There are two errors that this commit fixes:
* The parser was not correctly computing the offset and the string
source for E_LINECONT errors due to the incorrect usage of strtok().
* The parser was not correctly unwinding the call stack when a tokenizer
exception happened in rules involving optionals ('?', [...]) as we
always make them return valid results by using the comma operator. We
need to check first if we don't have an error before continuing.
The traceback.c and traceback.py mechanisms now utilize the newly added code.co_positions and PyCode_Addr2Location
to print carets on the specific expressions involved in a traceback.
Co-authored-by: Pablo Galindo <Pablogsal@gmail.com>
Co-authored-by: Ammar Askar <ammar@ammaraskar.com>
Co-authored-by: Batuhan Taskaya <batuhanosmantaskaya@gmail.com>
When the parser does a second pass to check for errors, these rules can
have some small side-effects as they may advance the parser more than
the point reached in the first pass. This can cause the tokenizer to ask
for extra tokens in interactive mode causing the tokenizer to show the
prompt instead of failing instantly.
To avoid this, add a new mode to the tokenizer that is activated in the
second pass and deactivates asking for new tokens when the interactive
line is finished. As the parsing should have reached the last line in
the first pass, the second pass should not need to ask for more tokens.
The invalid assignment rules are very delicate since the parser can
easily raise an invalid assignment when a keyword argument is provided.
As they are very deep into the grammar tree, is very difficult to
specify in which contexts these rules can be used and in which don't.
For that, we need to use a different version of the rule that doesn't do
error checking in those situations where we don't want the rule to raise
(keyword arguments and generator expressions).
We also need to check if we are in left-recursive rule, as those can try
to eagerly advance the parser even if the parse will fail at the end of
the expression. Failing to do this allows the parser to start parsing a
call as a tuple and incorrectly identify a keyword argument as an
invalid assignment, before it realizes that it was not a tuple after all.
To improve the user experience understanding what part of the error messages associated with SyntaxErrors is wrong, we can highlight the whole error range and not only place the caret at the first character. In this way:
>>> foo(x, z for z in range(10), t, w)
File "<stdin>", line 1
foo(x, z for z in range(10), t, w)
^
SyntaxError: Generator expression must be parenthesized
becomes
>>> foo(x, z for z in range(10), t, w)
File "<stdin>", line 1
foo(x, z for z in range(10), t, w)
^^^^^^^^^^^^^^^^^^^^
SyntaxError: Generator expression must be parenthesized
* Add source location attributes to alias.
* Move alias star construction to pegen helper.
Co-authored-by: blurb-it[bot] <43283697+blurb-it[bot]@users.noreply.github.com>
Co-authored-by: Pablo Galindo <Pablogsal@gmail.com>
Rename AST functions of pycore_ast.h to use the "_PyAST_" prefix.
Remove macros creating aliases without prefix. For example, Module()
becomes _PyAST_Module(). Update Grammar/python.gram to use
_PyAST_xxx() functions.
Oleg Iarygin
Pablo Galindo Salgado
Kumar Aditya
Weipeng Hong
Victor Stinner
Batuhan Taskaya
Ammar Askar
Serhiy Storchaka
Brandt Bucher
Nick Coghlan
Matthew Suozzo
Erlend Egeberg Aasland