Added command line calculator script

Author: VarunArora24

scripts/command_line_calculator.py

@@ -0,0 +1,175 @@
+"""
+Expression Evaluator
+--------------------
+A Python module that evaluates arithmetic and bitwise expressions.
+
+Supports:
+    +  -  *  /  **  <<  >>  &  |  ^  ( )
+
+
+
+Usage:
+    >>> from evaluator import evaluate
+    >>> evaluate("2 + 3 * 4")
+    14
+    >>> evaluate("(2 + 3) * 4")
+    20
+    >>> evaluate("2 ** 8")
+    256
+    >>> evaluate("10 | 6")
+    14
+    >>> evaluate("10 & 6")
+    2
+    >>> evaluate("(10 | 6) ^ 5")
+    9
+    >>> evaluate("10 / 4")
+    2.5
+"""
+
+import re
+
+def evaluate(expr: str):
+    """
+    Evaluate an arithmetic/bitwise expression string and return result.
+
+    Args:
+        expr (str): Expression to evaluate
+
+    Returns:
+        int | float: The computed result, automatically casted.
+
+    Examples:
+        >>> evaluate("2 + 3 * 4")
+        14
+        >>> evaluate("2 ** 10")
+        1024
+        >>> evaluate("10 / 4")
+        2.5
+        >>> evaluate("(10 | 6) ^ 5")
+        9
+    """
+
+    # --- Tokenization ---
+    tokens = re.findall(r'\d+\.\d+|\d+|\*\*|<<|>>|[&|^+\-*/()]', expr.replace(" ", ""))
+
+    # --- Handle unary minus (e.g., -5 + 3) and minus in starting ---
+    if tokens and tokens[0] == "-":
+        tokens.insert(0, "0")
+
+    def clean(lst):
+        return [x for x in lst if x is not None]
+
+    def solve_power(z):
+        while "**" in z:
+            i = z.index("**")
+            z[i - 1] = float(z[i - 1]) ** float(z[i + 1])
+            z[i:i + 2] = [None, None]
+            z = clean(z)
+        return z
+
+    def solve_div(z):
+        while "/" in z:
+            i = z.index("/")
+            z[i - 1] = float(z[i - 1]) / float(z[i + 1])
+            z[i:i + 2] = [None, None]
+            z = clean(z)
+        return z
+
+    def solve_mul(z):
+        while "*" in z:
+            i = z.index("*")
+            z[i - 1] = float(z[i - 1]) * float(z[i + 1])
+            z[i:i + 2] = [None, None]
+            z = clean(z)
+        return z
+
+    def solve_minus(z):
+        while "-" in z:
+            i = z.index("-")
+            z[i] = "+"
+            z[i + 1] = -1 * float(z[i + 1])
+        return z
+
+    def solve_add(z):
+        while "+" in z:
+            i = z.index("+")
+            z[i - 1] = float(z[i - 1]) + float(z[i + 1])
+            z[i:i + 2] = [None, None]
+            z = clean(z)
+        return z
+
+    def solve_lshift(z):
+        while "<<" in z:
+            i = z.index("<<")
+            z[i - 1] = int(float(z[i - 1])) << int(float(z[i + 1]))
+            z[i:i + 2] = [None, None]
+            z = clean(z)
+        return z
+
+    def solve_rshift(z):
+        while ">>" in z:
+            i = z.index(">>")
+            z[i - 1] = int(float(z[i - 1])) >> int(float(z[i + 1]))
+            z[i:i + 2] = [None, None]
+            z = clean(z)
+        return z
+
+    def solve_and(z):
+        while "&" in z:
+            i = z.index("&")
+            z[i - 1] = int(float(z[i - 1])) & int(float(z[i + 1]))
+            z[i:i + 2] = [None, None]
+            z = clean(z)
+        return z
+
+    def solve_xor(z):
+        while "^" in z:
+            i = z.index("^")
+            z[i - 1] = int(float(z[i - 1])) ^ int(float(z[i + 1]))
+            z[i:i + 2] = [None, None]
+            z = clean(z)
+        return z
+
+    def solve_or(z):
+        while "|" in z:
+            i = z.index("|")
+            z[i - 1] = int(float(z[i - 1])) | int(float(z[i + 1]))
+            z[i:i + 2] = [None, None]
+            z = clean(z)
+        return z
+
+    def solve_parentheses(z):
+        while "(" in z:
+            close = z.index(")")
+            open_ = max(i for i, v in enumerate(z[:close]) if v == "(")
+            inner = z[open_ + 1:close]
+            result = evaluate(" ".join(map(str, inner)))
+            z = z[:open_] + [str(result)] + z[close + 1:]
+        return z
+
+    tokens = solve_parentheses(tokens)
+
+    # Precedence order
+    for func in [solve_power, solve_div, solve_mul, solve_minus, solve_add,
+                 solve_lshift, solve_rshift, solve_and, solve_xor, solve_or]:
+        tokens = func(tokens)
+
+    result = tokens[0]
+
+    # Return as int if it’s cleanly integer-valued
+    if isinstance(result, (int, float)):
+        if abs(result - int(result)) < 1e-9:
+            return int(result)
+        return float(result)
+
+    # If it's a string (edge-case), convert safely
+    try:
+        f = float(result)
+        return int(f) if f.is_integer() else f
+    except ValueError:
+        raise ValueError("Invalid expression or unsupported syntax.")
+    
+
+if __name__ == "__main__":
+    import doctest
+    doctest.testmod(verbose=True)