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
* pycore_ast.h no longer defines the Yield macro.
* Fix a compiler warning on Windows: "warning C4005: 'Yield': macro
redefinition".
* Python-ast.c now defines directly functions with their real
_Py_xxx() name, rather than xxx().
* Remove "#undef Yield" in C files including pycore_ast.h.
Remove the pyarena.h header file with functions:
* PyArena_New()
* PyArena_Free()
* PyArena_Malloc()
* PyArena_AddPyObject()
These functions were undocumented, excluded from the limited C API,
and were only used internally by the compiler.
Add pycore_pyarena.h header. Rename functions:
* PyArena_New() => _PyArena_New()
* PyArena_Free() => _PyArena_Free()
* PyArena_Malloc() => _PyArena_Malloc()
* PyArena_AddPyObject() => _PyArena_AddPyObject()
Remove parser functions using the "struct _mod" type, because the
AST C API was removed:
* PyParser_ASTFromFile()
* PyParser_ASTFromFileObject()
* PyParser_ASTFromFilename()
* PyParser_ASTFromString()
* PyParser_ASTFromStringObject()
These functions were undocumented and excluded from the limited C
API.
Add pycore_parser.h internal header file. Rename functions:
* PyParser_ASTFromFileObject() => _PyParser_ASTFromFile()
* PyParser_ASTFromStringObject() => _PyParser_ASTFromString()
These functions are no longer exported (replace PyAPI_FUNC() with
extern).
Remove also _PyPegen_run_parser_from_file() function. Update
test_peg_generator to use _PyPegen_run_parser_from_file_pointer()
instead.
Remove the compiler functions using "struct _mod" type, because the
public AST C API was removed:
* PyAST_Compile()
* PyAST_CompileEx()
* PyAST_CompileObject()
* PyFuture_FromAST()
* PyFuture_FromASTObject()
These functions were undocumented and excluded from the limited C API.
Rename functions:
* PyAST_CompileObject() => _PyAST_Compile()
* PyFuture_FromASTObject() => _PyFuture_FromAST()
Moreover, _PyFuture_FromAST() is no longer exported (replace
PyAPI_FUNC() with extern). _PyAST_Compile() remains exported for
test_peg_generator.
Remove also compatibility functions:
* PyAST_Compile()
* PyAST_CompileEx()
* PyFuture_FromAST()
These functions were undocumented and excluded from the limited C
API.
Most names defined by these header files were not prefixed by "Py"
and so could create names conflicts. For example, Python-ast.h
defined a "Yield" macro which was conflict with the "Yield" name used
by the Windows <winbase.h> header.
Use the Python ast module instead.
* Move Include/asdl.h to Include/internal/pycore_asdl.h.
* Move Include/Python-ast.h to Include/internal/pycore_ast.h.
* Remove ast.h header file.
* pycore_symtable.h no longer includes Python-ast.h.
Rename Include/symtable.h to to Include/internal/pycore_symtable.h,
don't export symbols anymore (replace PyAPI_FUNC and PyAPI_DATA with
extern) and rename functions:
* PyST_GetScope() to _PyST_GetScope()
* PySymtable_BuildObject() to _PySymtable_Build()
* PySymtable_Free() to _PySymtable_Free()
Remove PySymtable_Build(), Py_SymtableString() and
Py_SymtableStringObject() functions.
The Py_SymtableString() function was part the stable ABI by mistake
but it could not be used, since the symtable.h header file was
excluded from the limited C API.
The Python symtable module remains available and is unchanged.
No longer use deprecated aliases to functions:
* Replace PyObject_MALLOC() with PyObject_Malloc()
* Replace PyObject_REALLOC() with PyObject_Realloc()
* Replace PyObject_FREE() with PyObject_Free()
* Replace PyObject_Del() with PyObject_Free()
* Replace PyObject_DEL() with PyObject_Free()
These functions are considered not safe because they suppress all internal errors
and can return wrong result. PyDict_GetItemString and _PyDict_GetItemId can
also silence current exception in rare cases.
Remove no longer used _PyDict_GetItemId.
Add _PyDict_ContainsId and rename _PyDict_Contains into
_PyDict_Contains_KnownHash.
* Add new capability to the PEG parser to type variable assignments. For instance:
```
| a[asdl_stmt_seq*]=';'.small_stmt+ [';'] NEWLINE { a }
```
* Add new sequence types from the asdl definition (automatically generated)
* Make `asdl_seq` type a generic aliasing pointer type.
* Create a new `asdl_generic_seq` for the generic case using `void*`.
* The old `asdl_seq_GET`/`ast_seq_SET` macros now are typed.
* New `asdl_seq_GET_UNTYPED`/`ast_seq_SET_UNTYPED` macros for dealing with generic sequences.
* Changes all possible `asdl_seq` types to use specific versions everywhere.
* Remove the slice type.
* Make Slice a kind of the expr type instead of the slice type.
* Replace ExtSlice(slices) with Tuple(slices, Load()).
* Replace Index(value) with a value itself.
All non-terminal nodes in AST for expressions are now of the expr type.
The AST "Suite" node is no longer used and it can be removed from the ASDL definition and related structures (compiler, visitors, ...).
Co-Authored-By: Victor Stinner <vstinner@python.org>
Co-authored-by: Brett Cannon <54418+brettcannon@users.noreply.github.com>
Co-authored-by: Pablo Galindo <Pablogsal@gmail.com>
The symbol table handing of PEP572's assignment expressions is not resolving correctly the scope of some variables in presence of global/nonlocal keywords in conjunction with comprehensions.
With `symtable_visit_expr` now correctly adjusting the recursion depth for named
expressions, `symtable_handle_namedexpr` should be leaving it alone.
Also adds a new check to `PySymtable_BuildObject` that raises `SystemError`
if a successful first symbol analysis pass fails to keep the stack depth
accounting clean.
- drop TargetScopeError in favour of raising SyntaxError directly
as per the updated PEP 572
- comprehension iteration variables are explicitly local, but
named expression targets in comprehensions are nonlocal or
global. Raise SyntaxError as specified in PEP 572
- named expression targets in the outermost iterable of a
comprehension have an ambiguous target scope. Avoid resolving
that question now by raising SyntaxError. PEP 572
originally required this only for cases where the bound name
conflicts with the iteration variable in the comprehension,
but CPython can't easily restrict the exception to that case
(as it doesn't know the target variable names when visiting
the outermost iterator expression)
This commit contains the implementation of PEP570: Python positional-only parameters.
* Update Grammar/Grammar with new typedarglist and varargslist
* Regenerate grammar files
* Update and regenerate AST related files
* Update code object
* Update marshal.c
* Update compiler and symtable
* Regenerate importlib files
* Update callable objects
* Implement positional-only args logic in ceval.c
* Regenerate frozen data
* Update standard library to account for positional-only args
* Add test file for positional-only args
* Update other test files to account for positional-only args
* Add News entry
* Update inspect module and related tests
* Add tokenization of :=
- Add token to Include/token.h. Add token to documentation in Doc/library/token.rst.
- Run `./python Lib/token.py` to regenerate Lib/token.py.
- Update Parser/tokenizer.c: add case to handle `:=`.
* Add initial usage of := in grammar.
* Update Python.asdl to match the grammar updates. Regenerated Include/Python-ast.h and Python/Python-ast.c
* Update AST and compiler files in Python/ast.c and Python/compile.c. Basic functionality, this isn't scoped properly
* Regenerate Lib/symbol.py using `./python Lib/symbol.py`
* Tests - Fix failing tests in test_parser.py due to changes in token numbers for internal representation
* Tests - Add simple test for := token
* Tests - Add simple tests for named expressions using expr and suite
* Tests - Update number of levels for nested expressions to prevent stack overflow
* Update symbol table to handle NamedExpr
* Update Grammar to allow assignment expressions in if statements.
Regenerate Python/graminit.c accordingly using `make regen-grammar`
* Tests - Add additional tests for named expressions in RoundtripLegalSyntaxTestCase, based on examples and information directly from PEP 572
Note: failing tests are currently commented out (4 out of 24 tests currently fail)
* Tests - Add temporary syntax test failure tests in test_parser.py
Note: There is an outstanding TODO for this -- syntax tests need to be
moved to a different file (presumably test_syntax.py), but this is
covering what needs to be tested at the moment, and it's more convenient
to run a single test for the time being
* Add support for allowing assignment expressions as function argument annotations. Uncomment tests for these cases because they all pass now!
* Tests - Move existing syntax tests out of test_parser.py and into test_named_expressions.py. Refactor syntax tests to use unittest
* Add TargetScopeError exception to extend SyntaxError
Note: This simply creates the TargetScopeError exception, it is not yet
used anywhere
* Tests - Update tests per PEP 572
Continue refactoring test suite:
The named expression test suite now checks for any invalid cases that
throw exceptions (no longer limited to SyntaxErrors), assignment tests
to ensure that variables are properly assigned, and scope tests to
ensure that variable availability and values are correct
Note:
- There are still tests that are marked to skip, as they are not yet
implemented
- There are approximately 300 lines of the PEP that have not yet been
addressed, though these may be deferred
* Documentation - Small updates to XXX/todo comments
- Remove XXX from child description in ast.c
- Add comment with number of previously supported nested expressions for
3.7.X in test_parser.py
* Fix assert in seq_for_testlist()
* Cleanup - Denote "Not implemented -- No keyword args" on failing test case. Fix PEP8 error for blank lines at beginning of test classes in test_parser.py
* Tests - Wrap all file opens in `with...as` to ensure files are closed
* WIP: handle f(a := 1)
* Tests and Cleanup - No longer skips keyword arg test. Keyword arg test now uses a simpler test case and does not rely on an external file. Remove print statements from ast.c
* Tests - Refactor last remaining test case that relied on on external file to use a simpler test case without the dependency
* Tests - Add better description of remaning skipped tests. Add test checking scope when using assignment expression in a function argument
* Tests - Add test for nested comprehension, testing value and scope. Fix variable name in skipped comprehension scope test
* Handle restriction of LHS for named expressions - can only assign to LHS of type NAME. Specifically, restrict assignment to tuples
This adds an alternative set_context specifically for named expressions,
set_namedexpr_context. Thus, context is now set differently for standard
assignment versus assignment for named expressions in order to handle
restrictions.
* Tests - Update negative test case for assigning to lambda to match new error message. Add negative test case for assigning to tuple
* Tests - Reorder test cases to group invalid syntax cases and named assignment target errors
* Tests - Update test case for named expression in function argument - check that result and variable are set correctly
* Todo - Add todo for TargetScopeError based on Guido's comment (2b3acd37bd (r30472562))
* Tests - Add named expression tests for assignment operator in function arguments
Note: One of two tests are skipped, as function arguments are currently treating
an assignment expression inside of parenthesis as one child, which does
not properly catch the named expression, nor does it count arguments
properly
* Add NamedStore to expr_context. Regenerate related code with `make regen-ast`
* Add usage of NamedStore to ast_for_named_expr in ast.c. Update occurances of checking for Store to also handle NamedStore where appropriate
* Add ste_comprehension to _symtable_entry to track if the namespace is a comprehension. Initialize ste_comprehension to 0. Set set_comprehension to 1 in symtable_handle_comprehension
* s/symtable_add_def/symtable_add_def_helper. Add symtable_add_def to handle grabbing st->st_cur and passing it to symtable_add_def_helper. This now allows us to call the original code from symtable_add_def by instead calling symtable_add_def_helper with a different ste.
* Refactor symtable_record_directive to take lineno and col_offset as arguments instead of stmt_ty. This allows symtable_record_directive to be used for stmt_ty and expr_ty
* Handle elevating scope for named expressions in comprehensions.
* Handle error for usage of named expression inside a class block
* Tests - No longer skip scope tests. Add additional scope tests
* Cleanup - Update error message for named expression within a comprehension within a class. Update comments. Add assert for symtable_extend_namedexpr_scope to validate that we always find at least a ModuleScope if we don't find a Class or FunctionScope
* Cleanup - Add missing case for NamedStore in expr_context_name. Remove unused var in set_namedexpr_content
* Refactor - Consolidate set_context and set_namedexpr_context to reduce duplicated code. Special cases for named expressions are handled by checking if ctx is NamedStore
* Cleanup - Add additional use cases for ast_for_namedexpr in usage comment. Fix multiple blank lines in test_named_expressions
* Tests - Remove unnecessary test case. Renumber test case function names
* Remove TargetScopeError for now. Will add back if needed
* Cleanup - Small comment nit for consistency
* Handle positional argument check with named expression
* Add TargetScopeError exception definition. Add documentation for TargetScopeError in c-api docs. Throw TargetScopeError instead of SyntaxError when using a named expression in a comprehension within a class scope
* Increase stack size for parser by 200. This is a minimal change (approx. 5kb) and should not have an impact on any systems. Update parser test to allow 99 nested levels again
* Add TargetScopeError to exception_hierarchy.txt for test_baseexception.py_
* Tests - Major update for named expression tests, both in test_named_expressions and test_parser
- Add test for TargetScopeError
- Add tests for named expressions in comprehension scope and edge cases
- Add tests for named expressions in function arguments (declarations
and call sites)
- Reorganize tests to group them more logically
* Cleanup - Remove unnecessary comment
* Cleanup - Comment nitpicks
* Explicitly disallow assignment expressions to a name inside parentheses, e.g.: ((x) := 0)
- Add check for LHS types to detect a parenthesis then a name (see note)
- Add test for this scenario
- Update tests for changed error message for named assignment to a tuple
(also, see note)
Note: This caused issues with the previous error handling for named assignment
to a LHS that contained an expression, such as a tuple. Thus, the check
for the LHS of a named expression must be changed to be more specific if
we wish to maintain the previous error messages
* Cleanup - Wrap lines more strictly in test file
* Revert "Explicitly disallow assignment expressions to a name inside parentheses, e.g.: ((x) := 0)"
This reverts commit f1531400ca7d7a2d148830c8ac703f041740896d.
* Add NEWS.d entry
* Tests - Fix error in test_pickle.test_exceptions by adding TargetScopeError to list of exceptions
* Tests - Update error message tests to reflect improved messaging convention (s/can't/cannot)
* Remove cases that cannot be reached in compile.c. Small linting update.
* Update Grammar/Tokens to add COLONEQUAL. Regenerate all files
* Update TargetScopeError PRE_INIT and POST_INIT, as this was purposefully left out when fixing rebase conflicts
* Add NamedStore back and regenerate files
* Pass along line number and end col info for named expression
* Simplify News entry
* Fix compiler warning and explicity mark fallthrough
* ast.h now includes Python-ast.h and node.h
* parsetok.h now includes node.h and grammar.h
* symtable.h now includes Python-ast.h
* Modify asdl_c.py to enhance Python-ast.h:
* Add #ifndef/#define Py_PYTHON_AST_H to be able to include the header
twice
* Add "extern { ... }" for C++
* Undefine "Yield" macro conflicting with winbase.h
* Remove "#undef Yield" from C files, it's now done in Python-ast.h
* Remove now useless includes in C files
If Py_BUILD_CORE is defined, the PyThreadState_GET() macro access
_PyRuntime which comes from the internal pycore_state.h header.
Public headers must not require internal headers.
Move PyThreadState_GET() and _PyInterpreterState_GET_UNSAFE() from
Include/pystate.h to Include/internal/pycore_state.h, and rename
PyThreadState_GET() to _PyThreadState_GET() there.
The PyThreadState_GET() macro of pystate.h is now redefined when
pycore_state.h is included, to use the fast _PyThreadState_GET().
Changes:
* Add _PyThreadState_GET() macro
* Replace "PyThreadState_GET()->interp" with
_PyInterpreterState_GET_UNSAFE()
* Replace PyThreadState_GET() with _PyThreadState_GET() in internal C
files (compiled with Py_BUILD_CORE defined), but keep
PyThreadState_GET() in the public header files.
* _testcapimodule.c: replace PyThreadState_GET() with
PyThreadState_Get(); the module is not compiled with Py_BUILD_CORE
defined.
* pycore_state.h now requires Py_BUILD_CORE to be defined.
Allow annotated global names in the module namespace after the symbol is
declared as global. Previously, only symbols annotated before they are declared
as global (i.e. inside a function) were allowed. This change allows symbols to be
declared as global before the annotation happens in the global scope.
When comprehensions switched to using a nested scope, the old
code for generating a temporary name to hold the accumulation
target became redundant, but was never actually removed.
Patch by Nitish Chandra.
The current behaviour of yield expressions inside comprehensions and
generator expressions is essentially an accident of implementation - it
arises implicitly from the way the compiler handles yield expressions inside
nested functions and generators.
Since the current behaviour wasn't deliberately designed, and is inherently
confusing, we're deprecating it, with no current plans to reintroduce it.
Instead, our advice will be to use a named nested generator definition
for cases where this behaviour is desired.
