crawley-project/crawley

from crawley.exceptions import TemplateSyntaxError

class DSLAnalizer(object):
    """
        Analizes the DSL written by users
    """

    def __init__(self, dsl):

        self.dsl = dsl

    def is_header(self, line):

        return DSLHeaderLine.SEPARATOR in line

    def parse(self):

        blocks = []
        lines = []

        for n, line in enumerate(self.dsl.split("\n")):

            line = line.strip()

            if not line:
                continue

            if self.is_header(line):

                if lines:
                    blocks.append(lines)

                lines = []
                lines.append(DSLHeaderLine(line, n))

            else:
                lines.append(DSLLine(line, n))

        blocks.append(lines)
        return blocks


class DSLLine(object):
    """
        A DSL line abstraction
    """

    SEPARATOR = "->"
    is_header = False

    def __init__(self, content, number):

        self.number = number
        self.content = content
        self._parse()

    def _parse(self):

        parts = self.content.split(self.SEPARATOR)

        if len(parts) > 2:
            raise TemplateSyntaxError(self.number, "More than one '%s' token found in the same line" % self.SEPARATOR)

        if len(parts) < 2:
            raise TemplateSyntaxError(self.number, "Missed separator token '%s'" % self.SEPARATOR)

        self.field = self._parse_attribs(parts[0])
        self.xpath = parts[1].strip()

    def _parse_attribs(self, parmas):

        table, column = parmas.split(".")
        return {"table" : table.strip(), "column" : column.strip()}


class DSLHeaderLine(DSLLine):

    SEPARATOR = "=>"
    is_header = True

    def _parse_attribs(self, field):

        return field