Code.py

from __future__ import absolute_import
# Copyright (C) 2007-2010 Samuel Abels.
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License version 2, as
# published by the Free Software Foundation.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
import re
import Exscript.interpreter.Template
from Exscript.interpreter.Scope        import Scope
from Exscript.interpreter.Append       import Append
from Exscript.interpreter.Assign       import Assign
from Exscript.interpreter.Enter        import Enter
from Exscript.interpreter.Extract      import Extract
from Exscript.interpreter.Fail         import Fail
from Exscript.interpreter.FunctionCall import FunctionCall
from Exscript.interpreter.IfCondition  import IfCondition
from Exscript.interpreter.Loop         import Loop
from Exscript.interpreter.Try          import Try
from Exscript.interpreter.String       import varname_re

varname  = varname_re.pattern
keywords = ['append',
            'as',
            'else',
            'end',
            'enter',
            'extract',
            'fail',
            'false',
            'from',
            'if',
            'into',
            'loop',
            'try',
            'to',
            'true',
            'until',
            'when',
            'while']
operators = ['in',
             r'not\s+in',
             r'is\s+not',
             'is',
             'ge',
             'gt',
             'le',
             'lt',
             'matches']

grammar = (
    ('escaped_data',        r'\\.'),
    ('regex_delimiter',     r'/'),
    ('string_delimiter',    r'"'),
    ('open_curly_bracket',  r'{'),
    ('close_curly_bracket', r'}'),
    ('close_bracket',       r'\)'),
    ('comma',               r','),
    ('whitespace',          r'[ \t]+'),
    ('keyword',             r'\b(?:' + '|'.join(keywords)  + r')\b'),
    ('assign',              r'='),
    ('octal_number',        r'0\d+'),
    ('hex_number',          r'0x(?:\w\w)+'),
    ('comparison',          r'\b(?:' + '|'.join(operators) + r')\b'),
    ('arithmetic_operator', r'(?:\*|\+|-|%|\.)'),
    ('logical_operator',    r'\b(?:and|or|not)\b'),
    ('open_function_call',  varname + r'(?:\.' + varname + r')*\('),
    ('varname',             varname),
    ('number',              r'\d+'),
    ('newline',             r'[\r\n]'),
    ('raw_data',            r'[^\r\n{}]+')
)

grammar_c = []
for thetype, regex in grammar:
    grammar_c.append((thetype, re.compile(regex)))

class Code(Scope):
    def __init__(self, lexer, parser, parent):
        Scope.__init__(self, 'Code', lexer, parser, parent)
        lexer.set_grammar(grammar_c)
        while True:
            lexer.skip(['whitespace', 'newline'])
            if lexer.next_if('close_curly_bracket'):
                if isinstance(parent, Exscript.interpreter.Template.Template):
                    break
                self.add(Exscript.interpreter.Template.Template(lexer, parser, self))
            elif lexer.current_is('keyword', 'append'):
                self.add(Append(lexer, parser, self))
            elif lexer.current_is('keyword', 'extract'):
                self.add(Extract(lexer, parser, self))
            elif lexer.current_is('keyword', 'fail'):
                self.add(Fail(lexer, parser, self))
            elif lexer.current_is('keyword', 'if'):
                self.add(IfCondition(lexer, parser, self))
            elif lexer.current_is('keyword', 'loop'):
                self.add(Loop(lexer, parser, self))
            elif lexer.current_is('varname'):
                self.add(Assign(lexer, parser, self))
            elif lexer.current_is('keyword', 'try'):
                self.add(Try(lexer, parser, self))
            elif lexer.current_is('keyword', 'enter'):
                self.add(Enter(lexer, parser, self))
            elif lexer.current_is('keyword', 'else'):
                if not isinstance(parent, Code):
                    lexer.syntax_error('"end" without a scope start', self)
                break
            elif lexer.next_if('keyword', 'end'):
                if not isinstance(parent, Code):
                    lexer.syntax_error('"end" without a scope start', self)
                lexer.skip(['whitespace', 'newline'])
                break
            elif lexer.current_is('open_function_call'):
                self.add(FunctionCall(lexer, parser, self))
            else:
                lexer.syntax_error('Unexpected %s "%s"' % lexer.token(), self)
        lexer.restore_grammar()