Scala Implicitly

“Everyone learning or adopting the Scala computer language eventually encounters the implicitly identifier. However, relatively few take the time to fully comprehend its significance. This guide will therefore analyze the semantics and main uses of the implicitly function. Implicitly functions essentially as a “compiler for implicits.” If a type “T” implicit value exists, we can confirm it. The compiler will notify us of the situation if there isn’t an implicit value of type “T” available in the scope. This is a useful option that we have to determine whether a specific type’s value is accessible in implicit scope.”

Syntax of Implicitly Keyword in Scala in Ubuntu 20.04

To construct explicit, concrete examples of types availability, a utility method is included in the Scala standard library. Additionally, implicit is the name of the method. Note that Scala version 2.8 introduces implicitly, which is described in Predef as:

def implicitly[T](implicit e: T) = e

Example # 1: Program of Implicitly Keyword Scala in Ubuntu 20.04

Here is a brief illustration from Retronyms’ presentation:

To the scala REPL mode, we have called the variable “x” with an implicit keyword and initialized it with the string. We have specified an implicit value of the typed string. The type is returned when the line of code is executed. After that, we searched for the typed string implicit value by passing it in the implicitly function and then assigned it to the “y” variable. The compiler returned the value of the string “demo” as it stored this value. Next, we found the implicit value of the “Int” type and set it inside the variable “z”. On compilation, it generates an error “could not find the implicit value for Int parameter”.

Example # 2: Program of Comprehending and Solving a Problem of Implicit Views in Scala in Ubuntu 20.04

When a selection’s prefix (for instance, the.prefix.selection(args) does not have a member selection applicable to args) is empty, an implicit view can be triggered (even after attempting to convert the arguments using the Implicit Views). When this happens, the compiler looks for implicit members that are either similar to implicit methods or Functions from a type with a selection that is declared, locally stated in the current, or scopes that are enclosed, inherited, or imported.

Here, we have passed the value “3” inside the 1.min() as “Int” has no definition of min. The result Int type generates the value “1”. Then, we have used the keyword implicitly to the Int, which has the min definition. It returned the implicit type “Int” as <function1>. After that, we have executed the res2(1), which will locate the implicit value present in the AnyRef definition. In the end, we used the .getClass method, which returned the scala.runtime.RichInt class.

Furthermore, when an expression deviates from the Expected Type, implicit views can be triggered, as shown below:

We have assigned the scala.runtime.RichInt statement to the value “1” which on execution provided the implicit value “1”

This function is required by the compiler in this case:

The scala.runtime.RichInt is then assigned to the Int type inside the implicitly function, and it gives the <function1> as output.

Example # 3: Program of Accessing a Context-Induced Implicit Parameter Scala in Ubuntu 20.04

Scala’s implicit parameters might even be more significant than its implicit views. They are type class pattern-compliant. This is utilized sporadically in the standard library; see Scala how the order is employed in SeqLike#sorted. Array manifests and CanBuildFrom objects are also passed using implicit parameters.

Context Bounds is a shortcut syntax that Scala 2.8 offers for implicit arguments. In a nutshell, a method that calls for an implicit input of type Y[X]

The implicit parameter is passed, but it is not named. When applying the method foo, exactly can this be useful? It is common for the implicit parameter to be sent through as an implicit parameter to another function that is called instead of having to be explicitly mentioned. To materialize the value, you can call implicitly while keeping the concise method definition with the Context Bound.

Example # 4: Program of Giving Explicit Input to a Portion of Implicit Parameters Scala in Ubuntu 20.04

Consider the following scenario when utilizing a type class-based approach and invoking a method that nicely prints a student detail:

We have defined the scala trait “display” which has the definition of the display as it takes the type “t” and assigns the value “1” to it. Then, we have created the object “display” where the implicit functions are established. The first implicit function is declared as “Intdisplay” which has the “Int” definition. This function is set with the new keyword for the display[Int], which will return the string representation.

Then, we established another implicit function as “Stringdisplay” for the string definition. Next, we have the function “MyStringdisplay” which has the toUpperCase for the conversion to upper case. After that, we constructed the case class “Student” and set its attributes “name” with the data type “String” and “age” with the type “Int”.

We have implemented the object “Student,” inside which the implicit “studentdisplay” function is defined. The function has assigned two variables, “di” for display integer and “ds” for the display of string. This implicit function has a nested function “display” which creates the object “s” for the “Student” class. The ds.display takes the input “” and the di.display takes the “s.age” parameter. Lastly, the variable “s” sets the values of the attributes “name” and “age” for class “Student”. With the implicitly function, we have displayed the “Student” values.

The scala REPL res6 displayed the results of the implicit values of class “Student” as follows:

What happens if we wish to alter how the name is the outcome? Although we can directly use Studentdisplay and supply a different display[String], we prefer to have the compiler pass the display[Int].

The following results are obtained if we employ the above piece of line in the preceding code.


In this post, we discussed the implicitly function, which has been a part of Scala since version 2.8. First, we began demonstrating the function’s fundamental role as a “compiler for implicit”. This implicitly method merely anticipates a type parameter, locates the implicit value present in scope, summons it, and gives it back to us. The extremely basic technique should be used implicitly for the following reasons.

About the author

Saeed Raza

Hello geeks! I am here to guide you about your tech-related issues. My expertise revolves around Linux, Databases & Programming. Additionally, I am practicing law in Pakistan. Cheers to all of you.