artifacts: add calculators/ — the 30 built calculators (5/variant) + machine-docs + git logs
This commit is contained in:
@@ -0,0 +1,50 @@
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"""
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AST evaluator for the calc expression language.
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evaluate(node) -> int | float
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Result type rule:
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- Integer arithmetic returns int.
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- Division (/) always uses true division; if the result is whole-valued
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(e.g. 4/2 == 2.0) it is coerced to int, otherwise returned as float.
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"""
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from calc.parser import Num, BinOp, Unary
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class EvalError(Exception):
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pass
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def evaluate(node):
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"""Walk an AST node and return an int or float result."""
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if isinstance(node, Num):
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return node.value
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if isinstance(node, Unary):
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val = evaluate(node.operand)
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if node.op == '-':
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return -val
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raise EvalError(f"Unknown unary operator: {node.op!r}")
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if isinstance(node, BinOp):
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left = evaluate(node.left)
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right = evaluate(node.right)
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if node.op == '+':
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result = left + right
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elif node.op == '-':
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result = left - right
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elif node.op == '*':
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result = left * right
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elif node.op == '/':
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if right == 0:
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raise EvalError("Division by zero")
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result = left / right
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else:
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raise EvalError(f"Unknown binary operator: {node.op!r}")
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# Coerce whole-valued floats to int so "4/2" prints as "2" not "2.0"
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if isinstance(result, float) and result.is_integer():
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return int(result)
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return result
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raise EvalError(f"Unknown AST node type: {type(node).__name__!r}")
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@@ -0,0 +1,58 @@
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class LexError(Exception):
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pass
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class Token:
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__slots__ = ('kind', 'value')
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def __init__(self, kind: str, value):
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self.kind = kind
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self.value = value
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def __repr__(self):
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return f'Token({self.kind!r}, {self.value!r})'
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def __eq__(self, other):
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if isinstance(other, Token):
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return self.kind == other.kind and self.value == other.value
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return NotImplemented
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_SINGLE_CHAR = {
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'+': 'PLUS',
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'-': 'MINUS',
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'*': 'STAR',
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'/': 'SLASH',
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'(': 'LPAREN',
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')': 'RPAREN',
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}
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def tokenize(src: str) -> list:
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tokens = []
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i = 0
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n = len(src)
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while i < n:
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c = src[i]
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if c in ' \t':
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i += 1
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elif c in _SINGLE_CHAR:
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tokens.append(Token(_SINGLE_CHAR[c], c))
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i += 1
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elif c.isdigit() or c == '.':
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start = i
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has_dot = False
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while i < n and (src[i].isdigit() or (src[i] == '.' and not has_dot)):
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if src[i] == '.':
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has_dot = True
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i += 1
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num_str = src[start:i]
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try:
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value = float(num_str) if has_dot else int(num_str)
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except ValueError:
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raise LexError(f"Invalid number {num_str!r} at position {start}")
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tokens.append(Token('NUMBER', value))
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else:
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raise LexError(f"Unexpected character {c!r} at position {i}")
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tokens.append(Token('EOF', None))
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return tokens
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@@ -0,0 +1,149 @@
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"""
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Recursive-descent parser for the calc expression grammar.
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Grammar:
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expr = term ( ('+' | '-') term )*
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term = unary ( ('*' | '/') unary )*
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unary = '-' unary | primary
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primary = NUMBER | '(' expr ')'
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AST node shapes (stable contract for the evaluator):
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Num(value) — numeric literal; .value is int or float
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BinOp(op, left, right) — binary operation; .op is '+', '-', '*', or '/'
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Unary(op, operand) — unary prefix; .op is '-'
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"""
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class ParseError(Exception):
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pass
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# ---------------------------------------------------------------------------
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# AST nodes
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# ---------------------------------------------------------------------------
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class Num:
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__slots__ = ('value',)
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def __init__(self, value):
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self.value = value
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def __repr__(self):
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return f'Num({self.value!r})'
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def __eq__(self, other):
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return isinstance(other, Num) and self.value == other.value
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class BinOp:
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__slots__ = ('op', 'left', 'right')
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def __init__(self, op: str, left, right):
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self.op = op
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self.left = left
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self.right = right
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def __repr__(self):
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return f'BinOp({self.op!r}, {self.left!r}, {self.right!r})'
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def __eq__(self, other):
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return (isinstance(other, BinOp)
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and self.op == other.op
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and self.left == other.left
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and self.right == other.right)
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class Unary:
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__slots__ = ('op', 'operand')
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def __init__(self, op: str, operand):
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self.op = op
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self.operand = operand
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def __repr__(self):
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return f'Unary({self.op!r}, {self.operand!r})'
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def __eq__(self, other):
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return (isinstance(other, Unary)
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and self.op == other.op
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and self.operand == other.operand)
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# ---------------------------------------------------------------------------
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# Parser
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# ---------------------------------------------------------------------------
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class _Parser:
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def __init__(self, tokens):
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self._tokens = tokens
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self._pos = 0
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def _peek(self):
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return self._tokens[self._pos]
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def _advance(self):
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tok = self._tokens[self._pos]
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self._pos += 1
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return tok
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def _expect(self, kind):
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tok = self._peek()
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if tok.kind != kind:
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raise ParseError(
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f"Expected {kind}, got {tok.kind!r} ({tok.value!r})"
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)
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return self._advance()
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# expr = term ( ('+' | '-') term )*
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def _expr(self):
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node = self._term()
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while self._peek().kind in ('PLUS', 'MINUS'):
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op = self._advance().value
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node = BinOp(op, node, self._term())
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return node
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# term = unary ( ('*' | '/') unary )*
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def _term(self):
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node = self._unary()
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while self._peek().kind in ('STAR', 'SLASH'):
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op = self._advance().value
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node = BinOp(op, node, self._unary())
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return node
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# unary = '-' unary | primary
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def _unary(self):
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if self._peek().kind == 'MINUS':
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self._advance()
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return Unary('-', self._unary())
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return self._primary()
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# primary = NUMBER | '(' expr ')'
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def _primary(self):
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tok = self._peek()
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if tok.kind == 'NUMBER':
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self._advance()
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return Num(tok.value)
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if tok.kind == 'LPAREN':
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self._advance()
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node = self._expr()
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self._expect('RPAREN')
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return node
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if tok.kind == 'EOF':
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raise ParseError("Unexpected end of input")
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raise ParseError(f"Unexpected token {tok.kind!r} ({tok.value!r})")
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def parse(self):
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if self._peek().kind == 'EOF':
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raise ParseError("Empty input")
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node = self._expr()
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if self._peek().kind != 'EOF':
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tok = self._peek()
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raise ParseError(
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f"Unexpected token after expression: {tok.kind!r} ({tok.value!r})"
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)
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return node
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def parse(tokens) -> object:
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"""Parse a token list produced by `calc.lexer.tokenize` into an AST."""
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return _Parser(tokens).parse()
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@@ -0,0 +1,131 @@
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import subprocess
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import sys
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import unittest
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from calc.evaluator import EvalError, evaluate
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from calc.lexer import tokenize
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from calc.parser import parse
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def calc(s):
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return evaluate(parse(tokenize(s)))
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class TestArithmetic(unittest.TestCase):
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"""D1 — arithmetic operators, precedence, parens, unary minus."""
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def test_addition(self):
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self.assertEqual(calc("1+2"), 3)
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def test_subtraction(self):
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self.assertEqual(calc("5-3"), 2)
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def test_multiplication(self):
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self.assertEqual(calc("3*4"), 12)
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def test_precedence_mul_over_add(self):
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self.assertEqual(calc("2+3*4"), 14)
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def test_precedence_paren(self):
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self.assertEqual(calc("(2+3)*4"), 20)
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def test_left_assoc_subtraction(self):
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self.assertEqual(calc("8-3-2"), 3)
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def test_unary_minus_simple(self):
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self.assertEqual(calc("-2+5"), 3)
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def test_unary_minus_in_mul(self):
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self.assertEqual(calc("2*-3"), -6)
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def test_negative_literal(self):
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self.assertEqual(calc("-5"), -5)
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def test_nested_parens(self):
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self.assertEqual(calc("((2+3))*4"), 20)
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class TestDivision(unittest.TestCase):
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"""D2 — true division and EvalError on divide-by-zero."""
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def test_true_division(self):
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self.assertEqual(calc("7/2"), 3.5)
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def test_division_by_zero_raises_eval_error(self):
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with self.assertRaises(EvalError):
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calc("1/0")
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def test_division_by_zero_no_bare_exception(self):
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"""ZeroDivisionError must not escape the API."""
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try:
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calc("1/0")
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except EvalError:
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pass
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except ZeroDivisionError:
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self.fail("ZeroDivisionError escaped the evaluate() API")
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def test_division_chain(self):
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self.assertEqual(calc("8/4/2"), 1)
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class TestResultType(unittest.TestCase):
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"""D3 — result type: whole-valued → int, non-whole → float."""
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def test_whole_division_returns_int(self):
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result = calc("4/2")
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self.assertEqual(result, 2)
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self.assertIsInstance(result, int)
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def test_non_whole_division_returns_float(self):
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result = calc("7/2")
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self.assertEqual(result, 3.5)
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self.assertIsInstance(result, float)
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def test_integer_arithmetic_returns_int(self):
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result = calc("2+3*4")
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self.assertEqual(result, 14)
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self.assertIsInstance(result, int)
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def test_whole_str_no_dot(self):
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self.assertEqual(str(calc("4/2")), "2")
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def test_float_str_has_dot(self):
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self.assertEqual(str(calc("7/2")), "3.5")
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class TestCLI(unittest.TestCase):
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"""D4 — CLI behaviour."""
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def _run(self, expr):
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return subprocess.run(
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[sys.executable, 'calc.py', expr],
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capture_output=True, text=True,
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)
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def test_valid_simple(self):
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r = self._run("2+3*4")
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self.assertEqual(r.returncode, 0)
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self.assertEqual(r.stdout.strip(), "14")
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self.assertEqual(r.stderr, "")
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def test_valid_parens(self):
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r = self._run("(2+3)*4")
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self.assertEqual(r.returncode, 0)
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self.assertEqual(r.stdout.strip(), "20")
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def test_invalid_exits_nonzero(self):
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r = self._run("1 +")
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self.assertNotEqual(r.returncode, 0)
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def test_invalid_error_to_stderr(self):
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r = self._run("1 +")
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self.assertEqual(r.stdout, "")
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self.assertTrue(r.stderr.strip(), "expected error message on stderr")
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def test_invalid_no_traceback(self):
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r = self._run("1 +")
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self.assertNotIn("Traceback", r.stderr)
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if __name__ == '__main__':
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unittest.main()
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@@ -0,0 +1,118 @@
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import unittest
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from calc.lexer import tokenize, Token, LexError
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class TestNumbers(unittest.TestCase):
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def test_integer(self):
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result = tokenize("42")
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self.assertEqual(result, [Token('NUMBER', 42), Token('EOF', None)])
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self.assertIsInstance(result[0].value, int)
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def test_float_standard(self):
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result = tokenize("3.14")
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self.assertEqual(result[0].kind, 'NUMBER')
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self.assertAlmostEqual(result[0].value, 3.14)
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self.assertIsInstance(result[0].value, float)
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def test_float_leading_dot(self):
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result = tokenize(".5")
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self.assertEqual(result[0].kind, 'NUMBER')
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self.assertAlmostEqual(result[0].value, 0.5)
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self.assertIsInstance(result[0].value, float)
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def test_float_trailing_dot(self):
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result = tokenize("10.")
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self.assertEqual(result[0].kind, 'NUMBER')
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self.assertAlmostEqual(result[0].value, 10.0)
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self.assertIsInstance(result[0].value, float)
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def test_eof_is_last(self):
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result = tokenize("42")
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self.assertEqual(result[-1].kind, 'EOF')
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class TestOperatorsAndParens(unittest.TestCase):
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def _kinds(self, src):
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return [t.kind for t in tokenize(src)]
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def test_plus(self):
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self.assertEqual(self._kinds("+"), ['PLUS', 'EOF'])
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def test_minus(self):
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self.assertEqual(self._kinds("-"), ['MINUS', 'EOF'])
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def test_star(self):
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self.assertEqual(self._kinds("*"), ['STAR', 'EOF'])
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def test_slash(self):
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self.assertEqual(self._kinds("/"), ['SLASH', 'EOF'])
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def test_lparen(self):
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self.assertEqual(self._kinds("("), ['LPAREN', 'EOF'])
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def test_rparen(self):
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self.assertEqual(self._kinds(")"), ['RPAREN', 'EOF'])
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def test_expression_1_plus_2_star_3(self):
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self.assertEqual(
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self._kinds("1+2*3"),
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['NUMBER', 'PLUS', 'NUMBER', 'STAR', 'NUMBER', 'EOF'],
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||||
)
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||||
|
||||
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||||
class TestWhitespaceAndErrors(unittest.TestCase):
|
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def _kinds(self, src):
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return [t.kind for t in tokenize(src)]
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||||
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def test_whitespace_around_tokens(self):
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result = tokenize(" 12 + 3 ")
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self.assertEqual(
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[t.kind for t in result],
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||||
['NUMBER', 'PLUS', 'NUMBER', 'EOF'],
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||||
)
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nums = [t.value for t in result if t.kind == 'NUMBER']
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self.assertEqual(nums, [12, 3])
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||||
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def test_complex_expression(self):
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result = tokenize("3.5*(1-2)")
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self.assertEqual(
|
||||
[t.kind for t in result],
|
||||
['NUMBER', 'STAR', 'LPAREN', 'NUMBER', 'MINUS', 'NUMBER', 'RPAREN', 'EOF'],
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||||
)
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||||
self.assertAlmostEqual(result[0].value, 3.5)
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self.assertEqual(result[3].value, 1)
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self.assertEqual(result[5].value, 2)
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||||
|
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def test_lex_error_at_sign(self):
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||||
with self.assertRaises(LexError):
|
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tokenize("1 @ 2")
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||||
|
||||
def test_lex_error_dollar(self):
|
||||
with self.assertRaises(LexError):
|
||||
tokenize("$")
|
||||
|
||||
def test_lex_error_letter(self):
|
||||
with self.assertRaises(LexError):
|
||||
tokenize("x + 1")
|
||||
|
||||
def test_lex_error_message_contains_char(self):
|
||||
with self.assertRaises(LexError) as ctx:
|
||||
tokenize("1 @ 2")
|
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self.assertIn('@', str(ctx.exception))
|
||||
|
||||
def test_lex_error_message_contains_position(self):
|
||||
with self.assertRaises(LexError) as ctx:
|
||||
tokenize("1 @ 2")
|
||||
# '@' is at position 2
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||||
self.assertIn('2', str(ctx.exception))
|
||||
|
||||
def test_tab_whitespace(self):
|
||||
result = tokenize("1\t+\t2")
|
||||
self.assertEqual(
|
||||
[t.kind for t in result],
|
||||
['NUMBER', 'PLUS', 'NUMBER', 'EOF'],
|
||||
)
|
||||
|
||||
|
||||
if __name__ == '__main__':
|
||||
unittest.main()
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||||
@@ -0,0 +1,128 @@
|
||||
import unittest
|
||||
|
||||
from calc.lexer import tokenize
|
||||
from calc.parser import parse, ParseError, Num, BinOp, Unary
|
||||
|
||||
|
||||
def p(src):
|
||||
return parse(tokenize(src))
|
||||
|
||||
|
||||
class TestPrecedence(unittest.TestCase):
|
||||
"""D1 — * and / bind tighter than + and -."""
|
||||
|
||||
def test_add_then_mul(self):
|
||||
# 1+2*3 → BinOp('+', Num(1), BinOp('*', Num(2), Num(3)))
|
||||
self.assertEqual(p('1+2*3'), BinOp('+', Num(1), BinOp('*', Num(2), Num(3))))
|
||||
|
||||
def test_mul_then_add(self):
|
||||
# 2*3+4 → BinOp('+', BinOp('*', Num(2), Num(3)), Num(4))
|
||||
self.assertEqual(p('2*3+4'), BinOp('+', BinOp('*', Num(2), Num(3)), Num(4)))
|
||||
|
||||
def test_add_then_div(self):
|
||||
# 1+6/2 → BinOp('+', Num(1), BinOp('/', Num(6), Num(2)))
|
||||
self.assertEqual(p('1+6/2'), BinOp('+', Num(1), BinOp('/', Num(6), Num(2))))
|
||||
|
||||
def test_sub_then_mul(self):
|
||||
# 10-2*3 → BinOp('-', Num(10), BinOp('*', Num(2), Num(3)))
|
||||
self.assertEqual(p('10-2*3'), BinOp('-', Num(10), BinOp('*', Num(2), Num(3))))
|
||||
|
||||
|
||||
class TestLeftAssociativity(unittest.TestCase):
|
||||
"""D2 — same-precedence operators associate left."""
|
||||
|
||||
def test_sub_sub(self):
|
||||
# 8-3-2 → BinOp('-', BinOp('-', Num(8), Num(3)), Num(2))
|
||||
self.assertEqual(p('8-3-2'), BinOp('-', BinOp('-', Num(8), Num(3)), Num(2)))
|
||||
|
||||
def test_div_div(self):
|
||||
# 8/4/2 → BinOp('/', BinOp('/', Num(8), Num(4)), Num(2))
|
||||
self.assertEqual(p('8/4/2'), BinOp('/', BinOp('/', Num(8), Num(4)), Num(2)))
|
||||
|
||||
def test_add_add(self):
|
||||
# 1+2+3 → BinOp('+', BinOp('+', Num(1), Num(2)), Num(3))
|
||||
self.assertEqual(p('1+2+3'), BinOp('+', BinOp('+', Num(1), Num(2)), Num(3)))
|
||||
|
||||
def test_mul_mul(self):
|
||||
# 2*3*4 → BinOp('*', BinOp('*', Num(2), Num(3)), Num(4))
|
||||
self.assertEqual(p('2*3*4'), BinOp('*', BinOp('*', Num(2), Num(3)), Num(4)))
|
||||
|
||||
|
||||
class TestParentheses(unittest.TestCase):
|
||||
"""D3 — parens override precedence."""
|
||||
|
||||
def test_parens_override_mul(self):
|
||||
# (1+2)*3 → BinOp('*', BinOp('+', Num(1), Num(2)), Num(3))
|
||||
self.assertEqual(p('(1+2)*3'), BinOp('*', BinOp('+', Num(1), Num(2)), Num(3)))
|
||||
|
||||
def test_nested_parens(self):
|
||||
# (1+(2*3)) → BinOp('+', Num(1), BinOp('*', Num(2), Num(3)))
|
||||
self.assertEqual(p('(1+(2*3))'), BinOp('+', Num(1), BinOp('*', Num(2), Num(3))))
|
||||
|
||||
def test_parens_on_right(self):
|
||||
# 3*(1+2) → BinOp('*', Num(3), BinOp('+', Num(1), Num(2)))
|
||||
self.assertEqual(p('3*(1+2)'), BinOp('*', Num(3), BinOp('+', Num(1), Num(2))))
|
||||
|
||||
def test_double_parens(self):
|
||||
# ((7)) → Num(7)
|
||||
self.assertEqual(p('((7))'), Num(7))
|
||||
|
||||
|
||||
class TestUnaryMinus(unittest.TestCase):
|
||||
"""D4 — leading and nested unary minus."""
|
||||
|
||||
def test_simple_unary(self):
|
||||
# -5 → Unary('-', Num(5))
|
||||
self.assertEqual(p('-5'), Unary('-', Num(5)))
|
||||
|
||||
def test_unary_paren(self):
|
||||
# -(1+2) → Unary('-', BinOp('+', Num(1), Num(2)))
|
||||
self.assertEqual(p('-(1+2)'), Unary('-', BinOp('+', Num(1), Num(2))))
|
||||
|
||||
def test_unary_in_binop(self):
|
||||
# 3 * -2 → BinOp('*', Num(3), Unary('-', Num(2)))
|
||||
self.assertEqual(p('3 * -2'), BinOp('*', Num(3), Unary('-', Num(2))))
|
||||
|
||||
def test_double_unary(self):
|
||||
# --5 → Unary('-', Unary('-', Num(5)))
|
||||
self.assertEqual(p('--5'), Unary('-', Unary('-', Num(5))))
|
||||
|
||||
def test_unary_in_add(self):
|
||||
# 1 + -2 → BinOp('+', Num(1), Unary('-', Num(2)))
|
||||
self.assertEqual(p('1 + -2'), BinOp('+', Num(1), Unary('-', Num(2))))
|
||||
|
||||
|
||||
class TestErrors(unittest.TestCase):
|
||||
"""D5 — malformed input raises ParseError."""
|
||||
|
||||
def test_trailing_op(self):
|
||||
with self.assertRaises(ParseError):
|
||||
p('1 +')
|
||||
|
||||
def test_unclosed_paren(self):
|
||||
with self.assertRaises(ParseError):
|
||||
p('(1')
|
||||
|
||||
def test_two_numbers(self):
|
||||
with self.assertRaises(ParseError):
|
||||
p('1 2')
|
||||
|
||||
def test_close_before_open(self):
|
||||
with self.assertRaises(ParseError):
|
||||
p(')(')
|
||||
|
||||
def test_empty_string(self):
|
||||
with self.assertRaises(ParseError):
|
||||
p('')
|
||||
|
||||
def test_only_operator(self):
|
||||
with self.assertRaises(ParseError):
|
||||
p('*')
|
||||
|
||||
def test_double_op(self):
|
||||
with self.assertRaises(ParseError):
|
||||
p('1 + + 2')
|
||||
|
||||
|
||||
if __name__ == '__main__':
|
||||
unittest.main()
|
||||
Reference in New Issue
Block a user