def format()

in xray-setup/psycopg2/sql.py [0:0]

• 27 lines of code
• 10 McCabe index (conditional complexity)

    def format(self, *args, **kwargs):
        """
        Merge `Composable` objects into a template.

        :param `Composable` args: parameters to replace to numbered
            (``{0}``, ``{1}``) or auto-numbered (``{}``) placeholders
        :param `Composable` kwargs: parameters to replace to named (``{name}``)
            placeholders
        :return: the union of the `!SQL` string with placeholders replaced
        :rtype: `Composed`

        The method is similar to the Python `str.format()` method: the string
        template supports auto-numbered (``{}``), numbered (``{0}``,
        ``{1}``...), and named placeholders (``{name}``), with positional
        arguments replacing the numbered placeholders and keywords replacing
        the named ones. However placeholder modifiers (``{0!r}``, ``{0:<10}``)
        are not supported. Only `!Composable` objects can be passed to the
        template.

        Example::

            >>> print(sql.SQL("select * from {} where {} = %s")
            ...     .format(sql.Identifier('people'), sql.Identifier('id'))
            ...     .as_string(conn))
            select * from "people" where "id" = %s

            >>> print(sql.SQL("select * from {tbl} where {pkey} = %s")
            ...     .format(tbl=sql.Identifier('people'), pkey=sql.Identifier('id'))
            ...     .as_string(conn))
            select * from "people" where "id" = %s

        """
        rv = []
        autonum = 0
        for pre, name, spec, conv in _formatter.parse(self._wrapped):
            if spec:
                raise ValueError("no format specification supported by SQL")
            if conv:
                raise ValueError("no format conversion supported by SQL")
            if pre:
                rv.append(SQL(pre))

            if name is None:
                continue

            if name.isdigit():
                if autonum:
                    raise ValueError(
                        "cannot switch from automatic field numbering to manual")
                rv.append(args[int(name)])
                autonum = None

            elif not name:
                if autonum is None:
                    raise ValueError(
                        "cannot switch from manual field numbering to automatic")
                rv.append(args[autonum])
                autonum += 1

            else:
                rv.append(kwargs[name])

        return Composed(rv)