Add docstrings to compiler and parser

homotopy/compiler.py

@@ -6,7 +6,16 @@
 
 
 class Compiler(SnippetVisitor):
+    """
+    Compiler for snippets. Turns syntax tree into text.
+    """
     def visit_composite_snippet(self, composite_snippet):
+        """
+        Replace right site in the appropriate place in the left side.
+
+        :param composite_snippet: Composite snippet
+        :return: Text of left side replaced with right side
+        """
         left_side = snippetProvider[self.visit(composite_snippet.left)]
         right_side = snippetProvider[self.compile(composite_snippet.right)]
 
@@ -39,9 +48,21 @@ def expansion_function(match_object):
         return left_side
 
     def visit_simple_snippet(self, simple_snippet):
+        """
+        Compile simple snippet.
+
+        :param simple_snippet: Simple snippet
+        :return: Text of compile snippet
+        """
         return snippetProvider[simple_snippet.value]
 
     def compile(self, snippet):
+        """
+        Compile a snippet.
+
+        :param snippet: Snippet
+        :return: Text of compiled snippet
+        """
         compiled_snippet = self.visit(snippet)
 
         return re.sub(r'({{.*?}})', "", compiled_snippet)

homotopy/parser.py

@@ -2,13 +2,22 @@
 
 
 class Parser:
+    """
+    Class for parsing a string to produce a syntax tree.
+    """
     parameter_chars = "!@#$%:~"
     in_operator = '>'
     out_operator = '<'
     and_operator = '&'
 
     @staticmethod
     def parse(snippet_text):
+        """
+        Parsing a string to produce syntax tree.
+
+        :param snippet_text: Text to parse
+        :return: syntax tree instance corresponding to given text
+        """
         stack = []
         current_match = []
         last_operator = Parser.in_operator
@@ -44,6 +53,12 @@ def parse(snippet_text):
 
     @staticmethod
     def merge_stack(stack):
+        """
+        Helper method to combine two snippets on top of the stack.
+
+        :param stack: Stack
+        :return: None
+        """
         last_tree = stack.pop()
         if last_tree != SimpleSnippet(''):
             next_tree = stack.pop()