Class Expr

numpy/f2py/symbolic.py:157–787

Represents a Fortran expression as an op-data pair. Expr instances are hashable and sortable.

class Expr:
    """Represents a Fortran expression as an op-data pair.

    Expr instances are hashable and sortable.
    """

    @staticmethod
    def parse(s, language=Language.C):
        """Parse a Fortran expression to an Expr.
        """
        return fromstring(s, language=language)

    def __init__(self, op, data):
        assert isinstance(op, Op)

        # sanity checks
        if op is Op.INTEGER:
            # data is a 2-tuple of numeric object and a kind value
            # (default is 4)
            assert isinstance(data, tuple) and len(data) == 2
            assert isinstance(data[0], int)
            assert isinstance(data[1], (int, str)), data
        elif op is Op.REAL:
            # data is a 2-tuple of numeric object and a kind value
            # (default is 4)
            assert isinstance(data, tuple) and len(data) == 2
            assert isinstance(data[0], float)
            assert isinstance(data[1], (int, str)), data
        elif op is Op.COMPLEX:
            # data is a 2-tuple of constant expressions
            assert isinstance(data, tuple) and len(data) == 2
        elif op is Op.STRING:
            # data is a 2-tuple of quoted string and a kind value
            # (default is 1)
            assert isinstance(data, tuple) and len(data) == 2
            assert (isinstance(data[0], str)
                    and data[0][::len(data[0]) - 1] in ('""', "''", '@@'))
            assert isinstance(data[1], (int, str)), data
        elif op is Op.SYMBOL:
            # data is any hashable object
            assert hash(data) is not None
        elif op in (Op.ARRAY, Op.CONCAT):
            # data is a tuple of expressions
            assert isinstance(data, tuple)
            assert all(isinstance(item, Expr) for item in data), data
        elif op in (Op.TERMS, Op.FACTORS):
            # data is {<term|base>:<coeff|exponent>} where dict values
            # are nonzero Python integers
            assert isinstance(data, dict)
        elif op is Op.APPLY:
            # data is (<function>, <operands>, <kwoperands>) where
            # operands are Expr instances
            assert isinstance(data, tuple) and len(data) == 3
            # function is any hashable object
            assert hash(data[0]) is not None
            assert isinstance(data[1], tuple)
            assert isinstance(data[2], dict)
        elif op is Op.INDEXING: