Classes for nodes in the Expression tree
Expression
|--- Any - match (or don't match) a set of characters
|--- AnyEol - match any newline representation ("\n", "\r" or "\r\n")
|--- Assert - used for positive and negative lookahead assertions
|--- AtBeginning - match the beginning of a line
|--- AtEnd - match the end of a line
|--- Debug - print a debug message
|--- Dot - match any character except newline
|--- Group - give a group name to an expression
|--- GroupRef - match a previously identified expression
|--- Literal - match (or don't match) a single character
|--- MaxRepeat - greedy repeat of an expression, within min/max bounds
|--- NullOp - does nothing (useful as an initial seed)
|--- PassThrough - used when overriding 'make_parser'; match its subexp
| |--- FastFeature - keeps information about possibly optional tags
| |--- HeaderFooter - files with a header, records and a footer
| `--- ParseRecords - parse a record at a time
|--- Str - match a given string
`--- ExpressionList - expressions containing several subexpressions
|--- Alt - subexp1 or subexp2 or subexp3 or ...
`--- Seq - subexp1 followed by subexp2 followed by subexp3 ...
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Imported modules
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import Parser
import msre_parse
import re
import string
from xml.sax import xmlreader
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Functions
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NoCase
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NoCase ( expr )
expression -> expression where the text is case insensitive
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_make_fast_lookup
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_make_fast_lookup ()
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_make_group_pattern
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_make_group_pattern (
name,
expression,
attrs,
)
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_make_no_case
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_make_no_case ( node )
modify an expression in place to remove case dependencies
may return a new top-level node
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_minimize_any_range
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_minimize_any_range ( s )
s -> a string useable inside [] which matches all the characters in s
For example, passing in "0123456789" returns "\d".
This code isn't perfect.
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_minimize_escape_char
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_minimize_escape_char ( c )
(c) -> into an appropriately escaped pattern for the character
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_minimize_escape_range
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_minimize_escape_range ( c1, c2 )
(c1, c2) -> the pattern for the range bounded by those two characters
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_quote
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_quote ( s )
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_verify_name
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_verify_name ( s )
Group names must be valid XML identifiers
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Exceptions
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AssertionError, "Illegal character in group name %s" % repr( s )
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escape
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escape ( pattern )
Escape all non-alphanumeric characters in pattern.
taken from re.escape, except also don't escape " ="
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Classes
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| Alt |
An Expression tree with a list of alternate matches.
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| Any |
Any character in a given set: '[abc]
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| AnyEol |
Match a newline ("
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| Assert |
Lookahead assertions: (?=...)
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| AtBeginning |
Match the beginning of a line
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| AtEnd |
Match the end of a line
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| Debug |
Print a message when there is a match at this point.
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| Dot |
Match any character except newline
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| Expression |
Base class for nodes in the Expression tree
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| ExpressionList |
shares implementation used by 'Expressions with subexpressions
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| FastFeature | |
| Group | |
| GroupRef |
group reference: '(?P<name>.)(?P=name)
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| HeaderFooter | |
| Literal |
A single character: a
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| MaxRepeat |
Greedy repeat: a*
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| NullOp |
does nothing
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| ParseRecords |
Might be useful to allow a minimum record count (likely either 0 or 1)
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| PassThrough |
Match the subexpression.
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| Seq |
An Expression matching a set of subexpressions, in sequential order
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| Str |
A sequence of characters: 'abcdef
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