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PEP 671: Document QUERY_DEREF among implementation details

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Chris Angelico 2021-12-02 09:57:15 +11:00
parent 21f6993114
commit 2f8088c384
1 changed files with 4 additions and 4 deletions
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@ -167,11 +167,11 @@ calculated as the function begins.
When a parameter with a late-bound default is omitted, the function will begin
with the parameter unbound. The function begins by testing for each parameter
with a late-bound default using a new opcode QUERY_FAST, and if unbound,
evaluates the original expression. This opcode (available only for fast locals
and not for other types of variable) pushes True onto the stack if the given
with a late-bound default using a new opcode QUERY_FAST/QUERY_DEREF, and if
unbound, evaluates the original expression. This opcode (available only for
fast locals and closure variables) pushes True onto the stack if the given
local has a value, and False if not - meaning that it pushes False if LOAD_FAST
would raise UnboundLocalError and True if it would succeed.
or LOAD_DEREF would raise UnboundLocalError, and True if it would succeed.
Out-of-order variable references are permitted as long as the referent has a
value from an argument or early-bound default.