fetched mlz version
- before some chamges in the gerrit pipline Change-Id: I33eb2d75f83345a7039d0fb709e66defefb1c3e0
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179
frappy/parse.py
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179
frappy/parse.py
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# -*- coding: utf-8 -*-
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# *****************************************************************************
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#
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# This program is free software; you can redistribute it and/or modify it under
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# the terms of the GNU General Public License as published by the Free Software
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# Foundation; either version 2 of the License, or (at your option) any later
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# version.
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#
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# This program is distributed in the hope that it will be useful, but WITHOUT
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# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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# FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
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# details.
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#
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# You should have received a copy of the GNU General Public License along with
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# this program; if not, write to the Free Software Foundation, Inc.,
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# 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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#
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# Module authors:
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# Enrico Faulhaber <enrico.faulhaber@frm2.tum.de>
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#
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# *****************************************************************************
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"""parser. used for config files and the gui
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can't use ast.literal_eval as we want less strict syntax (strings without quotes)
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parsing rules:
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(...) -> tuple
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[...] -> tuple
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{text:...} -> dict
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{text=...} -> dict
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..., ... -> tuple
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digits -> float or int (try int, if it fails: take float)
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text -> string
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'text' -> string
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"text" -> string
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further conversions are done by the validator of the datatype....
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"""
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# TODO: should be refactored to use Exceptions instead of None in return tuple
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# also it would be better to use functions instead of a class
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from collections import OrderedDict
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class Parser:
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# all parsing methods return (parsed value, remaining string)
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# or (None, remaining_text) if parsing error
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def parse_number(self, text):
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text = text.strip()
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l = 1
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number = None
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while l <= len(text):
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try:
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number = float(text[:l])
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length = l
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l += 1
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except ValueError:
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if text[l - 1] in 'eE+-':
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l += 1
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continue
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if number is None:
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return None, text
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try:
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# TODO: check allthough length is unset in it. 1, number is None, never reaching the try
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# pylint: disable=used-before-assignment
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return int(text[:length]), text[length:]
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except ValueError:
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return number, text[length:]
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return number, ''
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def parse_string(self, orgtext):
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# handle quoted and unquoted strings correctly
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text = orgtext.strip()
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if text[0] in ('"', "'"):
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# quoted string
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quote = text[0]
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idx = 0
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while True:
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idx = text.find(quote, idx + 1)
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if idx == -1:
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return None, orgtext
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# check escapes!
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if text[idx - 1] == '\\':
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continue
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return text[1:idx], text[idx + 1:].strip()
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# unquoted strings are terminated by comma or whitespace
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idx = 0
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while idx < len(text):
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if text[idx] in '\x09 ,.;:()[]{}<>-+*/\\!"§$%&=?#~+*\'´`^°|-':
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break
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idx += 1
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return text[:idx] or None, text[idx:].strip()
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def parse_tuple(self, orgtext):
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text = orgtext.strip()
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bra = text[0]
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if bra not in '([<':
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return None, orgtext
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# convert to closing bracket
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bra = ')]>'['([<'.index(bra)]
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reslist = []
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# search for closing bracket, collecting results
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text = text[1:]
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while text:
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if bra not in text:
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return None, text
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res, rem = self.parse_sub(text)
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if res is None:
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print(f'remtuple {rem!r} {text!r} {bra!r}')
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if rem[0] == bra:
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# allow trailing separator
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return tuple(reslist), rem[1:].strip()
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return None, text
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reslist.append(res)
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if rem[0] == bra:
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return tuple(reslist), rem[1:].strip()
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# eat separator
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if rem[0] in ',;':
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text = rem[1:]
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else:
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return None, rem
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return None, orgtext
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def parse_dict(self, orgtext):
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text = orgtext.strip()
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if text[0] != '{':
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return None, orgtext
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# keep ordering
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result = OrderedDict()
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# search for closing bracket, collecting results
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# watch for key=value or key:value pairs, separated by ,
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text = text[1:]
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while '}' in text:
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# first part is always a string
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key, rem = self.parse_string(text)
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if key is None:
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if rem[0] == '}':
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# allow trailing separator
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return result, rem[1:].strip()
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return None, orgtext
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if rem[0] not in ':=':
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return None, rem
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# eat separator
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text = rem[1:]
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value, rem = self.parse_sub(text)
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if value is None:
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return None, orgtext
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result[key] = value
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if rem[0] == '}':
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return result, rem[1:].strip()
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if rem[0] not in ',;':
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return None, rem
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# eat separator
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text = rem[1:]
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return None, text
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def parse_sub(self, orgtext):
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text = orgtext.strip()
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if not text:
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return None, orgtext
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if text[0] in '+-.0123456789':
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return self.parse_number(orgtext)
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if text[0] == '{':
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return self.parse_dict(orgtext)
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if text[0] in '([<':
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return self.parse_tuple(orgtext)
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return self.parse_string(orgtext)
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def parse(self, orgtext):
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res, rem = self.parse_sub(orgtext)
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if rem and rem[0] in ',;':
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return self.parse_sub(f'[{orgtext}]')
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return res, rem
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