| # |
| # 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 |
