| 1 | """
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| 2 | util.py
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| 3 | """
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| 4 | from __future__ import print_function
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| 5 |
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| 6 | import sys
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| 7 | from mypy.nodes import (CallExpr, IfStmt, Block, Expression, MypyFile,
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| 8 | MemberExpr, IntExpr, NameExpr, ComparisonExpr)
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| 9 | from mypy.types import Instance, Type
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| 10 |
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| 11 | from typing import Any, Optional, List, Tuple, Union
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| 12 |
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| 13 | # Used by cppgen_pass and const_pass
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| 14 |
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| 15 | # mycpp/examples/small_str.py sorta works with this!
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| 16 | #SMALL_STR = True
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| 17 |
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| 18 | SMALL_STR = False
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| 19 |
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| 20 | SymbolPath = Tuple[str, ...]
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| 21 |
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| 22 |
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| 23 | def log(msg: str, *args: Any) -> None:
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| 24 | if args:
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| 25 | msg = msg % args
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| 26 | print(msg, file=sys.stderr)
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| 27 |
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| 28 |
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| 29 | def SymbolToString(parts: SymbolPath,
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| 30 | strip_package: bool = False,
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| 31 | delim: str = '::') -> str:
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| 32 | """
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| 33 | Join the given name path into a string with the given delimiter.
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| 34 | Use strip_package to remove the top-level directory (e.g. `core`, `ysh`)
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| 35 | when dealing with C++ namespaces.
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| 36 | """
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| 37 | if not strip_package:
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| 38 | return delim.join(parts)
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| 39 |
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| 40 | if len(parts) > 1:
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| 41 | return delim.join(('', ) + parts[1:])
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| 42 |
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| 43 | return parts[0]
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| 44 |
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| 45 |
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| 46 | def SplitPyName(name: str) -> SymbolPath:
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| 47 | ret = tuple(name.split('.'))
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| 48 | if len(ret) and ret[0] == 'mycpp':
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| 49 | # Drop the prefix 'mycpp.' if present. This makes names compatible with
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| 50 | # the examples that use testpkg.
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| 51 | return ret[1:]
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| 52 |
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| 53 | return ret
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| 54 |
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| 55 |
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| 56 | CaseList = List[Tuple[Expression, Block]]
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| 57 |
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| 58 | CaseError = Tuple[str, int, str]
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| 59 |
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| 60 |
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| 61 | def CollectSwitchCases(
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| 62 | module_path: str,
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| 63 | if_node: IfStmt,
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| 64 | out: CaseList,
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| 65 | errors: Optional[List[CaseError]] = None) -> Union[Block, int]:
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| 66 | """
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| 67 | The MyPy AST has a recursive structure for if-elif-elif rather than a
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| 68 | flat one. It's a bit confusing.
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| 69 |
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| 70 | Appends (expr, block) cases to out param, and returns the default
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| 71 | block, which has no expression.
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| 72 |
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| 73 | default block may be None.
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| 74 |
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| 75 | Returns False if there is no default block.
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| 76 | """
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| 77 | assert isinstance(if_node, IfStmt), if_node
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| 78 | assert len(if_node.expr) == 1, if_node.expr
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| 79 | assert len(if_node.body) == 1, if_node.body
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| 80 |
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| 81 | expr = if_node.expr[0]
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| 82 | body = if_node.body[0]
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| 83 |
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| 84 | if not isinstance(expr, CallExpr):
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| 85 | if errors is not None:
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| 86 | errors.append((module_path, expr.line,
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| 87 | 'Expected call like case(x), got %s' % expr))
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| 88 | return -1 # error code
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| 89 |
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| 90 | out.append((expr, body))
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| 91 |
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| 92 | if if_node.else_body:
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| 93 | first_of_block = if_node.else_body.body[0]
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| 94 | # BUG: this is meant for 'elif' only. But it also triggers for
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| 95 | #
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| 96 | # else:
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| 97 | # if 0:
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| 98 |
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| 99 | if isinstance(first_of_block, IfStmt):
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| 100 | return CollectSwitchCases(module_path, first_of_block, out, errors)
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| 101 | else:
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| 102 | # default case - no expression
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| 103 | return if_node.else_body
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| 104 |
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| 105 | return -2 # NO DEFAULT BLOCK
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| 106 |
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| 107 |
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| 108 | def ShouldSkipPyFile(node: MypyFile) -> bool:
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| 109 | # Skip some stdlib stuff. A lot of it is brought in by 'import
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| 110 | # typing'. These module are special; their contents are currently all
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| 111 | # built-in primitives.
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| 112 | return node.fullname in ('__future__', 'sys', 'types', 'typing', 'abc',
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| 113 | '_ast', 'ast', '_weakrefset', 'collections',
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| 114 | 'cStringIO', 're', 'builtins')
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| 115 |
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| 116 |
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| 117 | def IsStr(t: Type) -> bool:
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| 118 | """Helper to check if a type is a string."""
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| 119 | return isinstance(t, Instance) and t.type.fullname == 'builtins.str'
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| 120 |
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| 121 |
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| 122 | def _ShouldSkipIf(stmt: IfStmt) -> bool:
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| 123 | cond = stmt.expr[0]
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| 124 |
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| 125 | # Omit anything that looks like if __name__ == ...
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| 126 | if (isinstance(cond, ComparisonExpr) and
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| 127 | isinstance(cond.operands[0], NameExpr) and
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| 128 | cond.operands[0].name == '__name__'):
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| 129 | return True
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| 130 |
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| 131 | if isinstance(cond, NameExpr) and cond.name == 'TYPE_CHECKING':
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| 132 | # Omit if TYPE_CHECKING blocks. They contain type expressions that
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| 133 | # don't type check!
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| 134 | return True
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| 135 |
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| 136 | return False
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| 137 |
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| 138 |
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| 139 | def GetSpecialIfCondition(stmt: IfStmt) -> Optional[str]:
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| 140 | cond = stmt.expr[0]
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| 141 | if isinstance(cond, NameExpr) and cond.name == 'TYPE_CHECKING':
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| 142 | return cond.name
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| 143 |
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| 144 | if isinstance(cond, MemberExpr) and cond.name in ('PYTHON', 'CPP'):
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| 145 | return cond.name
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| 146 |
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| 147 | return None
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| 148 |
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| 149 |
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| 150 | def ShouldVisitIfExpr(stmt: IfStmt) -> bool:
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| 151 | if _ShouldSkipIf(stmt) or GetSpecialIfCondition(stmt) in ('PYTHON', 'CPP'):
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| 152 | return False
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| 153 |
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| 154 | cond = stmt.expr[0]
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| 155 | if isinstance(cond, IntExpr) and cond.value == 0:
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| 156 | return False
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| 157 |
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| 158 | return True
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| 159 |
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| 160 |
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| 161 | def ShouldVisitIfBody(stmt: IfStmt) -> bool:
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| 162 | if _ShouldSkipIf(stmt):
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| 163 | return False
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| 164 |
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| 165 | cond = stmt.expr[0]
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| 166 | if isinstance(cond, MemberExpr) and cond.name == 'PYTHON':
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| 167 | return False
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| 168 |
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| 169 | if isinstance(cond, IntExpr) and cond.value == 0:
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| 170 | return False
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| 171 |
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| 172 | return True
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| 173 |
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| 174 |
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| 175 | def ShouldVisitElseBody(stmt: IfStmt) -> bool:
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| 176 | if _ShouldSkipIf(stmt):
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| 177 | return False
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| 178 |
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| 179 | cond = stmt.expr[0]
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| 180 | if isinstance(cond, MemberExpr) and cond.name == 'CPP':
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| 181 | return False
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| 182 |
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| 183 | return stmt.else_body is not None
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| 184 |
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| 185 |
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| 186 | def IsUnusedVar(var_name: str) -> bool:
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| 187 | return var_name == '_' or var_name.startswith('unused')
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| 188 |
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| 189 |
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| 190 | def SkipAssignment(var_name: str) -> bool:
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| 191 | """
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| 192 | Skip at the top level:
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| 193 | _ = log
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| 194 | unused1 = log
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| 195 |
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| 196 | Always skip:
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| 197 | x, _ = mytuple # no second var
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| 198 | """
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| 199 | # __all__ should be excluded
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| 200 | return IsUnusedVar(var_name)
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