push (lame)

main.py

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+import dataclasses
+import enum
+import logging
+import string
+
+from rich.logging import RichHandler
+
+logging.basicConfig(
+    level="INFO", format="%(message)s", datefmt="[%X]", handlers=[RichHandler()]
+)
+log = logging.getLogger(__name__)
+
+
+class TokenType(enum.Enum):
+    DIGIT = enum.auto()
+    OPERATOR = enum.auto()
+
+
+@dataclasses.dataclass
+class Token:
+    token_type: TokenType
+    literal: str
+    precedence: int
+    line: int
+    column: int
+
+    @classmethod
+    def from_char(cls, char: str, line: int, column: int) -> "Token | None":
+        if char.isdigit():
+            token_type = TokenType.DIGIT
+        elif char in "*/+-":
+            token_type = TokenType.OPERATOR
+        else:
+            return None
+
+        return cls(
+            token_type=token_type,
+            literal=char,
+            precedence=get_precedence(char),
+            line=line,
+            column=column,
+        )
+
+
+def get_precedence(char: str):
+    match char:
+        case "*" | "/":
+            return 2
+        case "+" | "-":
+            return 1
+        case _:
+            return 0
+
+
+def get_expr() -> str:
+    return "1 + 2\n * 6 / 2 * oarsetaortsn6 / 2"
+
+
+def goto_address(line, col) -> str:
+    return f"({line}:{col})"
+
+
+def tokenize_expr(expr: str) -> list[Token]:
+    stack = list()
+    line = 1
+    col = 0
+
+    for c in expr:
+        col += 1
+
+        if c in string.whitespace:
+            if c == "\n":
+                line += 1
+                col = 0
+            continue
+
+        current_token = Token.from_char(c, line, col)
+        if not current_token:
+            log.warning("Unexpected char %s: %s", goto_address(line, col), repr(c))
+            log.info("Ignoring char %s: %s", goto_address(line, col), repr(c))
+            continue
+
+        stack.append(current_token)
+
+    return stack
+
+
+def main() -> int:
+    expr = get_expr()
+    log.info(f"{expr=}")
+
+    expr_tokenized = tokenize_expr(expr)
+    log.info(f"{expr_tokenized=}")
+
+    rpn: list[Token] = []
+    stack: list[Token] = []
+
+    for token in expr_tokenized:
+        log.info(
+            f"{goto_address(token.line, token.column)}  {token.literal=}  {token.precedence=}"
+        )
+        if token.literal.isdigit():
+            rpn.append(token)
+        elif token.literal in "*/-+":
+            while stack and stack[-1].precedence >= token.precedence:
+                rpn.append(stack.pop())
+            stack.append(token)
+    while stack:
+        rpn.append(stack.pop())
+
+    log.info("RPN: %s", [c.literal for c in rpn])
+
+    return 0
+
+
+if __name__ == "__main__":
+    exit(main())