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diff --git a/Doc/library/symtable.rst b/Doc/library/symtable.rst new file mode 100644 index 0000000..0082287 --- /dev/null +++ b/Doc/library/symtable.rst @@ -0,0 +1,187 @@ +: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 + + +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_vararg() + + Return ``True`` if the symbol is a star arg (receives varargs). + + .. method:: is_kewordarg() + + Return ``True`` if the symbol is a two-star arg (receives keyword + arguments). + + .. 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. |