| :mod:`symtable` --- Access to the compiler's symbol tables |
| ========================================================== |
| |
| .. module:: symtable |
| :synopsis: Interface to the compiler's internal symbol tables. |
| |
| .. moduleauthor:: Jeremy Hylton <jeremy@alum.mit.edu> |
| .. sectionauthor:: Benjamin Peterson <benjamin@python.org> |
| |
| |
| Symbol tables are generated by the compiler from AST just before bytecode is |
| generated. The symbol table is responsible for calculating the scope of every |
| identifier in the code. :mod:`symtable` provides an interface to examine these |
| tables. |
| |
| |
| Generating Symbol Tables |
| ------------------------ |
| |
| .. function:: symtable(code, filename, compile_type) |
| |
| Return the toplevel :class:`SymbolTable` for the Python source *code*. |
| *filename* is the name of the file containing the code. *compile_type* is |
| like the *mode* argument to :func:`compile`. |
| |
| |
| Examining Symbol Tables |
| ----------------------- |
| |
| .. class:: SymbolTable |
| |
| A namespace table for a block. The constructor is not public. |
| |
| .. method:: get_type() |
| |
| Return the type of the symbol table. Possible values are ``'class'``, |
| ``'module'``, and ``'function'``. |
| |
| .. method:: get_id() |
| |
| Return the table's identifier. |
| |
| .. method:: get_name() |
| |
| Return the table's name. This is the name of the class if the table is |
| for a class, the name of the function if the table is for a function, or |
| ``'top'`` if the table is global (:meth:`get_type` returns ``'module'``). |
| |
| .. method:: get_lineno() |
| |
| Return the number of the first line in the block this table represents. |
| |
| .. method:: is_optimized() |
| |
| Return ``True`` if the locals in this table can be optimized. |
| |
| .. method:: is_nested() |
| |
| Return ``True`` if the block is a nested class or function. |
| |
| .. method:: has_children() |
| |
| Return ``True`` if the block has nested namespaces within it. These can |
| be obtained with :meth:`get_children`. |
| |
| .. method:: has_exec() |
| |
| Return ``True`` if the block uses ``exec``. |
| |
| .. method:: has_import_start() |
| |
| Return ``True`` if the block uses a starred from-import. |
| |
| .. method:: get_identifiers() |
| |
| Return a list of names of symbols in this table. |
| |
| .. method:: lookup(name) |
| |
| Lookup *name* in the table and return a :class:`Symbol` instance. |
| |
| .. method:: get_symbols() |
| |
| Return a list of :class:`Symbol` instances for names in the table. |
| |
| .. method:: get_children() |
| |
| Return a list of the nested symbol tables. |
| |
| |
| .. class:: Function |
| |
| A namespace for a function or method. This class inherits |
| :class:`SymbolTable`. |
| |
| .. method:: get_parameters() |
| |
| Return a tuple containing names of parameters to this function. |
| |
| .. method:: get_locals() |
| |
| Return a tuple containing names of locals in this function. |
| |
| .. method:: get_globals() |
| |
| Return a tuple containing names of globals in this function. |
| |
| .. method:: get_frees() |
| |
| Return a tuple containing names of free variables in this function. |
| |
| |
| .. class:: Class |
| |
| A namespace of a class. This class inherits :class:`SymbolTable`. |
| |
| .. method:: get_methods() |
| |
| Return a tuple containing the names of methods declared in the class. |
| |
| |
| .. class:: Symbol |
| |
| An entry in a :class:`SymbolTable` corresponding to an identifier in the |
| source. The constructor is not public. |
| |
| .. method:: get_name() |
| |
| Return the symbol's name. |
| |
| .. method:: is_referenced() |
| |
| Return ``True`` if the symbol is used in its block. |
| |
| .. method:: is_imported() |
| |
| Return ``True`` if the symbol is created from an import statement. |
| |
| .. method:: is_parameter() |
| |
| Return ``True`` if the symbol is a parameter. |
| |
| .. method:: is_global() |
| |
| Return ``True`` if the symbol is global. |
| |
| .. method:: is_local() |
| |
| Return ``True`` if the symbol is local to its block. |
| |
| .. method:: is_free() |
| |
| Return ``True`` if the symbol is referenced in its block, but not assigned |
| to. |
| |
| .. method:: is_assigned() |
| |
| Return ``True`` if the symbol is assigned to in its block. |
| |
| .. method:: is_namespace() |
| |
| Return ``True`` if name binding introduces new namespace. |
| |
| If the name is used as the target of a function or class statement, this |
| will be true. |
| |
| Note that a single name can be bound to multiple objects. If the result |
| is ``True``, the name may also be bound to other objects, like an int or |
| list, that does not introduce a new namespace. |
| |
| .. method:: get_namespaces() |
| |
| Return a list of namespaces bound to this name. |
| |
| .. method:: get_namespace() |
| |
| Return the namespace bound to this name. If more than one namespace is |
| bound, a :exc:`ValueError` is raised. |