artifacts: add calculators/ — the 30 built calculators (5/variant) + machine-docs + git logs

calculators/builder-adversary-stateless/run-04/calc/parser.py

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+from dataclasses import dataclass
+from typing import Union
+
+
+class ParseError(Exception):
+    pass
+
+
+@dataclass
+class Num:
+    value: Union[int, float]
+
+    def __repr__(self):
+        return f"Num({self.value!r})"
+
+
+@dataclass
+class BinOp:
+    op: str
+    left: object
+    right: object
+
+    def __repr__(self):
+        return f"BinOp({self.op!r}, {self.left!r}, {self.right!r})"
+
+
+@dataclass
+class Unary:
+    op: str
+    operand: object
+
+    def __repr__(self):
+        return f"Unary({self.op!r}, {self.operand!r})"
+
+
+def parse(tokens: list):
+    """Parse a token list into an AST.
+
+    Grammar:
+        expr    → term   (('+' | '-') term)*
+        term    → unary  (('*' | '/') unary)*
+        unary   → '-' unary | primary
+        primary → NUMBER | '(' expr ')'
+
+    Returns the root Node.  Raises ParseError on malformed input.
+    """
+    pos = 0
+
+    def peek():
+        return tokens[pos]
+
+    def consume(kind=None):
+        nonlocal pos
+        tok = tokens[pos]
+        if kind and tok.kind != kind:
+            raise ParseError(f"expected {kind}, got {tok.kind!r}")
+        pos += 1
+        return tok
+
+    def expr():
+        left = term()
+        while peek().kind in ('PLUS', 'MINUS'):
+            op = consume().kind
+            right = term()
+            left = BinOp(op, left, right)
+        return left
+
+    def term():
+        left = unary()
+        while peek().kind in ('STAR', 'SLASH'):
+            op = consume().kind
+            right = unary()
+            left = BinOp(op, left, right)
+        return left
+
+    def unary():
+        if peek().kind == 'MINUS':
+            op = consume().kind
+            operand = unary()
+            return Unary(op, operand)
+        return primary()
+
+    def primary():
+        tok = peek()
+        if tok.kind == 'NUMBER':
+            consume()
+            return Num(tok.value)
+        if tok.kind == 'LPAREN':
+            consume()
+            node = expr()
+            if peek().kind != 'RPAREN':
+                raise ParseError(f"expected ')', got {peek().kind!r}")
+            consume()
+            return node
+        raise ParseError(f"unexpected token {tok.kind!r}")
+
+    node = expr()
+    if peek().kind != 'EOF':
+        raise ParseError(f"unexpected token {peek().kind!r} after expression")
+    return node