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A.3 Unsupported Python constructs

The following constructs are not supported by Psyco. It does not mean that code containing them will fail; it merely means that any function using them cannot be compiled, and will thus be entierely run by the standard interpreter.

• "from xx import *"

• the exec statement -- in some cases you can use eval and/or compile instead, under the restrictions described in section A.2

• class definitions (all the code immediately within a class statement)

• functions with free or cell vars, which occur with Python's new nested scopes (as enabled by "from __future__ import nested_scopes"); this concerns both the function whose local variable is made visible to a subfunction, and the subfunction using such a local variable

• miscellaneous places where Python's bytecode compiler cannot optimize the local variables, most notably at the top-level of the modules (i.e. outsite any function)

• generators

Log files report unsupported constructs by giving the corresponding bytecode instruction number, which you can look up in the following table:

Bytecode	Instruction name	Appears in
82	LOAD_LOCALS	class definitions
84	IMPORT_STAR	from xx import *
85	EXEC_STMT	exec xx
86	YIELD_VALUE	generators' yield xx
90	STORE_NAME	non-optimizable scopes (e.g. at module top-level)
91	DELETE_NAME	non-optimizable scopes (e.g. at module top-level)
101	LOAD_NAME	non-optimizable scopes (e.g. at module top-level)
134	MAKE_CLOSURE	nested scopes
135	LOAD_CLOSURE	nested scopes
136	LOAD_DEREF	nested scopes
137	STORE_DEREF	nested scopes

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The Ultimate Psyco Guide

Previous: A.2 Patched functions Up: A. Caveats Next: B. Performance expectations

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Release 1.0, documentation updated on January 14, 2003.