Class RegexpChunkRule
source code
object --+
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RegexpChunkRule
- Known Subclasses:
-
ChinkRule,
ChunkRule,
ExpandLeftRule,
ExpandRightRule,
MergeRule,
SplitRule,
UnChunkRule
A rule specifying how to modify the chunking in a
ChunkString
, using a transformational regular expression.
The RegexpChunkRule
class itself can be used to implement
any transformational rule based on regular expressions. There are also a
number of subclasses, which can be used to implement simpler types of
rules, based on matching regular expressions.
Each RegexpChunkRule
has a regular expression and a
replacement expression. When a RegexpChunkRule
is applied to a
ChunkString
, it searches the ChunkString
for
any substring that matches the regular expression, and replaces it using
the replacement expression. This search/replace operation has the same
semantics as re.sub
.
Each RegexpChunkRule
also has a description string, which
gives a short (typically less than 75 characters) description of the
purpose of the rule.
This transformation defined by this RegexpChunkRule
should only add and remove braces; it should not modify the
sequence of angle-bracket delimited tags. Furthermore, this
transformation may not result in nested or mismatched bracketing.
__init__(self,
regexp,
repl,
descr)
(Constructor)
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Construct a new RegexpChunkRule.
- Parameters:
regexp (regexp or string ) - This RegexpChunkRule 's regular expression. When this
rule is applied to a ChunkString , any substring that
matches regexp will be replaced using the
replacement string repl . Note that this must be a
normal regular expression, not a tag pattern.
repl (string ) - This RegexpChunkRule 's replacement expression. When
this rule is applied to a ChunkString , any substring
that matches regexp will be replaced using
repl .
descr (string ) - A short description of the purpose and/or effect of this rule.
- Overrides:
object.__init__
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Apply this rule to the given ChunkString . See the class
reference documentation for a description of what it means to apply a
rule.
- Parameters:
chunkstr (ChunkString ) - The chunkstring to which this rule is applied.
- Returns:
None
- Raises:
ValueError - If this transformation generated an invalid chunkstring.
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- Returns:
string
- a short description of the purpose and/or effect of this rule.
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repr(x)
- Returns:
string
- A string representation of this rule. This string representation
has the form:
<RegexpChunkRule: '{<IN|VB.*>}'->'<IN>'>
Note that this representation does not include the description
string; that string can be accessed separately with the
descr method.
- Overrides:
object.__repr__
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