nodeslicer/infra/prusaslicer_profiles/parser.py

from __future__ import annotations
import operator
import re
from typing import Any

TOKENS = [
    ('OP', r'==|!=|<=|>=|=~|!~|&&|\|\||[()\[\]!><]'),
    ('REGEX', r'/((?:\\/|[^/])*)/'),
    ('STRING', r'"(?:[^"\\]|\\.)*"|\'(?:[^\'\\]|\\.)*\''),
    ('NUMBER', r'\d+(?:\.\d+)?'),
    ('IDENT', r'[a-zA-Z_]\w*'),
]
TOKEN_RE = re.compile('|'.join(f'(?P<{name}>{pattern})' for name, pattern in TOKENS))

_OPS = {
    '==': (str, operator.eq),
    '!=': (str, operator.ne),
    '<':  (float, operator.lt),
    '>':  (float, operator.gt),
    '<=': (float, operator.le),
    '>=': (float, operator.ge),
}

def _tokenize(text: str) -> list[tuple[str, Any]]:
    tokens: list[tuple[str, Any]] = []
    for m in TOKEN_RE.finditer(text):
        kind: str = m.lastgroup if m.lastgroup else ""
        val = m.group(kind)
        if kind == 'OP':
            if val == '&&': tokens.append(('OP', 'and'))
            elif val == '||': tokens.append(('OP', 'or'))
            elif val in ('(', ')', '[', ']'): tokens.append((val, val))
            else: tokens.append(('OP', val))
        elif kind == 'REGEX':
            tokens.append(('REGEX', re.compile(val[1:-1])))
        elif kind == 'STRING':
            tokens.append(('LIT', val[1:-1]))
        elif kind == 'NUMBER':
            tokens.append(('LIT', val))
        elif kind == 'IDENT':
            if val == 'and': tokens.append(('OP', 'and'))
            elif val == 'or': tokens.append(('OP', 'or'))
            else: tokens.append(('IDENT', val))
    return tokens

class ExprNode:
    """Represents an expression node in the AST."""
    def __init__(self, node: tuple[Any, ...]) -> None:
        self.node = node

    def eval(self, context: dict[str, Any]) -> Any:
        return self._eval_node(self.node, context)

    @staticmethod
    def _eval_node(node: tuple[Any, ...], context: dict[str, Any]) -> Any:
        ntype = node[0]
        if ntype == 'lit':
            return node[1]
        if ntype == 'var':
            return context.get(node[1], '0')
        if ntype == 'index':
            val = str(context.get(node[1], '0'))
            parts = val.split(',')
            idx = node[2]
            return parts[idx].strip() if idx < len(parts) else '0'
        if ntype == 'unary':
            cval = ExprNode._eval_node(node[2], context)
            try:
                return not float(cval)
            except (ValueError, TypeError):
                return not bool(cval)
        if ntype == 'bin':
            op, left, right = node[1], node[2], node[3]
            if op == 'and':
                lv = ExprNode._eval_node(left, context)
                if not lv or lv == '0': return False
                return ExprNode._eval_node(right, context)
            if op == 'or':
                lv = ExprNode._eval_node(left, context)
                if lv and lv != '0': return True
                return ExprNode._eval_node(right, context)
            lv = ExprNode._eval_node(left, context)
            rv = ExprNode._eval_node(right, context)
            if op in _OPS:
                caster, func = _OPS[op]
                try:
                    return func(caster(lv), caster(rv))
                except (ValueError, TypeError):
                    return func(str(lv), str(rv))
            if op == '=~':
                return rv.search(str(lv)) is not None
            if op == '!~':
                return rv.search(str(lv)) is None
        return '0'

class Parser:
    """Recursive descent parser for PrusaSlicer expressions."""
    def __init__(self, text: str) -> None:
        self.tokens = _tokenize(text)
        self.pos = 0

    def parse(self) -> ExprNode:
        node = self._parse_or()
        if self.pos < len(self.tokens):
            raise SyntaxError(f'Trailing tokens: {self.tokens[self.pos:]}')
        return ExprNode(node)

    def _peek(self) -> tuple[str, Any] | None:
        return self.tokens[self.pos] if self.pos < len(self.tokens) else None

    def _advance(self) -> tuple[str, Any]:
        tok = self.tokens[self.pos]
        self.pos += 1
        return tok

    def _parse_or(self) -> tuple[Any, ...]:
        left = self._parse_and()
        while (tok := self._peek()) and tok == ('OP', 'or'):
            self._advance()
            left = ('bin', 'or', left, self._parse_and())
        return left

    def _parse_and(self) -> tuple[Any, ...]:
        left = self._parse_not()
        while (tok := self._peek()) and tok == ('OP', 'and'):
            self._advance()
            left = ('bin', 'and', left, self._parse_not())
        return left

    def _parse_not(self) -> tuple[Any, ...]:
        if (tok := self._peek()) and tok == ('OP', '!'):
            self._advance()
            return ('unary', '!', self._parse_not())
        return self._parse_comp()

    def _parse_comp(self) -> tuple[Any, ...]:
        left = self._parse_atom()
        if (tok := self._peek()) and tok[0] == 'OP' and tok[1] in ('==', '!=', '<', '>', '<=', '>=', '=~', '!~'):
            op = self._advance()[1]
            left = ('bin', op, left, self._parse_atom())
        return left

    def _parse_atom(self) -> tuple[Any, ...]:
        tok = self._advance()
        ttype, val = tok
        if ttype in ('LIT', 'REGEX'):
            return ('lit', val)
        if ttype == 'IDENT':
            if self._peek() == ('[', '['):
                self._advance()
                idx_tok = self._advance()
                if self._advance() != (']', ']'): raise SyntaxError('Expected ]')
                return ('index', val, int(idx_tok[1]))
            return ('var', val)
        if ttype == '(':
            node = self._parse_or()
            if self._advance() != (')', ')'): raise SyntaxError('Expected )')
            return node
        raise SyntaxError(f'Unexpected token: {tok}')