The expression ` 1 10 step 2 ` returns an IntProgression ` a kotlinlang #stdlib

Channels

100daysofkotlin

100daysofkotlin-2021

algolialibraries

android-architecture

android-databinding

androidgithubprojects

androidx-xprocessing

arrow-contributors

beepiz-libraries

cincinnati-user-group

codemash-precompiler

codingconventions

competitive-programming

competitivecoding

compose-android

compose-desktop

compose-ui-showcase

connect-audit-events

cscenter-course-2016

domain-driven-design

effective-kotlin

effectivekotlin

embedded-kotlin

event21-community-content

fb-internal-demo

fluid-libraries

framework-elide

getting-started

github-workflows-kt

graviton-browser

image-processing

intellij-plugins

intellij-tricks

introduce-yourself

java-to-kotlin-refactoring

jhipster-kotlin

jvm-ir-backend-feedback

k2-early-adopters

kotest-contributors

kotlin-by-example

kotlin-data-storage

kotlin-foundation

kotlin-in-action

kotlin-multiplatform-contest

kotlin-pakistan

kotlinforbeginners

kotlingforbeginners

kotlinprogrammers

kotlintest-devs

kotlinultimatechallenge

kotlinx-datetime

lambdaworld_cadiz

language-evolution

language-proposals

leedskotlinusergroup

library-development

machinelearningbawas

myndocs-oauth2-server

navigation-architecture-component

ohio-kotlin-users

pattern-matching

pocketgitclient

practical-functional-programming

prozis-android-backup

python-contributors

realworldkotlin

refactoring-to-kotlin

refreshversions

russian-kotlinasfirst

skia-wasm-interop-temp

sofl-user-group

spring-security

squarelibraries

stayhungrystayfoolish

strife-discord-lib

swagger-gradle-codegen

swiss-user-group

tricity-kotlin-user-group

Title

n

natpryce

02/07/2023, 10:40 PM

The expression

(1 .. 10 step 2)

returns an IntProgression,

('a' .. 'z' step 2)

returns a CharProgression, and there are equivalents for many built in types, but not for user-defined types. Could the stdlib define the

step

function for

ClosedRange<T>

, to return a new stdlib type

Progression<T>

.?

s

Sam

02/08/2023, 8:01 AM

Not every comparable can be added and subtracted, so it only really works for numeric types. What would step mean for e.g. a

String

? Unless it could take a lambda, like

generateSequence

...

infix fun ClosedRange<String>.step(step: (String) -> String): Iterable<String> =
    generateSequence(start, step).takeWhile { it in this }.asIterable()

for (s in "foo".."foooooo" step { it + "o" }) println(s)

I kind of like it! 😄

not entirely sure how sensible it is, though…

n

natpryce

02/08/2023, 12:54 PM

I kind of like it too!

But yeah, I get your point. There is no way to express “addable” in Kotlin.

But a step function is a good compromise

5 Views

#stdlib Join Slack