symtable — Access to the compiler’s symbol tables¶
Source code: 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.
Generating Symbol Tables¶
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symtable.symtable(code, filename, compile_type)¶
- Return the toplevel - SymbolTablefor the Python source code. filename is the name of the file containing the code. compile_type is like the mode argument to- compile().
Examining Symbol Tables¶
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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 - 'class',- 'module', and- 'function'.
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get_id()¶
- Return the table’s identifier. 
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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()returns- 'module').
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get_lineno()¶
- Return the number of the first line in the block this table represents. 
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is_optimized()¶
- Return - Trueif the locals in this table can be optimized.
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is_nested()¶
- Return - Trueif the block is a nested class or function.
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has_children()¶
- Return - Trueif the block has nested namespaces within it. These can be obtained with- get_children().
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has_exec()¶
- Return - Trueif the block uses- exec.
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get_identifiers()¶
- Return a list of names of symbols in this table. 
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get_children()¶
- Return a list of the nested symbol tables. 
 
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class symtable.Function¶
- A namespace for a function or method. This class inherits - SymbolTable.- 
get_parameters()¶
- Return a tuple containing names of parameters to this function. 
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get_locals()¶
- Return a tuple containing names of locals in this function. 
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get_globals()¶
- Return a tuple containing names of globals in this function. 
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get_frees()¶
- Return a tuple containing names of free variables in this function. 
 
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class symtable.Class¶
- A namespace of a class. This class inherits - SymbolTable.- 
get_methods()¶
- Return a tuple containing the names of methods declared in the class. 
 
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class symtable.Symbol¶
- An entry in a - SymbolTablecorresponding to an identifier in the source. The constructor is not public.- 
get_name()¶
- Return the symbol’s name. 
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is_referenced()¶
- Return - Trueif the symbol is used in its block.
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is_imported()¶
- Return - Trueif the symbol is created from an import statement.
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is_parameter()¶
- Return - Trueif the symbol is a parameter.
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is_global()¶
- Return - Trueif the symbol is global.
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is_declared_global()¶
- Return - Trueif the symbol is declared global with a global statement.
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is_local()¶
- Return - Trueif the symbol is local to its block.
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is_free()¶
- Return - Trueif the symbol is referenced in its block, but not assigned to.
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is_assigned()¶
- Return - Trueif the symbol is assigned to in its block.
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is_namespace()¶
- Return - Trueif name binding introduces new namespace.- If the name is used as the target of a function or class statement, this will be true. - For example: - >>> 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.
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get_namespaces()¶
- Return a list of namespaces bound to this name. 
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get_namespace()¶
- Return the namespace bound to this name. If more than one namespace is bound, - ValueErroris raised.
 
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