in-python
+        """
+        self.tags.add(tag)
+
+    def has_tag(self, tag):
+        return tag in self.tags
+
     def copy(self):
-        return Stitch(self.x, self.y, self.color, self.jump, self.stop, self.trim, self.color_change, self.tie_modus, self.no_ties)
+        return Stitch(self.x, self.y, self.color, self.jump, self.stop, self.trim, self.color_change, self.tie_modus, self.no_ties, self.tags)
 
     def __json__(self):
-        return vars(self)
+        attributes = dict(vars(self))
+        attributes['tags'] = list(attributes['tags'])
+        return attributes