Coverage for /pythoncovmergedfiles/medio/medio/usr/local/lib/python3.8/site-packages/lark/parsers/earley_common.py: 85%

1"""This module implements useful building blocks for the Earley parser 

2""" 

3 

4 

5class Item: 

6 "An Earley Item, the atom of the algorithm." 

7 

8 __slots__ = ('s', 'rule', 'ptr', 'start', 'is_complete', 'expect', 'previous', 'node', '_hash') 

9 def __init__(self, rule, ptr, start): 

10 self.is_complete = len(rule.expansion) == ptr 

11 self.rule = rule # rule 

12 self.ptr = ptr # ptr 

13 self.start = start # j 

14 self.node = None # w 

15 if self.is_complete: 

16 self.s = rule.origin 

17 self.expect = None 

18 self.previous = rule.expansion[ptr - 1] if ptr > 0 and len(rule.expansion) else None 

19 else: 

20 self.s = (rule, ptr) 

21 self.expect = rule.expansion[ptr] 

22 self.previous = rule.expansion[ptr - 1] if ptr > 0 and len(rule.expansion) else None 

23 self._hash = hash((self.s, self.start)) 

24 

25 def advance(self): 

26 return Item(self.rule, self.ptr + 1, self.start) 

27 

28 def __eq__(self, other): 

29 return self is other or (self.s == other.s and self.start == other.start) 

30 

31 def __hash__(self): 

32 return self._hash 

33 

34 def __repr__(self): 

35 before = ( expansion.name for expansion in self.rule.expansion[:self.ptr] ) 

36 after = ( expansion.name for expansion in self.rule.expansion[self.ptr:] ) 

37 symbol = "{} ::= {}* {}".format(self.rule.origin.name, ' '.join(before), ' '.join(after)) 

38 return '%s (%d)' % (symbol, self.start) 

39 

40 

41# class TransitiveItem(Item): 

42# ... # removed at commit 4c1cfb2faf24e8f8bff7112627a00b94d261b420