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70 lines
2.0 KiB
70 lines
2.0 KiB
import os
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import tempfile
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from pathlib import Path
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import sympy
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from sympy.testing.pytest import raises
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from sympy.parsing.latex.lark import LarkLaTeXParser, TransformToSymPyExpr, parse_latex_lark
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from sympy.external import import_module
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lark = import_module("lark")
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# disable tests if lark is not present
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disabled = lark is None
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grammar_file = os.path.join(os.path.dirname(__file__), "../latex/lark/grammar/latex.lark")
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modification1 = """
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%override DIV_SYMBOL: DIV
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%override MUL_SYMBOL: MUL | CMD_TIMES
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"""
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modification2 = r"""
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%override number: /\d+(,\d*)?/
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"""
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def init_custom_parser(modification, transformer=None):
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latex_grammar = Path(grammar_file).read_text(encoding="utf-8")
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latex_grammar += modification
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with tempfile.NamedTemporaryFile() as f:
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f.write(bytes(latex_grammar, encoding="utf8"))
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f.flush()
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parser = LarkLaTeXParser(grammar_file=f.name, transformer=transformer)
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return parser
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def test_custom1():
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# Removes the parser's ability to understand \cdot and \div.
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parser = init_custom_parser(modification1)
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with raises(lark.exceptions.UnexpectedCharacters):
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parser.doparse(r"a \cdot b")
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parser.doparse(r"x \div y")
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class CustomTransformer(TransformToSymPyExpr):
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def number(self, tokens):
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if "," in tokens[0]:
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# The Float constructor expects a dot as the decimal separator
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return sympy.core.numbers.Float(tokens[0].replace(",", "."))
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else:
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return sympy.core.numbers.Integer(tokens[0])
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def test_custom2():
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# Makes the parser parse commas as the decimal separator instead of dots
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parser = init_custom_parser(modification2, CustomTransformer)
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with raises(lark.exceptions.UnexpectedCharacters):
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# Asserting that the default parser cannot parse numbers which have commas as
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# the decimal separator
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parse_latex_lark("100,1")
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parse_latex_lark("0,009")
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parser.doparse("100,1")
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parser.doparse("0,009")
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parser.doparse("2,71828")
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parser.doparse("3,14159")
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