CODEWITHSUNDEEP
kotlinsequencedsl
lolo
lolo

Reputation: 5

Is sequence referred to internal DSL in Kotlin?

In book 'Kotlin in Action', it says Kotlin DSL structure is most commonly created through chained method calls. Also, a typical library consists of many methods and no context is maintained btw one call and the next.

I'm confused of which side sequence is close to. Before I read this, I've thought sequence is just API of library, but it really fits with feature of DSL.

Upvotes: 0

Views: 104

Answers (1)

Joffrey
Joffrey

Reputation: 37720

I'm not 100% sure this answers your question, but I would not think of Sequence pipelines as a "DSL" per se, in particular because it is quite general, which is the opposite of "domain-specific" - the heart of the definition of a DSL.

If you build your own builder API based on chained method calls for a specific domain, you could consider that as a DSL, but I would say Kotlin DSLs are mostly made of nested lambdas with declarative property assignments, rather than chained method calls.

This is because lambdas in Kotlin give the illusion of blocks and structure more than actual functions and function calls, which is why nested structures like this look like their own "language" (the L of DSL). Chained method calls don't look like another "language" - they just look like function calls, but of course that's my subjective take.

For example, here is a Gradle build script using the Gradle Kotlin DSL:

plugins {
    `java-library`
}

dependencies {                              
    api("junit:junit:4.13")
    implementation("junit:junit:4.13")
    testImplementation("junit:junit:4.13")
}

java {                                      
    sourceCompatibility = JavaVersion.VERSION_11
    targetCompatibility = JavaVersion.VERSION_11
}

It does look like its own language, you don't immediately think of Kotlin when reading such code.

Upvotes: 2

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