remove networkx dependency

Author: kavigupta

README.md

@@ -63,7 +63,7 @@ scope_info = ast_scope.annotate(tree)
 graph = scope_info.static_dependency_graph
 ```
 
-which results in the following networkx DiGraph of dependencies between top-level functions:
+which results in the following directed graph of dependencies between top-level functions (rendering using networkx):
 
 <img src="img/dependency_graph_example.png">
 

ast_scope/annotate.py

@@ -1,9 +1,8 @@
 
-import networkx as nx
-
 from .annotator import AnnotateScope, IntermediateGlobalScope
 from .pull_scope import PullScopes
 from .utils import get_all_nodes, get_name
+from .graph import DiGraph
 
 class ScopeInfo:
     def __init__(self, tree, global_scope, error_scope, node_to_containing_scope):
@@ -27,7 +26,7 @@ def static_dependency_graph(self):
             any other variables.
         """
         variables = self.global_scope.symbols_in_frame
-        g = nx.DiGraph()
+        g = DiGraph()
         g.add_nodes_from(variables)
         varis = self.global_scope.variables
         for construct in varis.functions | varis.classes:

ast_scope/graph.py

@@ -0,0 +1,21 @@
+
+class DiGraph:
+    def __init__(self):
+        self.__adjacency_list = {}
+
+    def add_nodes_from(self, iterable):
+        for node in iterable:
+            self.add_node(node)
+
+    def add_node(self, node):
+        if node not in self.__adjacency_list:
+            self.__adjacency_list[node] = set()
+
+    def add_edge(self, source, target):
+        self.__adjacency_list[source].add(target)
+
+    def nodes(self):
+        return list(self.__adjacency_list)
+
+    def edges(self):
+        return list((source, target) for source, targets in self.__adjacency_list.items() for target in targets)

requirements.txt

@@ -1,6 +1,5 @@
 # Module
 attrs==19.3.0
-networkx==2.4
 
 # Tests
 nose==1.3.3

setup.py

@@ -23,7 +23,6 @@
     ],
     python_requires='>=3.5',
     install_requires=[
-        'attrs==19.3.0',
-        'networkx==2.4'
+        'attrs==19.3.0'
     ]
 )