add quick access methods for commands

lib/elements/element.py

@@ -210,6 +210,22 @@ class EmbroideryElement(object):
     def commands(self):
         return find_commands(self.node)
 
+    @cache
+    def get_commands(self, command):
+        return [c for c in self.commands if c.command == command]
+
+    @cache
+    def get_command(self, command):
+        commands = self.get_commands(command)
+
+        if len(commands) == 1:
+            return commands[0]
+        elif len(commands) > 1:
+            raise ValueError(_("%(id)s has more than one command of type '%(command)s' linked to it") %
+                                dict(id=self.node.get(id), command=command))
+        else:
+            return None
+
     def strip_control_points(self, subpath):
         return [point for control_before, point, control_after in subpath]
 

messages.po

@@ -8,7 +8,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: PROJECT VERSION\n"
 "Report-Msgid-Bugs-To: EMAIL@ADDRESS\n"
-"POT-Creation-Date: 2018-06-16 22:33-0400\n"
+"POT-Creation-Date: 2018-06-22 22:19-0400\n"
 "PO-Revision-Date: YEAR-MO-DA HO:MI+ZONE\n"
 "Last-Translator: FULL NAME <EMAIL@ADDRESS>\n"
 "Language-Team: LANGUAGE <LL@li.org>\n"
@@ -47,6 +47,10 @@ msgstr ""
 msgid "Expand"
 msgstr ""
 
+#, python-format
+msgid "%(id)s has more than one command of type '%(command)s' linked to it"
+msgstr ""
+
 msgid "TRIM after"
 msgstr ""