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Class scala.StringContext

case class StringContext(parts: String*) extends Product with Serializable

This class provides the basic mechanism to do String Interpolation. String Interpolation allows users to embed variable references directly in *processed* string literals. Here's an example:

val name = "James"
println(s"Hello, $name")  // Hello, James

Any processed string literal is rewritten as an instantiation and method call against this class. For example:

s"Hello, $name"

is rewritten to be:

StringContext("Hello, ", "").s(name)

By default, this class provides the raw, s and f methods as available interpolators.

To provide your own string interpolator, create an implicit class which adds a method to StringContext. Here's an example:

implicit class JsonHelper(private val sc: StringContext) extends AnyVal {
  def json(args: Any*): JSONObject = ...
}
val x: JSONObject = json"{ a: $a }"

Here the JsonHelper extension class implicitly adds the json method to StringContext which can be used for json string literals.

parts

The parts that make up the interpolated string, without the expressions that get inserted by interpolation.

Source
StringContext.scala
Since

2.10.0

Linear Supertypes

Instance Constructors

new StringContext(parts: String*)

parts

The parts that make up the interpolated string, without the expressions that get inserted by interpolation.

Value Members

final def !=(arg0: Any): Boolean

Test two objects for inequality.

returns

true if !(this == that), false otherwise.

Definition Classes
AnyRef → Any

final def ##(): Int

Equivalent to x.hashCode except for boxed numeric types and null. For numerics, it returns a hash value which is consistent with value equality: if two value type instances compare as true, then ## will produce the same hash value for each of them. For null returns a hashcode where null.hashCode throws a NullPointerException.

returns

a hash value consistent with ==

Definition Classes
AnyRef → Any

def +(other: String): String

Implicit
This member is added by an implicit conversion from StringContext to any2stringadd[StringContext] performed by method any2stringadd in scala.Predef.
Definition Classes
any2stringadd

def ->[B](y: B): (StringContext, B)

Implicit
This member is added by an implicit conversion from StringContext to ArrowAssoc[StringContext] performed by method ArrowAssoc in scala.Predef.
Definition Classes
ArrowAssoc
Annotations
@inline()

final def ==(arg0: Any): Boolean

The expression x == that is equivalent to if (x eq null) that eq null else x.equals(that).

returns

true if the receiver object is equivalent to the argument; false otherwise.

Definition Classes
AnyRef → Any

final def asInstanceOf[T0]: T0

Cast the receiver object to be of type T0.

Note that the success of a cast at runtime is modulo Scala's erasure semantics. Therefore the expression 1.asInstanceOf[String] will throw a ClassCastException at runtime, while the expression List(1).asInstanceOf[List[String]] will not. In the latter example, because the type argument is erased as part of compilation it is not possible to check whether the contents of the list are of the requested type.

returns

the receiver object.

Definition Classes
Any
Exceptions thrown

ClassCastException if the receiver object is not an instance of the erasure of type T0.

def checkLengths(args: Seq[Any]): Unit

Checks that the length of the given argument args is one less than the number of parts supplied to the enclosing StringContext.

Exceptions thrown

IllegalArgumentException if this is not the case.

def clone(): AnyRef

Create a copy of the receiver object.

The default implementation of the clone method is platform dependent.

returns

a copy of the receiver object.

Attributes
protected[lang]
Definition Classes
AnyRef
Annotations
@throws( ... ) @native()
Note

not specified by SLS as a member of AnyRef

def ensuring(cond: (StringContext) ⇒ Boolean, msg: ⇒ Any): StringContext

Implicit
This member is added by an implicit conversion from StringContext to Ensuring[StringContext] performed by method Ensuring in scala.Predef.
Definition Classes
Ensuring

def ensuring(cond: (StringContext) ⇒ Boolean): StringContext

Implicit
This member is added by an implicit conversion from StringContext to Ensuring[StringContext] performed by method Ensuring in scala.Predef.
Definition Classes
Ensuring

def ensuring(cond: Boolean, msg: ⇒ Any): StringContext

Implicit
This member is added by an implicit conversion from StringContext to Ensuring[StringContext] performed by method Ensuring in scala.Predef.
Definition Classes
Ensuring

def ensuring(cond: Boolean): StringContext

Implicit
This member is added by an implicit conversion from StringContext to Ensuring[StringContext] performed by method Ensuring in scala.Predef.
Definition Classes
Ensuring

final def eq(arg0: AnyRef): Boolean

Tests whether the argument (that) is a reference to the receiver object (this).

The eq method implements an equivalence relation on non-null instances of AnyRef, and has three additional properties:

    It is consistent: for any non-null instances x and y of type AnyRef, multiple invocations of x.eq(y) consistently returns true or consistently returns false.For any non-null instance x of type AnyRef, x.eq(null) and null.eq(x) returns false. null.eq(null) returns true.

When overriding the equals or hashCode methods, it is important to ensure that their behavior is consistent with reference equality. Therefore, if two objects are references to each other (o1 eq o2), they should be equal to each other (o1 == o2) and they should hash to the same value (o1.hashCode == o2.hashCode).

returns

true if the argument is a reference to the receiver object; false otherwise.

Definition Classes
AnyRef

macro def f[A >: Any](args: A*): String

The formatted string interpolator.

It inserts its arguments between corresponding parts of the string context. It also treats standard escape sequences as defined in the Scala specification. Finally, if an interpolated expression is followed by a parts string that starts with a formatting specifier, the expression is formatted according to that specifier. All specifiers allowed in Java format strings are handled, and in the same way they are treated in Java.

For example:

val height = 1.9d
val name = "James"
println(f"$name%s is $height%2.2f meters tall")  // James is 1.90 meters tall
Exceptions thrown

IllegalArgumentException if the number of parts in the enclosing StringContext does not exceed the number of arguments arg by exactly 1.

if a parts string contains a backslash (\) character that does not start a valid escape sequence. Note: The f method works by assembling a format string from all the parts strings and using java.lang.String.format to format all arguments with that format string. The format string is obtained by concatenating all parts strings, and performing two transformations:

    Let a _formatting position_ be a start of any parts string except the first one. If a formatting position does not refer to a % character (which is assumed to start a format specifier), then the string format specifier %s is inserted. 2. Any % characters not in formatting positions must begin one of the conversions %% (the literal percent) or %n (the platform-specific line separator).

def finalize(): Unit

Called by the garbage collector on the receiver object when there are no more references to the object.

The details of when and if the finalize method is invoked, as well as the interaction between finalize and non-local returns and exceptions, are all platform dependent.

Attributes
protected[lang]
Definition Classes
AnyRef
Annotations
@throws( classOf[java.lang.Throwable] )
Note

not specified by SLS as a member of AnyRef

def formatted(fmtstr: String): String

Returns string formatted according to given format string. Format strings are as for String.format (@see java.lang.String.format).

Implicit
This member is added by an implicit conversion from StringContext to StringFormat[StringContext] performed by method StringFormat in scala.Predef.
Definition Classes
StringFormat
Annotations
@inline()

final def getClass(): Class[_]

Returns the runtime class representation of the object.

returns

a class object corresponding to the runtime type of the receiver.

Definition Classes
AnyRef → Any
Annotations
@native()

final def isInstanceOf[T0]: Boolean

Test whether the dynamic type of the receiver object is T0.

Note that the result of the test is modulo Scala's erasure semantics. Therefore the expression 1.isInstanceOf[String] will return false, while the expression List(1).isInstanceOf[List[String]] will return true. In the latter example, because the type argument is erased as part of compilation it is not possible to check whether the contents of the list are of the specified type.

returns

true if the receiver object is an instance of erasure of type T0; false otherwise.

Definition Classes
Any

final def ne(arg0: AnyRef): Boolean

Equivalent to !(this eq that).

returns

true if the argument is not a reference to the receiver object; false otherwise.

Definition Classes
AnyRef

final def notify(): Unit

Wakes up a single thread that is waiting on the receiver object's monitor.

Definition Classes
AnyRef
Annotations
@native()
Note

not specified by SLS as a member of AnyRef

final def notifyAll(): Unit

Wakes up all threads that are waiting on the receiver object's monitor.

Definition Classes
AnyRef
Annotations
@native()
Note

not specified by SLS as a member of AnyRef

val parts: String*

def raw(args: Any*): String

The raw string interpolator.

It inserts its arguments between corresponding parts of the string context. As opposed to the simple string interpolator s, this one does not treat standard escape sequences as defined in the Scala specification.

For example, the raw processed string raw"a\nb" is equal to the scala string "a\\nb".

Note: Even when using the raw interpolator, Scala will preprocess unicode escapes. For example:

scala> raw"\u0023"
res0: String = #
Exceptions thrown

IllegalArgumentException if the number of parts in the enclosing StringContext does not exceed the number of arguments arg by exactly 1.

Note

The Scala compiler may replace a call to this method with an equivalent, but more efficient, use of a StringBuilder.

def s(args: Any*): String

The simple string interpolator.

It inserts its arguments between corresponding parts of the string context. It also treats standard escape sequences as defined in the Scala specification. Here's an example of usage:

val name = "James"
println(s"Hello, $name")  // Hello, James

In this example, the expression $name is replaced with the toString of the variable name. The s interpolator can take the toString of any arbitrary expression within a ${} block, for example:

println(s"1 + 1 = ${1 + 1}")

will print the string 1 + 1 = 2.

Exceptions thrown

IllegalArgumentException if the number of parts in the enclosing StringContext does not exceed the number of arguments arg by exactly 1.

StringContext.InvalidEscapeException if a parts string contains a backslash (\) character that does not start a valid escape sequence.

Note

The Scala compiler may replace a call to this method with an equivalent, but more efficient, use of a StringBuilder.

def standardInterpolator(process: (String) ⇒ String, args: Seq[Any]): String

final def synchronized[T0](arg0: ⇒ T0): T0

Definition Classes
AnyRef

final def wait(): Unit

Definition Classes
AnyRef
Annotations
@throws( ... )

final def wait(arg0: Long, arg1: Int): Unit

Definition Classes
AnyRef
Annotations
@throws( ... )

final def wait(arg0: Long): Unit

Definition Classes
AnyRef
Annotations
@throws( ... ) @native()

def [B](y: B): (StringContext, B)

Implicit
This member is added by an implicit conversion from StringContext to ArrowAssoc[StringContext] performed by method ArrowAssoc in scala.Predef.
Definition Classes
ArrowAssoc

© 2002-2019 EPFL, with contributions from Lightbend.
Licensed under the Apache License, Version 2.0.
https://www.scala-lang.org/api/2.12.9/scala/StringContext.html