37 lines
926 B
Python
37 lines
926 B
Python
"""Command-line interface: python calc.py "<expression>"
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Result printing rule:
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- If the result is a whole number (e.g. 2.0), print as int (e.g. "2").
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- Otherwise print as float (e.g. "3.5").
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"""
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import sys
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from calc.lexer import tokenize, LexError
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from calc.parser import parse, ParseError
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from calc.evaluator import evaluate, EvalError
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def _format(value) -> str:
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if isinstance(value, float) and value.is_integer():
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return str(int(value))
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return str(value)
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def main():
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if len(sys.argv) != 2:
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print(f"usage: {sys.argv[0]} <expression>", file=sys.stderr)
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sys.exit(1)
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expr = sys.argv[1]
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try:
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tokens = tokenize(expr)
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ast = parse(tokens)
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result = evaluate(ast)
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print(_format(result))
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except (LexError, ParseError, EvalError) as exc:
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print(f"error: {exc}", file=sys.stderr)
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sys.exit(1)
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if __name__ == "__main__":
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main()
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