mirror of
https://github.com/searxng/searxng
synced 2024-01-01 19:24:07 +01:00
59 lines
1.2 KiB
Python
59 lines
1.2 KiB
Python
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# SPDX-License-Identifier: AGPL-3.0-or-later
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"""Standalone script to actually calculate mathematical expressions using ast
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This is not a module, the SearXNG modules are not available here
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"""
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import ast
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import sys
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import operator
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from typing import Callable
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operators: dict[type, Callable] = {
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ast.Add: operator.add,
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ast.Sub: operator.sub,
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ast.Mult: operator.mul,
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ast.Div: operator.truediv,
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ast.Pow: operator.pow,
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ast.BitXor: operator.xor,
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ast.USub: operator.neg,
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}
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def _eval_expr(expr):
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"""
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>>> _eval_expr('2^6')
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4
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>>> _eval_expr('2**6')
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64
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>>> _eval_expr('1 + 2*3**(4^5) / (6 + -7)')
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-5.0
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"""
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try:
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return _eval(ast.parse(expr, mode='eval').body)
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except ZeroDivisionError:
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# This is undefined
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return ""
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def _eval(node):
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if isinstance(node, ast.Constant) and isinstance(node.value, (int, float)):
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return node.value
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if isinstance(node, ast.BinOp):
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return operators[type(node.op)](_eval(node.left), _eval(node.right))
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if isinstance(node, ast.UnaryOp):
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return operators[type(node.op)](_eval(node.operand))
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raise TypeError(node)
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def main():
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print(_eval_expr(sys.argv[1]), end="")
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if __name__ == "__main__":
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main()
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