Bugfix and move plugin to python specific ftplugin

Move to python specific plugin (ftplugin),
Fixed bug regarding empty buffer.

ftplugin/python/pythonhelper.py

@@ -0,0 +1,214 @@
+"""
+Simple analyzer for python source files. Collect and give info about file
+structure: classes, its methods and functions.
+
+version: 0.2
+date: 2016-05-21
+author: Roman Dobosz <gryf@vimja.com>
+
+TODO: - fix the corner case with applying a tag, where it shouldn't do. like:
+
+1    def foo():
+2        pass
+3
+4    if True == False:
+5        foo()
+
+where line 5 is reporting as a function foo() body, which is not true.
+
+"""
+from collections import OrderedDict
+import re
+
+import vim
+
+
+RE_TAG_TYPE = re.compile(r'\s*(def|class)[ \t]+([^(:]+).*')
+RE_INDENT = re.compile(r'([ \t]*).*')
+
+
+class PythonTag(object):
+    """A simple storage class representing a python tag."""
+
+    def __init__(self, tag_type='', full_name='', line_number=0,
+                 indent_level=0):
+        """Initializes instances of Python tags.
+
+        :param tag_type: Tag type as string
+        :param full_name: Full tag name (in dotted notation)
+        :param line_number: line number on which the tag starts
+        :param indent_level: indentation level of the tag (number)
+        """
+        self.tag_type = tag_type
+        self.name = full_name.split(".")[-1]
+        self.full_name = full_name
+        self.line_number = line_number
+        self.indent_level = indent_level
+
+    def __str__(self):
+        """Returns a string representation of the tag."""
+        return "%0.2d [%d] %s %s" % (self.line_number,
+                                     self.indent_level,
+                                     self.tag_type,
+                                     self.full_name)
+
+    __repr__ = __str__
+
+
+class EvenSimplerPythonTagsParser(object):
+    """Simplified version for Python source code tag parser."""
+
+    def get_tags(self):
+        """Return OrderedDict with all tags for current buffer"""
+        tags_stack = []
+        tags = OrderedDict()
+
+        for line_no, line in enumerate(vim.current.buffer):
+
+            tag_match = RE_TAG_TYPE.match(line)
+
+            if not tag_match:
+                continue
+
+            indent_level = self._get_indent_level(line)
+
+            for _ in range(len(tags_stack)):
+                if tags_stack and tags_stack[-1].indent_level >= indent_level:
+                    tags_stack.pop()
+
+                if not tags_stack:
+                    break
+
+            tag = PythonTag(tag_match.group(1),
+                            self._get_full_name(tags_stack,
+                                                tag_match.group(2)),
+                            line_no,
+                            indent_level)
+            tag.tag_type = self._get_tag_type(tag, tags_stack)
+
+            tags[line_no] = tag
+            tags_stack.append(tag)
+
+        return tags
+
+    def _get_tag_type(self, tag, tags_stack):
+        """Return proper type of the tag depending on context"""
+        if tag.tag_type == 'class':
+            return 'class'
+
+        if tags_stack and tags_stack[-1].tag_type == 'class':
+            return 'method'
+
+        return 'function'
+
+    def _get_full_name(self, tags_stack, name):
+        """Return full logical name dot separated starting from upper entity"""
+        if tags_stack:
+            return tags_stack[-1].full_name + "." + name
+
+        return name
+
+    def _get_indent_level(self, line):
+        """Return indentation level as a simple count of whitespaces"""
+        return len(RE_INDENT.match(line).group(1))
+
+
+class PythonHelper(object):
+    TAGS = {}
+
+    @classmethod
+    def find_tag(cls, buffer_number, changed_tick):
+        """
+        Tries to find the best tag for the current cursor position.
+
+        Parameters
+
+            buffer_number -- number of the current buffer
+
+            changed_tick -- always-increasing number used to indicate that the
+                buffer has been modified since the last time
+        """
+        tag = PythonHelper._get_tag(buffer_number, changed_tick)
+        update_vim_vars(tag)
+
+    @classmethod
+    def _get_tag(cls, buffer_number, changed_tick):
+        """Return the nearset tag object or None"""
+
+        if PythonHelper.TAGS.get(buffer_number) and \
+           PythonHelper.TAGS[buffer_number]['changed_tick'] == changed_tick:
+            tags = PythonHelper.TAGS[buffer_number]['tags']
+        else:
+            parser = EvenSimplerPythonTagsParser()
+            tags = parser.get_tags()
+            PythonHelper.TAGS['buffer_number'] = {'changed_tick': changed_tick,
+                                                  'tags': tags}
+
+        # get line number of current cursor position from Vim's internal data.
+        # It is always a positive number, starts from 1. Let's decrease it by
+        # one, so that it will not confuse us while operating vim interface by
+        # python, where everything starts from 0.
+        line_number = vim.current.window.cursor[0] - 1
+
+        while True:
+            try:
+                line = vim.current.buffer[line_number]
+            except IndexError:
+                return None
+
+            line_indent = len(RE_INDENT.match(line).group(1))
+            if line.strip():
+                break
+            # line contains nothing but white characters, looking up to grab
+            # some more context
+            line_number -= 1
+
+        tag = tags.get(line_number)
+
+        # if we have something at the beginning of the line, just return it;
+        # it doesn't matter if it is the tag found there or not
+        if line_indent == 0 or tag:
+            return tag
+
+        # get nearest tag
+        for line_no in range(line_number - 1, 0, -1):
+            tag = tags.get(line_no)
+            line = vim.current.buffer[line_no]
+            upper_line_indent = len(RE_INDENT.match(line).group(1))
+
+            if tag and upper_line_indent < line_indent:
+                return tag
+
+            if not line.strip():
+                continue
+
+            if upper_line_indent == 0:
+                return None
+
+            if upper_line_indent >= line_indent:
+                continue
+
+            if tag and tag.indent_level >= line_indent:
+                tag = None
+                continue
+
+        return tag
+
+    @classmethod
+    def delete_tags(cls, buffer_number):
+        """Removes tag data for the specified buffer number."""
+        del PythonHelper.TAGS[buffer_number]
+
+
+def update_vim_vars(tag):
+    """Update Vim variable usable with vimscript side of the plugin"""
+
+    if not tag:
+        vim.command('let w:PHStatusLine=""')
+        vim.command('let w:PHStatusLineTag=""')
+        vim.command('let w:PHStatusLineType=""')
+    else:
+        vim.command('let w:PHStatusLine="%s (%s)"' % (tag.full_name,
+                                                      tag.tag_type))
+        vim.command('let w:PHStatusLineTag="%s"' % tag.tag_type)
+        vim.command('let w:PHStatusLineType="%s"' % tag.full_name)