a preliminary version of WmlIterator

data/tools/wesnoth/wmliterator.py

@@ -0,0 +1,81 @@
+"""
+wmliterator.py -- Python routines for navigating a Battle For Wesnoth WML tree
+
+"""
+
+def parseQuotes(lines, lineno):
+    """return the line or multiline text if a quote spans multiple lines"""
+    text = lines[lineno]
+    span = 1
+    begincomment = text.find('#')
+    if begincomment < 0:
+        begincomment = None
+    beginquote = text[:begincomment].find('"')
+    while beginquote > 0:
+        endquote = -1
+        beginofend = beginquote+1
+        while endquote < 0:
+            endquote = text.find('"', beginofend)
+            if endquote < 0:
+                # todo: check for end of lines
+                text += '\n' + lines[lineno + span]
+                span += 1
+                beginofend = 0
+        begincomment = text.find('#', endquote+1)
+        if begincomment < 0:
+            begincomment = None
+        beginquote = text[:begincomment].find('"', endquote+1)
+    return text, span
+
+def parseElements(line, scope):
+    """remove any closed scopes, return a tuple of element names
+    and list of opened scopes"""
+    raise NotImplemented
+    return elements, openedScopes
+    
+class WmlIterator:
+    """Return an iterable WML navigation object.
+    note: if changes are made to lines while iterating, this may produce
+    unexpected results."""
+    def __init__(self, lines, begin=-1, end=None):
+        "Initialize a new WmlIterator"
+        self.lines = lines
+        if end is None:
+            self.end = len(lines)
+        else:
+            self.end = end
+        self.seek(begin)
+
+    def seek(self, lineno):
+        """Move the iterator to a specific line number"""
+        if lineno < 0 or lineno < self.lineno:
+            # moving backwards or to the beginning forces a reset
+            self.lineno = -1
+            self.scope = []
+            self.nextScope = []
+            self.text = ""
+            self.span = 1
+            self.element = ""
+        while self.lineno + self.span - 1 < lineno:
+            self.next()
+
+    def hasNext(self):
+        """some loops may wish to check this method instead of calling next()
+        and handling StopIteration"""
+        return self.end > self.lineno + self.span
+
+    def next(self):
+        """Move the iterator to the next line number
+        note: May raise StopIteration"""
+        if not self.hasNext():
+            raise StopIteration
+        self.lineno = self.lineno + self.span
+        self.text, self.span = parseQuotes(self.lines, self.lineno)
+        self.scope.extend(self.nextScope)
+        self.element, self.nextScope = parseElements(self.lines[self.lineno],
+                                                     self.scope)
+        if(len(self.element) == 1):
+            # currently we only wish to handle simple single assignment syntax
+            self.element = self.element[0]
+
+# wmliterator.py ends here