`symtable` — 访问编译器的符号表 ¶

源代码： Lib/symtable.py

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. symtable provides an interface to examine these tables.

生成符号表 ¶

symtable. symtable ( code , filename , compile_type ) ¶: Return the toplevel SymbolTable for the Python source code . filename is the name of the file containing the code. compile_type is like the mode 自变量对于 compile() .

审查符号表 ¶

class symtable. SymbolTableType ¶

An enumeration indicating the type of a SymbolTable 对象。

MODULE = "module" ¶: Used for the symbol table of a module.

FUNCTION = "function" ¶: Used for the symbol table of a function.

CLASS = "class" ¶: Used for the symbol table of a class.

The following members refer to different flavors of annotation scopes .

ANNOTATION = "annotation" ¶: Used for annotations if from __future__ import annotations is active.

TYPE_ALIAS = "type alias" ¶: Used for the symbol table of type constructions.

TYPE_PARAMETERS = "type parameters" ¶: Used for the symbol table of generic functions or generic classes .

TYPE_VARIABLE = "type variable" ¶: Used for the symbol table of the bound, the constraint tuple or the default value of a single type variable in the formal sense, i.e., a TypeVar, a TypeVarTuple or a ParamSpec object (the latter two do not support a bound or a constraint tuple).

3.13 版添加。

class symtable. SymbolTable ¶

A namespace table for a block. The constructor is not public.

get_type ( ) ¶

Return the type of the symbol table. Possible values are members of the SymbolTableType 枚举。

3.12 版改变：添加 'annotation' , 'TypeVar bound' , 'type alias' ，和 'type parameter' as possible return values.

Changed in version 3.13: Return values are members of the SymbolTableType 枚举。

The exact values of the returned string may change in the future, and thus, it is recommended to use SymbolTableType members instead of hard-coded strings.

get_id ( ) ¶: Return the table’s identifier.

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 ( get_type() 返回 'module' ). For type parameter scopes (which are used for generic classes, functions, and type aliases), it is the name of the underlying class, function, or type alias. For type alias scopes, it is the name of the type alias. For TypeVar bound scopes, it is the name of the TypeVar .

get_lineno ( ) ¶: Return the number of the first line in the block this table represents.

is_optimized ( ) ¶: 返回 True if the locals in this table can be optimized.

is_nested ( ) ¶: 返回 True if the block is a nested class or function.

has_children ( ) ¶: 返回 True if the block has nested namespaces within it. These can be obtained with get_children() .

get_identifiers ( ) ¶: Return a view object containing the names of symbols in the table. See the 视图对象的文档编制 .

lookup ( 名称 ) ¶: Lookup name in the table and return a Symbol 实例。

get_symbols ( ) ¶: 返回列表化的 Symbol instances for names in the table.

get_children ( ) ¶: Return a list of the nested symbol tables.

class symtable. 函数 ¶

A namespace for a function or method. This class inherits from SymbolTable .

get_parameters ( ) ¶: Return a tuple containing names of parameters to this function.

get_locals ( ) ¶: Return a tuple containing names of locals in this function.

get_globals ( ) ¶: Return a tuple containing names of globals in this function.

get_nonlocals ( ) ¶: Return a tuple containing names of explicitly declared nonlocals in this function.

get_frees ( ) ¶: Return a tuple containing names of free (closure) variables in this function.

class symtable. 类 ¶

A namespace of a class. This class inherits from SymbolTable .

get_methods ( ) ¶

Return a tuple containing the names of method-like functions declared in the class.

Here, the term ‘method’ designates any function defined in the class body via def or async def .

Functions defined in a deeper scope (e.g., in an inner class) are not picked up by get_methods() .

例如：

>>> import symtable
>>> st = symtable.symtable('''
... def outer(): pass
...
... class A:
...    def f():
...        def w(): pass
...
...    def g(self): pass
...
...    @classmethod
...    async def h(cls): pass
...
...    global outer
...    def outer(self): pass
... ''', 'test', 'exec')
>>> class_A = st.get_children()[1]
>>> class_A.get_methods()
('f', 'g', 'h')

尽管 A().f() 引发 TypeError at runtime, A.f is still considered as a method-like function.

class symtable. Symbol ¶

An entry in a SymbolTable corresponding to an identifier in the source. The constructor is not public.

get_name ( ) ¶: Return the symbol’s name.

is_referenced ( ) ¶: 返回 True if the symbol is used in its block.

is_imported ( ) ¶: 返回 True if the symbol is created from an import statement.

is_parameter ( ) ¶: 返回 True if the symbol is a parameter.

is_global ( ) ¶: 返回 True if the symbol is global.

is_nonlocal ( ) ¶: 返回 True if the symbol is nonlocal.

is_declared_global ( ) ¶: 返回 True if the symbol is declared global with a global statement.

is_local ( ) ¶: 返回 True if the symbol is local to its block.

is_annotated ( ) ¶

返回 True if the symbol is annotated.

Added in version 3.6.

is_free ( ) ¶: 返回 True if the symbol is referenced in its block, but not assigned to.

is_assigned ( ) ¶: 返回 True if the symbol is assigned to in its block.

is_namespace ( ) ¶

返回 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.

例如：

>>> table = symtable.symtable("def some_func(): pass", "string", "exec")
>>> table.lookup("some_func").is_namespace()
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.

get_namespaces ( ) ¶: Return a list of namespaces bound to this name.

get_namespace ( ) ¶: Return the namespace bound to this name. If more than one or no namespace is bound to this name, a ValueError 被引发。

命令行用法 ¶

3.13 版添加。

The symtable module can be executed as a script from the command line.

python -m symtable [infile...]

Symbol tables are generated for the specified Python source files and dumped to stdout. If no input file is specified, the content is read from stdin.

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