Class RegExp
Automaton
.
Regular expressions are built from the following abstract syntax:
regexp | ::= | unionexp | ||
| | ||||
unionexp | ::= | interexp | unionexp |
(union) | |
| | interexp | |||
interexp | ::= | concatexp & interexp |
(intersection) | [OPTIONAL] |
| | concatexp | |||
concatexp | ::= | repeatexp concatexp | (concatenation) | |
| | repeatexp | |||
repeatexp | ::= | repeatexp ? |
(zero or one occurrence) | |
| | repeatexp * |
(zero or more occurrences) | ||
| | repeatexp + |
(one or more occurrences) | ||
| | repeatexp {n} |
(n occurrences) |
||
| | repeatexp {n,} |
(n or more occurrences) |
||
| | repeatexp {n,m} |
(n to m occurrences, including both) |
||
| | complexp | |||
complexp | ::= | ~ complexp |
(complement) | [OPTIONAL] |
| | charclassexp | |||
charclassexp | ::= | [ charclasses ] |
(character class) | |
| | [^ charclasses ] |
(negated character class) | ||
| | simpleexp | |||
charclasses | ::= | charclass charclasses | ||
| | charclass | |||
charclass | ::= | charexp - charexp |
(character range, including end-points) | |
| | charexp | |||
simpleexp | ::= | charexp | ||
| | . |
(any single character) | ||
| | # |
(the empty language) | [OPTIONAL] | |
| | @ |
(any string) | [OPTIONAL] | |
| | " <Unicode string without double-quotes> " |
(a string) | ||
| | ( ) |
(the empty string) | ||
| | ( unionexp ) |
(precedence override) | ||
| | < <identifier> > |
(named automaton) | [OPTIONAL] | |
| | <n-m> |
(numerical interval) | [OPTIONAL] | |
charexp | ::= | <Unicode character> | (a single non-reserved character) | |
| | \d |
(a digit [0-9]) | ||
| | \D |
(a non-digit [^0-9]) | ||
| | \s |
(whitespace [ \t\n\r]) | ||
| | \S |
(non whitespace [^\s]) | ||
| | \w |
(a word character [a-zA-Z_0-9]) | ||
| | \W |
(a non word character [^\w]) | ||
| | \ <Unicode character> |
(a single character) |
The productions marked [OPTIONAL] are only allowed if specified by the syntax
flags passed to the RegExp
constructor. The reserved characters used in the
(enabled) syntax must be escaped with backslash (\
) or double-quotes (
"..."
). (In contrast to other regexp syntaxes, this is required also in character
classes.) Be aware that dash (-
) has a special meaning in charclass
expressions. An identifier is a string not containing right angle bracket (>
) or dash (-
). Numerical intervals are specified by non-negative
decimal integers and include both end points, and if n
and m
have the same number of digits, then the conforming strings must have that length (i.e.
prefixed by 0's).
- WARNING: This API is experimental and might change in incompatible ways in the next release.
-
Nested Class Summary
Nested ClassesModifier and TypeClassDescriptionstatic enum
The type of expression represented by a RegExp node. -
Field Summary
FieldsModifier and TypeFieldDescriptionstatic final int
Syntax flag, enables all optional regexp syntax.static final int
Syntax flag, enables anystring (@
).static final int
Allows case insensitive matching of ASCII characters.static final int
Syntax flag, enables named automata (<
identifier>
).final int
Character expressionstatic final int
Syntax flag, enables complement (~
).final int
Limits for repeatable type expressionsstatic final int
Syntax flag, enables empty language (#
).final RegExp
Child expressions held by a container type expressionfinal RegExp
Child expressions held by a container type expressionfinal int
Extents for range type expressionsstatic final int
Syntax flag, enables intersection (&
).static final int
Syntax flag, enables numerical intervals (<n-m>
).final RegExp.Kind
The type of expressionfinal int
Limits for repeatable type expressionsfinal int
Limits for repeatable type expressionsstatic final int
Syntax flag, enables no optional regexp syntax.final String
String expressionfinal int
Extents for range type expressions -
Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionReturns set of automaton identifiers that occur in this regular expression.The string that was used to construct the regex.Constructs newAutomaton
from thisRegExp
.toAutomaton
(int determinizeWorkLimit) Constructs newAutomaton
from thisRegExp
.toAutomaton
(Map<String, Automaton> automata, int determinizeWorkLimit) Constructs newAutomaton
from thisRegExp
.toAutomaton
(AutomatonProvider automaton_provider, int determinizeWorkLimit) Constructs newAutomaton
from thisRegExp
.toString()
Constructs string from parsed regular expression.Like to string, but more verbose (shows the higherchy more clearly).
-
Field Details
-
INTERSECTION
public static final int INTERSECTIONSyntax flag, enables intersection (&
).- See Also:
-
COMPLEMENT
public static final int COMPLEMENTSyntax flag, enables complement (~
).- See Also:
-
EMPTY
public static final int EMPTYSyntax flag, enables empty language (#
).- See Also:
-
ANYSTRING
public static final int ANYSTRINGSyntax flag, enables anystring (@
).- See Also:
-
AUTOMATON
public static final int AUTOMATONSyntax flag, enables named automata (<
identifier>
).- See Also:
-
INTERVAL
public static final int INTERVALSyntax flag, enables numerical intervals (<n-m>
).- See Also:
-
ALL
public static final int ALLSyntax flag, enables all optional regexp syntax.- See Also:
-
NONE
public static final int NONESyntax flag, enables no optional regexp syntax.- See Also:
-
ASCII_CASE_INSENSITIVE
public static final int ASCII_CASE_INSENSITIVEAllows case insensitive matching of ASCII characters.- See Also:
-
kind
The type of expression -
exp1
Child expressions held by a container type expression -
exp2
Child expressions held by a container type expression -
s
String expression -
c
public final int cCharacter expression -
min
public final int minLimits for repeatable type expressions -
max
public final int maxLimits for repeatable type expressions -
digits
public final int digitsLimits for repeatable type expressions -
from
public final int fromExtents for range type expressions -
to
public final int toExtents for range type expressions
-
-
Constructor Details
-
RegExp
Constructs newRegExp
from a string. Same asRegExp(s, ALL)
.- Parameters:
s
- regexp string- Throws:
IllegalArgumentException
- if an error occurred while parsing the regular expression
-
RegExp
Constructs newRegExp
from a string.- Parameters:
s
- regexp stringsyntax_flags
- boolean 'or' of optional syntax constructs to be enabled- Throws:
IllegalArgumentException
- if an error occurred while parsing the regular expression
-
RegExp
Constructs newRegExp
from a string.- Parameters:
s
- regexp stringsyntax_flags
- boolean 'or' of optional syntax constructs to be enabledmatch_flags
- boolean 'or' of match behavior options such as case insensitivity- Throws:
IllegalArgumentException
- if an error occurred while parsing the regular expression
-
-
Method Details
-
toAutomaton
Constructs newAutomaton
from thisRegExp
. Same astoAutomaton(null)
(empty automaton map). -
toAutomaton
public Automaton toAutomaton(int determinizeWorkLimit) throws IllegalArgumentException, TooComplexToDeterminizeException Constructs newAutomaton
from thisRegExp
. The constructed automaton is minimal and deterministic and has no transitions to dead states.- Parameters:
determinizeWorkLimit
- maximum effort to spend while determinizing the automata. If determinizing the automata would require more than this effort, TooComplexToDeterminizeException is thrown. Higher numbers require more space but can process more complex regexes. UseOperations.DEFAULT_DETERMINIZE_WORK_LIMIT
as a decent default if you don't otherwise know what to specify.- Throws:
IllegalArgumentException
- if this regular expression uses a named identifier that is not available from the automaton providerTooComplexToDeterminizeException
- if determinizing this regexp requires more effort than determinizeWorkLimit states
-
toAutomaton
public Automaton toAutomaton(AutomatonProvider automaton_provider, int determinizeWorkLimit) throws IllegalArgumentException, TooComplexToDeterminizeException Constructs newAutomaton
from thisRegExp
. The constructed automaton is minimal and deterministic and has no transitions to dead states.- Parameters:
automaton_provider
- provider of automata for named identifiersdeterminizeWorkLimit
- maximum effort to spend while determinizing the automata. If determinizing the automata would require more than this effort, TooComplexToDeterminizeException is thrown. Higher numbers require more space but can process more complex regexes. UseOperations.DEFAULT_DETERMINIZE_WORK_LIMIT
as a decent default if you don't otherwise know what to specify.- Throws:
IllegalArgumentException
- if this regular expression uses a named identifier that is not available from the automaton providerTooComplexToDeterminizeException
- if determinizing this regexp requires more effort than determinizeWorkLimit states
-
toAutomaton
public Automaton toAutomaton(Map<String, Automaton> automata, int determinizeWorkLimit) throws IllegalArgumentException, TooComplexToDeterminizeExceptionConstructs newAutomaton
from thisRegExp
. The constructed automaton is minimal and deterministic and has no transitions to dead states.- Parameters:
automata
- a map from automaton identifiers to automata (of typeAutomaton
).determinizeWorkLimit
- maximum effort to spend while determinizing the automata. If determinizing the automata would require more than this effort, TooComplexToDeterminizeException is thrown. Higher numbers require more space but can process more complex regexes.- Throws:
IllegalArgumentException
- if this regular expression uses a named identifier that does not occur in the automaton mapTooComplexToDeterminizeException
- if determinizing this regexp requires more effort than determinizeWorkLimit states
-
getOriginalString
The string that was used to construct the regex. Compare to toString. -
toString
Constructs string from parsed regular expression. -
toStringTree
Like to string, but more verbose (shows the higherchy more clearly). -
getIdentifiers
Returns set of automaton identifiers that occur in this regular expression.
-