Adding cython v0.20.2 in third-party.

third_party/cython/src/Cython/Compiler/TreeFragment.py

+#
+# TreeFragments - parsing of strings to trees
+#
+
+import re
+from StringIO import StringIO
+from Scanning import PyrexScanner, StringSourceDescriptor
+from Symtab import ModuleScope
+import PyrexTypes
+from Visitor import VisitorTransform
+from Nodes import Node, StatListNode
+from ExprNodes import NameNode
+import Parsing
+import Main
+import UtilNodes
+
+"""
+Support for parsing strings into code trees.
+"""
+
+class StringParseContext(Main.Context):
+    def __init__(self, name, include_directories=None):
+        if include_directories is None: include_directories = []
+        Main.Context.__init__(self, include_directories, {},
+                              create_testscope=False)
+        self.module_name = name
+
+    def find_module(self, module_name, relative_to = None, pos = None, need_pxd = 1):
+        if module_name not in (self.module_name, 'cython'):
+            raise AssertionError("Not yet supporting any cimports/includes from string code snippets")
+        return ModuleScope(module_name, parent_module = None, context = self)
+
+def parse_from_strings(name, code, pxds={}, level=None, initial_pos=None,
+                       context=None, allow_struct_enum_decorator=False):
+    """
+    Utility method to parse a (unicode) string of code. This is mostly
+    used for internal Cython compiler purposes (creating code snippets
+    that transforms should emit, as well as unit testing).
+
+    code - a unicode string containing Cython (module-level) code
+    name - a descriptive name for the code source (to use in error messages etc.)
+
+    RETURNS
+
+    The tree, i.e. a ModuleNode. The ModuleNode's scope attribute is
+    set to the scope used when parsing.
+    """
+    if context is None:
+        context = StringParseContext(name)
+    # Since source files carry an encoding, it makes sense in this context
+    # to use a unicode string so that code fragments don't have to bother
+    # with encoding. This means that test code passed in should not have an
+    # encoding header.
+    assert isinstance(code, unicode), "unicode code snippets only please"
+    encoding = "UTF-8"
+
+    module_name = name
+    if initial_pos is None:
+        initial_pos = (name, 1, 0)
+    code_source = StringSourceDescriptor(name, code)
+
+    scope = context.find_module(module_name, pos = initial_pos, need_pxd = 0)
+
+    buf = StringIO(code)
+
+    scanner = PyrexScanner(buf, code_source, source_encoding = encoding,
+                     scope = scope, context = context, initial_pos = initial_pos)
+    ctx = Parsing.Ctx(allow_struct_enum_decorator=allow_struct_enum_decorator)
+
+    if level is None:
+        tree = Parsing.p_module(scanner, 0, module_name, ctx=ctx)
+        tree.scope = scope
+        tree.is_pxd = False
+    else:
+        tree = Parsing.p_code(scanner, level=level, ctx=ctx)
+
+    tree.scope = scope
+    return tree
+
+class TreeCopier(VisitorTransform):
+    def visit_Node(self, node):
+        if node is None:
+            return node
+        else:
+            c = node.clone_node()
+            self.visitchildren(c)
+            return c
+
+class ApplyPositionAndCopy(TreeCopier):
+    def __init__(self, pos):
+        super(ApplyPositionAndCopy, self).__init__()
+        self.pos = pos
+
+    def visit_Node(self, node):
+        copy = super(ApplyPositionAndCopy, self).visit_Node(node)
+        copy.pos = self.pos
+        return copy
+
+class TemplateTransform(VisitorTransform):
+    """
+    Makes a copy of a template tree while doing substitutions.
+
+    A dictionary "substitutions" should be passed in when calling
+    the transform; mapping names to replacement nodes. Then replacement
+    happens like this:
+     - If an ExprStatNode contains a single NameNode, whose name is
+       a key in the substitutions dictionary, the ExprStatNode is
+       replaced with a copy of the tree given in the dictionary.
+       It is the responsibility of the caller that the replacement
+       node is a valid statement.
+     - If a single NameNode is otherwise encountered, it is replaced
+       if its name is listed in the substitutions dictionary in the
+       same way. It is the responsibility of the caller to make sure
+       that the replacement nodes is a valid expression.
+
+    Also a list "temps" should be passed. Any names listed will
+    be transformed into anonymous, temporary names.
+
+    Currently supported for tempnames is:
+    NameNode
+    (various function and class definition nodes etc. should be added to this)
+
+    Each replacement node gets the position of the substituted node
+    recursively applied to every member node.
+    """
+
+    temp_name_counter = 0
+
+    def __call__(self, node, substitutions, temps, pos):
+        self.substitutions = substitutions
+        self.pos = pos
+        tempmap = {}
+        temphandles = []
+        for temp in temps:
+            TemplateTransform.temp_name_counter += 1
+            handle = UtilNodes.TempHandle(PyrexTypes.py_object_type)
+            tempmap[temp] = handle
+            temphandles.append(handle)
+        self.tempmap = tempmap
+        result = super(TemplateTransform, self).__call__(node)
+        if temps:
+            result = UtilNodes.TempsBlockNode(self.get_pos(node),
+                                              temps=temphandles,
+                                              body=result)
+        return result
+
+    def get_pos(self, node):
+        if self.pos:
+            return self.pos
+        else:
+            return node.pos
+
+    def visit_Node(self, node):
+        if node is None:
+            return None
+        else:
+            c = node.clone_node()
+            if self.pos is not None:
+                c.pos = self.pos
+            self.visitchildren(c)
+            return c
+
+    def try_substitution(self, node, key):
+        sub = self.substitutions.get(key)
+        if sub is not None:
+            pos = self.pos
+            if pos is None: pos = node.pos
+            return ApplyPositionAndCopy(pos)(sub)
+        else:
+            return self.visit_Node(node) # make copy as usual
+
+    def visit_NameNode(self, node):
+        temphandle = self.tempmap.get(node.name)
+        if temphandle:
+            # Replace name with temporary
+            return temphandle.ref(self.get_pos(node))
+        else:
+            return self.try_substitution(node, node.name)
+
+    def visit_ExprStatNode(self, node):
+        # If an expression-as-statement consists of only a replaceable
+        # NameNode, we replace the entire statement, not only the NameNode
+        if isinstance(node.expr, NameNode):
+            return self.try_substitution(node, node.expr.name)
+        else:
+            return self.visit_Node(node)
+
+def copy_code_tree(node):
+    return TreeCopier()(node)
+
+INDENT_RE = re.compile(ur"^ *")
+def strip_common_indent(lines):
+    "Strips empty lines and common indentation from the list of strings given in lines"
+    # TODO: Facilitate textwrap.indent instead
+    lines = [x for x in lines if x.strip() != u""]
+    minindent = min([len(INDENT_RE.match(x).group(0)) for x in lines])
+    lines = [x[minindent:] for x in lines]
+    return lines
+
+class TreeFragment(object):
+    def __init__(self, code, name="(tree fragment)", pxds={}, temps=[], pipeline=[], level=None, initial_pos=None):
+        if isinstance(code, unicode):
+            def fmt(x): return u"\n".join(strip_common_indent(x.split(u"\n")))
+
+            fmt_code = fmt(code)
+            fmt_pxds = {}
+            for key, value in pxds.iteritems():
+                fmt_pxds[key] = fmt(value)
+            mod = t = parse_from_strings(name, fmt_code, fmt_pxds, level=level, initial_pos=initial_pos)
+            if level is None:
+                t = t.body # Make sure a StatListNode is at the top
+            if not isinstance(t, StatListNode):
+                t = StatListNode(pos=mod.pos, stats=[t])
+            for transform in pipeline:
+                if transform is None:
+                    continue
+                t = transform(t)
+            self.root = t
+        elif isinstance(code, Node):
+            if pxds != {}: raise NotImplementedError()
+            self.root = code
+        else:
+            raise ValueError("Unrecognized code format (accepts unicode and Node)")
+        self.temps = temps
+
+    def copy(self):
+        return copy_code_tree(self.root)
+
+    def substitute(self, nodes={}, temps=[], pos = None):
+        return TemplateTransform()(self.root,
+                                   substitutions = nodes,
+                                   temps = self.temps + temps, pos = pos)
+
+class SetPosTransform(VisitorTransform):
+    def __init__(self, pos):
+        super(SetPosTransform, self).__init__()
+        self.pos = pos
+
+    def visit_Node(self, node):
+        node.pos = self.pos
+        self.visitchildren(node)
+        return node