From 12f44596828fe0dc46b9fe2f7561e89038cd78ed Mon Sep 17 00:00:00 2001
From: Salvo 'LtWorf' Tomaselli <tiposchi@tiscali.it>
Date: Sat, 24 Jun 2017 13:01:22 +0200
Subject: [PATCH] More type information

Add type information, change some imports and some style.
---
 relational/maintenance.py | 45 ++++++++++++++++----------------
 relational/optimizer.py   | 27 +++++++------------
 relational/parser.py      | 39 +++++++++++++--------------
 relational/relation.py    | 55 ++++++++++++++++++++-------------------
 relational/rtypes.py      |  9 ++++---
 5 files changed, 83 insertions(+), 92 deletions(-)

diff --git a/relational/maintenance.py b/relational/maintenance.py
index 89b2229..3a4e501 100644
--- a/relational/maintenance.py
+++ b/relational/maintenance.py
@@ -23,8 +23,9 @@ import urllib.parse
 import os.path
 import pickle
 import base64
+from typing import Optional, Tuple
 
-from relational.relation import relation
+from relational.relation import Relation
 from relational import parser
 from relational.rtypes import is_valid_relation_name
 
@@ -32,7 +33,7 @@ from relational.rtypes import is_valid_relation_name
 SWEARWORDS = {'fuck', 'shit', 'suck', 'merda', 'mierda', 'merde'}
 
 
-def send_survey(data):
+def send_survey(data) -> int:
     '''Sends the survey. Data must be a dictionary.
     returns the http response.
 
@@ -60,7 +61,7 @@ def send_survey(data):
         return 0
 
 
-def check_latest_version():
+def check_latest_version() -> Optional[str]:
     '''Returns the latest version available.
     Heavely dependent on server and server configurations
     not granted to work forever.'''
@@ -78,30 +79,30 @@ def check_latest_version():
     return s.decode().strip()
 
 
-class UserInterface (object):
+class UserInterface:
 
     '''It is used to provide services to the user interfaces, in order to
     reduce the amount of duplicated code present in different user interfaces.
     '''
 
-    def __init__(self):
+    def __init__(self) -> None:
         self.session_reset()
 
-    def load(self, filename, name):
+    def load(self, filename: str, name: str) -> None:
         '''Loads a relation from file, and gives it a name to
         be used in subsequent queries.'''
-        rel = relation(filename)
+        rel = Relation(filename)
         self.set_relation(name, rel)
 
-    def unload(self, name):
+    def unload(self, name: str) -> None:
         '''Unloads an existing relation.'''
         del self.relations[name]
 
-    def store(self, filename, name):
+    def store(self, filename: str, name: str) -> None:
         '''Stores a relation to file.'''
-        pass
+        raise Exception('Not implemented')
 
-    def session_dump(self, filename=None):
+    def session_dump(self, filename: Optional[str] = None) -> Optional[str]:
         '''
         Dumps the session.
 
@@ -109,7 +110,7 @@ class UserInterface (object):
         inside the file, and None is returned.
 
         If no filename is specified, the session is returned
-        as bytes.
+        as string.
         '''
         if filename:
             with open(filename, 'w') as f:
@@ -117,11 +118,11 @@ class UserInterface (object):
                 return None
         return base64.b64encode(pickle.dumps(self.relations)).decode()
 
-    def session_restore(self, session=None, filename=None):
+    def session_restore(self, session: Optional[bytes] = None, filename: Optional[str] = None) -> None:
         '''
         Restores a session.
 
-        Either from bytes or from a file
+        Either from bytes or from a file.
         '''
         if session:
             try:
@@ -132,23 +133,23 @@ class UserInterface (object):
             with open(filename) as f:
                 self.relations = pickle.load(f)
 
-    def session_reset(self):
+    def session_reset(self) -> None:
         '''
         Resets the session to a clean one
         '''
         self.relations = {}
 
-    def get_relation(self, name):
+    def get_relation(self, name: str) -> Relation:
         '''Returns the relation corresponding to name.'''
         return self.relations[name]
 
-    def set_relation(self, name, rel):
+    def set_relation(self, name: str, rel: Relation) -> None:
         '''Sets the relation corresponding to name.'''
         if not is_valid_relation_name(name):
             raise Exception('Invalid name for destination relation')
         self.relations[name] = rel
 
-    def suggest_name(self, filename):
+    def suggest_name(self, filename: str) -> Optional[str]:
         '''
         Returns a possible name for a relation, given
         a filename.
@@ -167,7 +168,7 @@ class UserInterface (object):
             return None
         return name
 
-    def execute(self, query, relname='last_'):
+    def execute(self, query: str, relname: str = 'last_') -> Relation:
         '''Executes a query, returns the result and if
         relname is not None, adds the result to the
         dictionary, with the name given in relname.'''
@@ -180,7 +181,7 @@ class UserInterface (object):
         return result
 
     @staticmethod
-    def split_query(query, default_name='last_'):
+    def split_query(query: str, default_name='last_') -> Tuple[str, str]:
         '''
         Accepts a query which might have an initial value
         assignment
@@ -196,14 +197,14 @@ class UserInterface (object):
             query = sq[1].strip()
         return default_name, query
 
-    def multi_execute(self, query):
+    def multi_execute(self, query: str) -> Relation:
         '''Executes multiple queries, separated by \n
 
         They can have a syntax of
         [varname =] query
         to assign the result to a new relation
         '''
-        r = relation()
+        r = Relation()
         queries = query.split('\n')
         for query in queries:
             if query.strip() == '':
diff --git a/relational/optimizer.py b/relational/optimizer.py
index 1fb2ee1..3e8ccd5 100644
--- a/relational/optimizer.py
+++ b/relational/optimizer.py
@@ -22,32 +22,23 @@
 # relational query, or it can be a parse tree for a relational expression (ie: class parser.node).
 # The functions will always return a string with the optimized query, but if a parse tree was provided,
 # the parse tree itself will be modified accordingly.
+from typing import Union, Optional, Dict, Any
 
 from relational import optimizations
-from relational import parser
+from relational.parser import Node, RELATION, UNARY, BINARY, op_functions, tokenize, tree
 from relational import querysplit
 from relational.maintenance import UserInterface
 
-
-# Stuff that was here before, keeping it for compatibility
-RELATION = parser.RELATION
-UNARY = parser.UNARY
-BINARY = parser.BINARY
-
-op_functions = parser.op_functions
-node = parser.node
-tokenize = parser.tokenize
-tree = parser.tree
-# End of the stuff
+ContextDict = Dict[str,Any]
 
 
-def optimize_program(code, rels):
+def optimize_program(code, rels: ContextDict):
     '''
     Optimize an entire program, composed by multiple expressions
     and assignments.
     '''
     lines = code.split('\n')
-    context = {}
+    context = {} #  type: ContextDict
 
     for line in  lines:
         line = line.strip()
@@ -55,14 +46,14 @@ def optimize_program(code, rels):
             continue
         res, query = UserInterface.split_query(line)
         last_res = res
-        parsed = parser.tree(query)
+        parsed = tree(query)
         optimizations.replace_leaves(parsed, context)
         context[res] = parsed
     node = optimize_all(context[last_res], rels, tostr=False)
     return querysplit.split(node, rels)
 
 
-def optimize_all(expression, rels, specific=True, general=True, debug=None,tostr=True):
+def optimize_all(expression: Union[str, Node], rels: ContextDict, specific: bool = True, general: bool = True, debug: Optional[list] = None, tostr: bool = True) -> Union[str, Node]:
     '''This function performs all the available optimizations.
 
     expression : see documentation of this module
@@ -76,7 +67,7 @@ def optimize_all(expression, rels, specific=True, general=True, debug=None,tostr
     Return value: this will return an optimized version of the expression'''
     if isinstance(expression, str):
         n = tree(expression)  # Gets the tree
-    elif isinstance(expression, node):
+    elif isinstance(expression, Node):
         n = expression
     else:
         raise (TypeError("expression must be a string or a node"))
@@ -107,7 +98,7 @@ def optimize_all(expression, rels, specific=True, general=True, debug=None,tostr
         return n
 
 
-def specific_optimize(expression, rels):
+def specific_optimize(expression, rels: ContextDict):
     '''This function performs specific optimizations. Means that it will need to
     know the fields used by the relations.
 
diff --git a/relational/parser.py b/relational/parser.py
index 340ed8a..8409bf8 100644
--- a/relational/parser.py
+++ b/relational/parser.py
@@ -24,7 +24,7 @@
 #
 # Language definition here:
 # http://ltworf.github.io/relational/grammar.html
-from typing import Optional
+from typing import Optional, Union, List, Any
 
 from relational import rtypes
 
@@ -85,7 +85,7 @@ class CallableString(str):
         return eval(self, context)
 
 
-class Node (object):
+class Node:
 
     '''This class is a node of a relational expression. Leaves are relations
     and internal nodes are operations.
@@ -105,7 +105,7 @@ class Node (object):
     kind = None #  type: Optional[int]
     __hash__ = None #  type: None
 
-    def __init__(self, expression=None):
+    def __init__(self, expression: Optional[list] = None) -> None:
         '''Generates the tree from the tokenized expression
         If no expression is specified then it will create an empty node'''
         if expression == None or len(expression) == 0:
@@ -172,7 +172,7 @@ class Node (object):
         code = self._toPython()
         return compile(code, '<relational_expression>', 'eval')
 
-    def toPython(self):
+    def toPython(self) -> CallableString:
         '''This method converts the AST into a python code string, which
         will require the relation module to be executed.
 
@@ -180,7 +180,7 @@ class Node (object):
         directly called.'''
         return CallableString(self._toPython())
 
-    def _toPython(self):
+    def _toPython(self) -> str:
         '''
         Same as toPython but returns a regular string
         '''
@@ -201,7 +201,7 @@ class Node (object):
             return '%s.%s(%s)' % (self.child.toPython(), op_functions[self.name], prop)
         return self.name
 
-    def printtree(self, level=0):
+    def printtree(self, level: int = 0) -> str:
         '''returns a representation of the tree using indentation'''
         r = ''
         for i in range(level):
@@ -213,10 +213,9 @@ class Node (object):
         elif self.name in u_operators:
             r += '\t%s\n' % self.prop
             r += self.child.printtree(level + 1)
-
         return '\n' + r
 
-    def get_left_leaf(self):
+    def get_left_leaf(self) -> 'Node':
         '''This function returns the leftmost leaf in the tree.'''
         if self.kind == RELATION:
             return self
@@ -225,12 +224,12 @@ class Node (object):
         elif self.kind == BINARY:
             return self.left.get_left_leaf()
 
-    def result_format(self, rels):
+    def result_format(self, rels: dict) -> list:
         '''This function returns a list containing the fields that the resulting relation will have.
         It requires a dictionary where keys are the names of the relations and the values are
         the relation objects.'''
-        if rels == None:
-            return
+        if not isinstance(rels, dict):
+            raise TypeError('Can\'t be of None type')
 
         if self.kind == RELATION:
             return list(rels[self.name].header)
@@ -285,7 +284,7 @@ class Node (object):
             return (le + self.name + re)
 
 
-def _find_matching_parenthesis(expression, start=0, openpar=u'(', closepar=u')'):
+def _find_matching_parenthesis(expression: str, start=0, openpar=u'(', closepar=u')') -> int:
     '''This function returns the position of the matching
     close parenthesis to the 1st open parenthesis found
     starting from start (0 by default)'''
@@ -304,7 +303,6 @@ def _find_matching_parenthesis(expression, start=0, openpar=u'(', closepar=u')')
         if string:
             continue
 
-
         if expression[i] == openpar:
             par_count += 1
         elif expression[i] == closepar:
@@ -312,7 +310,7 @@ def _find_matching_parenthesis(expression, start=0, openpar=u'(', closepar=u')')
             if par_count == 0:
                 return i  # Closing parenthesis of the parameter
 
-def _find_token(haystack, needle):
+def _find_token(haystack: str, needle: str) -> int:
     '''
     Like the string function find, but
     ignores tokens that are within a string
@@ -337,17 +335,17 @@ def _find_token(haystack, needle):
     return r
 
 
-def tokenize(expression):
+def tokenize(expression: str) -> list:
     '''This function converts a relational expression into a list where
     every token of the expression is an item of a list. Expressions into
     parenthesis will be converted into sublists.'''
 
-    items = []  # List for the tokens
+    # List for the tokens
+    items = [] #  type: List[Union[str,list]]
 
     expression = expression.strip()  # Removes initial and ending spaces
 
     while len(expression) > 0:
-
         if expression.startswith('('):  # Parenthesis state
             end = _find_matching_parenthesis(expression)
             if end == None:
@@ -384,17 +382,16 @@ def tokenize(expression):
                     break
             items.append(expression[:r])
             expression = expression[r:].strip()
-
     return items
 
 
-def tree(expression):
+def tree(expression: str) -> Node:
     '''This function parses a relational algebra expression into a AST and returns
     the root node using the Node class.'''
-    return node(tokenize(expression))
+    return Node(tokenize(expression))
 
 
-def parse(expr):
+def parse(expr: str) -> CallableString:
     '''This function parses a relational algebra expression, and returns a
     CallableString (a string that can be called) whith the corresponding
     Python expression.
diff --git a/relational/relation.py b/relational/relation.py
index dd88afb..52b3986 100644
--- a/relational/relation.py
+++ b/relational/relation.py
@@ -22,6 +22,7 @@
 import csv
 from itertools import chain, repeat
 from collections import deque
+from typing import List, Union
 
 from relational.rtypes import *
 
@@ -52,9 +53,9 @@ class Relation (object):
     '''
     __hash__ = None #  type: None
 
-    def __init__(self, filename=""):
+    def __init__(self, filename : str = '') -> None:
         self._readonly = False
-        self.content = set()
+        self.content = set() #  type: Set[tuple]
 
         if len(filename) == 0:  # Empty relation
             self.header = Header([])
@@ -65,14 +66,14 @@ class Relation (object):
             iterator = ((self.insert(i) for i in reader))
             deque(iterator, maxlen=0)
 
-    def _make_duplicate(self, copy):
+    def _make_duplicate(self, copy: 'Relation') -> None:
         '''Flag that the relation "copy" is pointing
         to the same set as this relation.'''
 
         self._readonly = True
         copy._readonly = True
 
-    def _make_writable(self, copy_content=True):
+    def _make_writable(self, copy_content : bool = True) -> None:
         '''If this relation is marked as readonly, this
         method will copy the content to make it writable too
 
@@ -91,7 +92,7 @@ class Relation (object):
     def __contains__(self, key):
         return key in self.content
 
-    def save(self, filename):
+    def save(self, filename: str) -> None:
         '''
         Saves the relation in a file. Will save using the csv
         format as defined in RFC4180.
@@ -107,7 +108,7 @@ class Relation (object):
             # Writing content, already in the correct format
             writer.writerows(self.content)
 
-    def _rearrange(self, other):
+    def _rearrange(self, other: 'Relation') -> 'Relation':
         '''If two relations share the same attributes in a different order, this method
         will use projection to make them have the same attributes' order.
         It is not exactely related to relational algebra. Just a method used
@@ -123,7 +124,7 @@ class Relation (object):
             ','.join(self.header), ','.join(other.header)
         ))
 
-    def selection(self, expr):
+    def selection(self, expr: str) -> 'Relation':
         '''
         Selection, expr must be a valid Python expression; can contain field names.
         '''
@@ -149,7 +150,7 @@ class Relation (object):
                     "Failed to evaluate %s\n%s" % (expr, e.__str__()))
         return newt
 
-    def product(self, other):
+    def product(self, other: 'Relation') -> 'Relation':
         '''
         Cartesian product. Attributes of the relations must differ.
         '''
@@ -168,7 +169,7 @@ class Relation (object):
                 newt.content.add(i + j)
         return newt
 
-    def projection(self, * attributes):
+    def projection(self, * attributes) -> 'Relation':
         '''
         Can be called in two different ways:
         a.projection('field1','field2')
@@ -199,7 +200,7 @@ class Relation (object):
             newt.content.add(tuple(row))
         return newt
 
-    def rename(self, params):
+    def rename(self, params: 'Relation') -> 'Relation':
         '''
         Takes a dictionary.
 
@@ -215,7 +216,7 @@ class Relation (object):
         self._make_duplicate(newt)
         return newt
 
-    def intersection(self, other):
+    def intersection(self, other: 'Relation') -> 'Relation':
         '''
         Intersection operation. The result will contain items present in both
         operands.
@@ -228,7 +229,7 @@ class Relation (object):
         newt.content = self.content.intersection(other.content)
         return newt
 
-    def difference(self, other):
+    def difference(self, other: 'Relation') -> 'Relation':
         '''Difference operation. The result will contain items present in first
         operand but not in second one.
         '''
@@ -239,7 +240,7 @@ class Relation (object):
         newt.content = self.content.difference(other.content)
         return newt
 
-    def division(self, other):
+    def division(self, other: 'Relation') -> 'Relation':
         '''Division operator
         The division is a binary operation that is written as R ÷ S. The
         result consists of the restrictions of tuples in R to the
@@ -265,7 +266,7 @@ class Relation (object):
         t = self.projection(d_headers).product(other)
         return self.projection(d_headers).difference(t.difference(self).projection(d_headers))
 
-    def union(self, other):
+    def union(self, other: 'Relation') -> 'Relation':
         '''Union operation. The result will contain items present in first
         and second operands.
         '''
@@ -276,18 +277,18 @@ class Relation (object):
         newt.content = self.content.union(other.content)
         return newt
 
-    def thetajoin(self, other, expr):
+    def thetajoin(self, other: 'Relation', expr: str) -> 'Relation':
         '''Defined as product and then selection with the given expression.'''
         return self.product(other).selection(expr)
 
-    def outer(self, other):
+    def outer(self, other: 'Relation') -> 'Relation':
         '''Does a left and a right outer join and returns their union.'''
         a = self.outer_right(other)
         b = self.outer_left(other)
 
         return a.union(b)
 
-    def outer_right(self, other):
+    def outer_right(self, other: 'Relation') -> 'Relation':
         '''
         Outer right join. Considers self as left and param as right. If the
         tuple has no corrispondence, empy attributes are filled with a "---"
@@ -297,7 +298,7 @@ class Relation (object):
         '''
         return other.outer_left(self)
 
-    def outer_left(self, other, swap=False):
+    def outer_left(self, other: 'Relation', swap=False) -> 'Relation':
         '''
         See documentation for outer_right
         '''
@@ -338,7 +339,7 @@ class Relation (object):
 
         return newt
 
-    def join(self, other):
+    def join(self, other: 'Relation') -> 'Relation':
         '''
         Natural join, joins on shared attributes (one or more). If there are no
         shared attributes, it will behave as the cartesian product.
@@ -412,7 +413,7 @@ class Relation (object):
 
         return res
 
-    def update(self, expr, dic):
+    def update(self, expr: str, dic: dict) -> int:
         '''
         Updates certain values of a relation.
 
@@ -444,7 +445,7 @@ class Relation (object):
         self.content = not_affected.content
         return len(affected)
 
-    def insert(self, values):
+    def insert(self, values: Union[list,tuple]) -> int:
         '''
         Inserts a tuple in the relation.
         This function will not insert duplicate tuples.
@@ -468,7 +469,7 @@ class Relation (object):
         self.content.add(tuple(map(rstring, values)))
         return len(self.content) - prevlen
 
-    def delete(self, expr):
+    def delete(self, expr: str) -> int:
         '''
         Delete, expr must be a valid Python expression; can contain field names.
 
@@ -504,7 +505,7 @@ class Header(tuple):
     def __repr__(self):
         return "Header(%s)" % super(Header, self).__repr__()
 
-    def rename(self, params):
+    def rename(self, params) -> 'Header':
         '''Returns a new header, with renamed fields.
 
         params is a dictionary of {old:new} names
@@ -520,19 +521,19 @@ class Header(tuple):
                 raise Exception('Field not found: %s' % old)
         return Header(attrs)
 
-    def sharedAttributes(self, other):
+    def sharedAttributes(self, other: 'Header') -> int:
         '''Returns how many attributes this header has in common with a given one'''
         return len(set(self).intersection(set(other)))
 
-    def union(self, other):
+    def union(self, other) -> set:
         '''Returns the union of the sets of attributes with another header.'''
         return set(self).union(set(other))
 
-    def intersection(self, other):
+    def intersection(self, other) -> set:
         '''Returns the set of common attributes with another header.'''
         return set(self).intersection(set(other))
 
-    def getAttributesId(self, param):
+    def getAttributesId(self, param) -> List[int]:
         '''Returns a list with numeric index corresponding to field's name'''
         try:
             return [self.index(i) for i in param]
diff --git a/relational/rtypes.py b/relational/rtypes.py
index dea4a44..001be15 100644
--- a/relational/rtypes.py
+++ b/relational/rtypes.py
@@ -23,11 +23,12 @@
 import datetime
 import keyword
 import re
+from typing import Union
 
 RELATION_NAME_REGEXP = re.compile(r'^[_a-z][_a-z0-9]*$', re.IGNORECASE)
 
 
-class Rstring (str):
+class Rstring(str):
 
     '''String subclass with some custom methods'''
 
@@ -37,7 +38,7 @@ class Rstring (str):
         r'^([0-9]{1,4})(\\|-|/)([0-9]{1,2})(\\|-|/)([0-9]{1,2})$'
     )
 
-    def autocast(self):
+    def autocast(self) -> Union[int, float, 'Rdate', 'Rstring']:
         '''
         Returns the automatic cast for this
         value.
@@ -47,7 +48,7 @@ class Rstring (str):
         except:
             pass
 
-        self._autocast = self
+        self._autocast = self #  type: Union[int, float, 'Rdate', 'Rstring']
         if len(self) > 0:
             if self.isInt():
                 self._autocast = int(self)
@@ -80,7 +81,7 @@ class Rstring (str):
         no more parsings are needed
         '''
         try:
-            return self._isdate
+            return self._isdate #  type: ignore
         except:
             pass