character

object character

This module contains many parsers to do with reading one or more characters. Almost every parser will need something from this module.

In particular, this module contains: combinators that can read specific characters; combinators that represent character classes and their negations; combinators for reading specific strings; as well as a selection of pre-made parsers to parse specific kinds of character, like digits and letters.

Source: character.scala
Since: 2.2.0

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final def !=(arg0: Any): Boolean
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final def ##: Int
Definition Classes
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final def ==(arg0: Any): Boolean
Definition Classes
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final def asInstanceOf[T0]: T0
Definition Classes
Any
val bit: Parsley[Char]
This parser tries to parse a bit and returns it if successful.
This parser tries to parse a bit and returns it if successful.
A bit (binary digit) is either '0' or '1'.
def char(c: Char): Parsley[Char]
This combinator tries to parse a single specific character c from the input.
This combinator tries to parse a single specific character c from the input.
Attempts to read the given character c from the input stream at the current position. If this character can be found, it is consumed and returned. Otherwise, no input is consumed and this combinator will fail.
c
the character to parse
returns
a parser that tries to read a single c, or fails.
Example:
1. scala> import parsley.character.char scala> char('a').parse("") val res0 = Failure(..) scala> char('a').parse("a") val res1 = Success('a') scala> char('a').parse("ba") val res2 = Failure(..)
Note
this combinator can only handle 16-bit characters: for larger codepoints, consider using string.
def clone(): AnyRef
Attributes
protected[lang]
Definition Classes
AnyRef
Annotations
@throws(classOf[java.lang.CloneNotSupportedException]) @native()
val crlf: Parsley[Char]
This parser tries to parse a CRLF newline character pair, returning '\n' if successful.
This parser tries to parse a CRLF newline character pair, returning '\n' if successful.
A CRLF character is the pair of carriage return ('\r') and line feed ('\n'). These two characters will be parsed together or not at all. The parser is made atomic using attempt.
val digit: Parsley[Char]
This parser tries to parse a digit, and returns it if successful.
This parser tries to parse a digit, and returns it if successful.
A digit is any character c <= '\uFFFF' whose Unicode Category Type is Decimal Number (Nd). Examples of (inclusive) ranges within this category include:
- the Latin digits '0' through '9'
- the Arabic-Indic digits '\u0660' through '\u0669'
- the Extended Arabic-Indic digits '\u06F0' through '\u06F9'
- the Devangari digits '\u0966' through '\u096F'
- the Fullwidth digits '\uFF10' through '\uFF19'
The full list of codepoints found in a category can be found in the Unicode Character Database.
val endOfLine: Parsley[Char]
This parser will parse either a line feed (LF) or a CRLF newline, returning '\n' if successful.
This parser will parse either a line feed (LF) or a CRLF newline, returning '\n' if successful.
See also
crlf
final def eq(arg0: AnyRef): Boolean
Definition Classes
AnyRef
def equals(arg0: AnyRef): Boolean
Definition Classes
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def finalize(): Unit
Attributes
protected[lang]
Definition Classes
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@throws(classOf[java.lang.Throwable])
final def getClass(): Class[_ <: AnyRef]
Definition Classes
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Annotations
@native()
def hashCode(): Int
Definition Classes
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Annotations
@native()
val hexDigit: Parsley[Char]
This parser tries to parse a hexadecimal digit, and returns it if successful.
This parser tries to parse a hexadecimal digit, and returns it if successful.
A hexadecimal digit is one of (all inclusive ranges):
1. the digits '0' through '9'
2. the letters 'a' through 'f'
3. the letters 'A' through 'Z'
See also
isHexDigit
def isHexDigit(c: Char): Boolean
This function returns true if a character is a hexadecimal digit.
This function returns true if a character is a hexadecimal digit.
A hexadecimal digit is one of (all inclusive ranges):
1. the digits '0' through '9'
2. the letters 'a' through 'f'
3. the letters 'A' through 'Z'
See also
hexDigit
final def isInstanceOf[T0]: Boolean
Definition Classes
Any
def isOctDigit(c: Char): Boolean
This function returns true if a character is an octal digit.
This function returns true if a character is an octal digit.
An octal digit is one of '0' to '7' (inclusive).
See also
octDigit
def isSpace(c: Char): Boolean
This function returns true if a character is either a space or a tab character.
This function returns true if a character is either a space or a tab character.
See also
space
def isWhitespace(c: Char): Boolean
This function returns true if a character is a whitespace character.
This function returns true if a character is a whitespace character.
A whitespace character is one of:
1. a space (' ')
2. a tab ('\t')
3. a line feed ('\n')
4. a carriage return ('\r')
5. a form feed ('\f')
6. a vertical tab ('\u000B')
See also
whitespace
val item: Parsley[Char]
This parser will parse any single character from the input, failing if there is no input remaining.
This parser will parse any single character from the input, failing if there is no input remaining.
Note
this combinator can only handle 16-bit characters.
val letter: Parsley[Char]
This parser tries to parse a letter, and returns it if successful.
This parser tries to parse a letter, and returns it if successful.
A letter is any character c <= '\uFFFF' whose Unicode Category Type is any of the following:
1. Uppercase Letter (Lu)
2. Lowercase Letter (Ll)
3. Titlecase Letter (Lt)
4. Modifier Letter (Lm)
5. Other Letter (Lo)
The full list of codepoints found in a category can be found in the Unicode Character Database.
val letterOrDigit: Parsley[Char]
This parser tries to parse either a letter or a digit, and returns it if successful.
This parser tries to parse either a letter or a digit, and returns it if successful.
A letter or digit is anything that would parse in either letter or digit.
See also
documentation for letter.
documentation for digit.
val lower: Parsley[Char]
This parser tries to parse a lowercase letter, and returns it if successful.
This parser tries to parse a lowercase letter, and returns it if successful.
A lowercase letter is any character c <= '\uFFFF' whose Unicode Category Type is Lowercase Letter (Ll). Examples of characters within this category include:
- the Latin letters 'a' through 'z'
- Latin special character such as 'é', 'ß', 'ð'
- Cryillic letters
- Greek letters
- Coptic letters
The full list of codepoints found in a category can be found in the Unicode Character Database.
final def ne(arg0: AnyRef): Boolean
Definition Classes
AnyRef
val newline: Parsley[Char]
This parser tries to parse a line feed newline ('\n') character, and returns it if successful.
This parser tries to parse a line feed newline ('\n') character, and returns it if successful.
This parser will not accept a carriage return (CR) character or CRLF.
def noneOf(cs: NumericRange[Char]): Parsley[Char]
This combinator tries to parse any character not from supplied set of characters cs, returning it if successful.
This combinator tries to parse any character not from supplied set of characters cs, returning it if successful.
If the next character in the input is outside of the range of characters cs, it is consumed and returned. Otherwise, no input is consumed and the combinator fails.
cs
the range of characters to check.
returns
a parser that parses a character outside the range cs.
Example:
1. scala> import parsley.character.noneOf scala> val p = noneOf('a' to 'c') scala> p.parse("a") val res0 = Failure(..) scala> p.parse("b") val res1 = Failure(..) scala> p.parse("c") val res1 = Failure(..) scala> p.parse("xb") val res2 = Success('x') scala> p.parse("") val res3 = Failure(..)
Note
this combinator can only handle 16-bit characters.
See also
satisfy
def noneOf(cs: Char*): Parsley[Char]
This combinator tries to parse any character not from supplied set of characters cs, returning it if successful.
This combinator tries to parse any character not from supplied set of characters cs, returning it if successful.
If the next character in the input is not an element of the list of characters cs, it is consumed and returned. Otherwise, no input is consumed and the combinator fails.
cs
the set of characters to check.
returns
a parser that parses one character that is not an element of cs.
Example:
1. scala> import parsley.character.noneOf scala> val p = noneOf('a', 'b', 'c') scala> p.parse("a") val res0 = Failure(..) scala> p.parse("c") val res1 = Failure(..) scala> p.parse("xb") val res2 = Success('x') scala> p.parse("") val res3 = Failure(..)
Note
this combinator can only handle 16-bit characters.
See also
satisfy
def noneOf(cs: Set[Char]): Parsley[Char]
This combinator tries to parse any character not from supplied set of characters cs, returning it if successful.
This combinator tries to parse any character not from supplied set of characters cs, returning it if successful.
If the next character in the input is not a member of the set cs, it is consumed and returned. Otherwise, no input is consumed and the combinator fails.
cs
the set of characters to check.
returns
a parser that parses one character that is not a member of the set cs.
Example:
1. scala> import parsley.character.noneOf scala> val p = noneOf(Set('a', 'b', 'c')) scala> p.parse("a") val res0 = Failure(..) scala> p.parse("c") val res1 = Failure(..) scala> p.parse("xb") val res2 = Success('x') scala> p.parse("") val res3 = Failure(..)
Note
this combinator can only handle 16-bit characters.
See also
satisfy
final def notify(): Unit
Definition Classes
AnyRef
Annotations
@native()
final def notifyAll(): Unit
Definition Classes
AnyRef
Annotations
@native()
val octDigit: Parsley[Char]
This parser tries to parse an octal digit, and returns it if successful.
This parser tries to parse an octal digit, and returns it if successful.
An octal digit is one of '0' to '7' (inclusive).
See also
isOctDigit
def oneOf(cs: NumericRange[Char]): Parsley[Char]
This combinator tries to parse any character from supplied set of characters cs, returning it if successful.
This combinator tries to parse any character from supplied set of characters cs, returning it if successful.
If the next character in the input is within the range of characters cs, it is consumed and returned. Otherwise, no input is consumed and the combinator fails.
cs
the range of characters to check.
returns
a parser that parses a character within the range cs.
Example:
1. scala> import parsley.character.oneOf scala> val p = oneOf('a' to 'c') scala> p.parse("a") val res0 = Success('a') scala> p.parse("b") val res1 = Success('b') scala> p.parse("c") val res1 = Success('c') scala> p.parse("xb") val res2 = Failure(..)
Note
this combinator can only handle 16-bit characters.
See also
satisfy
def oneOf(cs: Char*): Parsley[Char]
This combinator tries to parse any character from supplied set of characters cs, returning it if successful.
This combinator tries to parse any character from supplied set of characters cs, returning it if successful.
If the next character in the input is an element of the list of characters cs, it is consumed and returned. Otherwise, no input is consumed and the combinator fails.
cs
the characters to check.
returns
a parser that parses one of the elements of cs.
Example:
1. scala> import parsley.character.oneOf scala> val p = oneOf('a', 'b', 'c') scala> p.parse("a") val res0 = Success('a') scala> p.parse("c") val res1 = Success('c') scala> p.parse("xb") val res2 = Failure(..)
Note
this combinator can only handle 16-bit characters.
See also
satisfy
def oneOf(cs: Set[Char]): Parsley[Char]
This combinator tries to parse any character from supplied set of characters cs, returning it if successful.
This combinator tries to parse any character from supplied set of characters cs, returning it if successful.
If the next character in the input is a member of the set cs, it is consumed and returned. Otherwise, no input is consumed and the combinator fails.
cs
the set of characters to check.
returns
a parser that parses one of the member of the set cs.
Example:
1. scala> import parsley.character.oneOf scala> val p = oneOf(Set('a', 'b', 'c')) scala> p.parse("a") val res0 = Success('a') scala> p.parse("c") val res1 = Success('c') scala> p.parse("xb") val res2 = Failure(..)
Note
this combinator can only handle 16-bit characters.
See also
satisfy
def satisfy(pred: (Char) => Boolean): Parsley[Char]
This combinator tries to parse a single character from the input that matches the given predicate.
This combinator tries to parse a single character from the input that matches the given predicate.
Attempts to read a character from the input and tests it against the predicate pred. If a character c can be read and pred(c) is true, then c is consumed and returned. Otherwise, no input is consumed and this combinator will fail.
pred
the predicate to test the next character against, should one exist.
returns
a parser that tries to read a single character c, such that pred(c) is true, or fails.
Example:
1. scala> import parsley.character.satisfy scala> satisfy(_.isDigit).parse("") val res0 = Failure(..) scala> satisfy(_.isDigit).parse("7") val res1 = Success('7') scala> satisfy(_.isDigit).parse("a5") val res2 = Failure(..) scala> def char(c: Char): Parsley[Char] = satisfy(_ == c)
Note
this combinator can only handle 16-bit characters.
val space: Parsley[Char]
This parser tries to parse a space or tab character, and returns it if successful
This parser tries to parse a space or tab character, and returns it if successful
See also
isSpace
val spaces: Parsley[Unit]
This parser skips zero or more space characters using space.
This parser skips zero or more space characters using space.
See also
combinator.skipMany
def string(s: String): Parsley[String]
This combinator attempts to parse a given string from the input, and fails otherwise.
This combinator attempts to parse a given string from the input, and fails otherwise.
Attempts to read the given string completely from the input at the current position. If the string is present, then the parser succeeds, and the entire string is consumed from the input. Otherwise, if the input has too few characters remaining, or not all the characters matched, the parser fails. On failure, all the characters that were matched are consumed from the input.
s
the string to be parsed from the input
returns
a parser that either parses the string s or fails at the first mismatched character.
Example:
1. scala> import parsley.character.string scala> string("abc").parse("") val res0 = Failure(..) scala> string("abc").parse("abcd") val res1 = Success("abc") scala> string("abc").parse("xabc") val res2 = Failure(..)
Note
the error messages generated by string do not reflect how far into the input it managed to get: this is because the error being positioned at the start of the string is more natural. However, input will still be consumed for purposes of backtracking.
def stringOfMany(pc: Parsley[Char]): Parsley[String]
This combinator parses pc zero or more times, collecting its results into a string.
This combinator parses pc zero or more times, collecting its results into a string.
Parses pc repeatedly until it fails. The resulting characters are placed into a string, which is then returned. This is morally equivalent to many(pc).map(_.mkString), but it uses StringBuilder, which makes it much more efficient.
pc
the parser whose results make up the string
returns
a parser that parses a string whose letters consist of results from pc.
Example:
1. scala> import parsley.character.{letter, letterOrDigit, stringOfMany} scala> import parsley.implicits.zipped.Zipped2 scala> val ident = (letter, stringOfMany(letterOrDigit)).zipped((c, s) => s"$c$s") scala> ident.parse("abdc9d") val res0 = Success("abdc9d") scala> ident.parse("a") val res1 = Success("a") scala> ident.parse("9") val res2 = Failure(..)
Since
4.0.0
def stringOfSome(pc: Parsley[Char]): Parsley[String]
This combinator parses pc one or more times, collecting its results into a string.
This combinator parses pc one or more times, collecting its results into a string.
Parses pc repeatedly until it fails. The resulting characters are placed into a string, which is then returned. This is morally equivalent to many(pc).map(_.mkString), but it uses StringBuilder, which makes it much more efficient. The result string must have at least one character in it.
pc
the parser whose results make up the string
returns
a parser that parses a string whose letters consist of results from pc.
Example:
1. scala> import parsley.character.{letter, stringOfSome} scala> val ident = stringOfSome(letter) scala> ident.parse("abdc9d") val res0 = Success("abdc") scala> ident.parse("") val res1 = Failure(..)
Since
4.0.0
def strings[A](kv0: (String, Parsley[A]), kvs: (String, Parsley[A])*): Parsley[A]
This combinator tries to parse each of the key-value pairs kvs (and kv0), until one of them succeeds.
This combinator tries to parse each of the key-value pairs kvs (and kv0), until one of them succeeds.
Each argument to this combinator is a pair of a string and a parser to perform if that string can be parsed. strings(s0 -> p0, ...) can be thought of as attemptChoice(string(s0) *> p0, ...), however, the given ordering of key-value pairs does not dictate the order in which the parses are tried. In particular, it will favour keys that are the prefix of another key first, so that it has Longest Match semantics. it will try to minimise backtracking too, making it a much more efficient option than attemptChoice.
kv0
the first key-value pair to try to parse.
kvs
the remaining key-value pairs to try to parse.
returns
a parser that tries to parse all the given key-value pairs, returning the (possibly failing) result of the value that corresponds to the longest matching key.
Example:
1. scala> import parsley.character.strings scala> val p = strings("hell" -> pure(4), "hello" -> pure(5), "goodbye" -> pure(7), "g" -> pure(1), "abc" -> pure(3)) scala> p.parse("hell") val res0 = Success(4) scala> p.parse("hello") val res1 = Success(5) scala> p.parse("good") val res2 = Success(1) scala> p.parse("goodbye") val res3 = Success(7) scala> p.parse("a") val res4 = Failure(..)
Since
4.0.0
Note
the scope of any backtracking performed is isolated to the key itself, as it is assumed that once a key parses correctly, the branch has been committed to. Putting an attempt around the values will not affect this behaviour.
def strings(str0: String, strs: String*): Parsley[String]
This combinator tries to parse each of the strings strs (and str0), until one of them succeeds.
This combinator tries to parse each of the strings strs (and str0), until one of them succeeds.
Unlike choice, or more accurately attemptChoice, this combinator will not necessarily parse the strings in the order provided. It will favour strings that have another string as a prefix first, so that it has Longest Match semantics. It will try to minimise backtracking too, making it a much more efficient option than attemptChoice.
The longest succeeding string will be returned. If no strings match then the combinator fails.
str0
the first string to try to parse.
strs
the remaining strings to try to parse.
returns
a parser that tries to parse all the given strings returning the longest one that matches.
Example:
1. scala> import parsley.character.strings scala> val p = strings("hell", "hello", "goodbye", "g", "abc") scala> p.parse("hell") val res0 = Success("hell") scala> p.parse("hello") val res1 = Success("hello") scala> p.parse("good") val res2 = Success("g") scala> p.parse("goodbye") val res3 = Success("goodbye") scala> p.parse("a") val res4 = Failure(..)
Since
4.0.0
final def synchronized[T0](arg0: => T0): T0
Definition Classes
AnyRef
val tab: Parsley[Char]
This parser tries to parse a tab ('\t') character, and returns it if successful.
This parser tries to parse a tab ('\t') character, and returns it if successful.
This parser does not recognise vertical tabs, only horizontal ones.
def toString(): String
Definition Classes
AnyRef → Any
val upper: Parsley[Char]
This parser tries to parse an uppercase letter, and returns it if successful.
This parser tries to parse an uppercase letter, and returns it if successful.
An uppercase letter is any character c <= '\uFFFF' whose Unicode Category Type is Uppercase Letter (Lu). Examples of characters within this category include:
- the Latin letters 'A' through 'Z'
- Latin special character such as 'Å', 'Ç', 'Õ'
- Cryillic letters
- Greek letters
- Coptic letters
The full list of codepoints found in a category can be found in the Unicode Character Database.
final def wait(): Unit
Definition Classes
AnyRef
Annotations
@throws(classOf[java.lang.InterruptedException])
final def wait(arg0: Long, arg1: Int): Unit
Definition Classes
AnyRef
Annotations
@throws(classOf[java.lang.InterruptedException])
final def wait(arg0: Long): Unit
Definition Classes
AnyRef
Annotations
@throws(classOf[java.lang.InterruptedException]) @native()
val whitespace: Parsley[Char]
This parser tries to parse a whitespace character, and returns it if successful.
This parser tries to parse a whitespace character, and returns it if successful.
A whitespace character is one of:
1. a space (' ')
2. a tab ('\t')
3. a line feed ('\n')
4. a carriage return ('\r')
5. a form feed ('\f')
6. a vertical tab ('\u000B')
See also
isWhitespace
val whitespaces: Parsley[Unit]
This parser skips zero or more space characters using whitespace.
This parser skips zero or more space characters using whitespace.
See also
combinator.skipMany

Inherited from AnyRef

Inherited from Any

Core Combinators and Parsers

These are the most primitive combinators for consuming input capable of any input reading tasks.

Character Class Combinators

These combinators allow for working with character classes. This means that a set, or range, of characters can be specified, and the combinator will return a parser that matches one of those characters (or conversely, any character that is not in that set). The parsed character is always returned.

String Combinators

These combinators allow for working with, or building, strings. This means that they can parse specific strings, specific sets of strings, or can read characters repeatedly to generate strings. They are united in all returning String as their result.

Specific Character Parsers

These parsers are special cases of satisfy or char. They are worth using, as they are given special error labelling, producing nicer error messages than their primitive counterparts. This documentation assumes JDK 17. JDK 17 is compliant with Unicode® Specification 13.0. As such, the descriptions of the parsers in this section are accurate with respect to Unicode® Specification 13.0: using a different JDK may affect the precise definitions of the parsers below. If in doubt, check the documentation for java.lang.Character to see which Unicode version is supported by your JVM. A table of the Unicode versions up to JDK 17 can be found here. These parsers are only able to parse unicode characters in the range '\u0000' to '\uFFFF', known as the Basic Multilingual Plane (BMP). Unicode characters wider than a single 16-bit character should be parsed using multi-character combinators such as string, or, alternatively, satisfyUtf16 or charUtf16.

Whitespace Skipping Parsers

These parsers are designed to skip chunks of whitespace, for very rudimentary lexing tasks. It is probably better to use the functionality of parsley.token.

Character Predicates

These are useful for providing to the sub-descriptions of a token.descriptions.LexicalDesc to specify behaviour for the lexer. Other than that, they aren't particularly useful.

Packages

Package structure

character

object character

Value Members

Inherited from AnyRef

Inherited from Any

Core Combinators and Parsers

Character Class Combinators

String Combinators

Specific Character Parsers

Whitespace Skipping Parsers

Character Predicates

Ungrouped

Packages

Package structure

character

object character

Value Members

Inherited from AnyRef

Inherited from Any

Core Combinators and Parsers

Character Class Combinators

String Combinators

Specific Character Parsers

Whitespace Skipping Parsers

Character Predicates

Ungrouped

character