This page goes through Kotlin’s documentation topic by topic and shows how to do each thing in Romit, or says plainly that Romit doesn’t.
Romit isn’t trying to be Kotlin. It has no classes, generics or static types, because those work against “write it like a prompt”. It does aim to cover what everyday programs need, and its app layer overlaps with Compose Multiplatform .
Status: ✅ supported · 🟡 partly or another way · ❌ missing · ➖ doesn’t apply to Romit’s design
Kotlin Romit
val / varx = 5, set x to 5 (no read-only values)🟡 Operators symbols and words (+ / plus, >= / is at least) ✅ String templates "$x ${a.b}" "{x} {a.b}", any expression inside, quotes allowed✅ Raw and multi-line strings """…""" (indentation trimmed), escapes \n \t \" \\✅ String functions upper, lower, trim, split, join, replace … with … in, starts with, ends with, contains, letters 1 to 3 of, length✅ Numbers whole numbers and decimals, 7 / 2 = 3.5, 1_000; no Byte/Float/hex literals 🟡 Booleans true / false✅ Characters single letters are text (item 2 of "hi") 🟡 Arrays and lists list a, b, add, remove, item n of, first/last N of, items a to b of✅ Maps map "a" to 1, item k of m, set item k of m to v, keys of, values of, contains✅ Sets unique of xs🟡 Ranges 1 to 5, 10 to 1 (down), by 2 (step), range 1, 5✅ Null safety (?, ?:, ?.) nothing, is nothing, or else; a missing field gives nothing✅ Type checks and casts no static types; number of, text of convert ➖ Unsigned types, type aliases — ➖ Packages and imports use "file.rmt" (scripts and apps)✅ Annotations, visibility modifiers — ➖
Kotlin Romit
if / else (also as an expression)if / otherwise if / otherwise; if … then … else …✅ whenmatch with values, comparisons, or no subject✅ for, whilefor each x in xs, for each i in 1 to 9 by 2, while✅ do-whilewhile with stop🟡 return, break, continuegive, stop, skip (no labels)✅ Exceptions: throw, try / catch fail "…", try … if it fails (error holds the message)✅ finally— ❌ Functions, defaults, named arguments, recursion fn name a, b, b is 2, with b 3, recursion✅ Top-level properties functions can read top-level values ✅ Varargs, local functions, return types — ❌ Lambdas and higher-order functions where, each, sorted by take an expression with it; apps pass actions (do …, on tap); no lambda values🟡 Type-safe builders (DSLs) the app syntax is a builder DSL like Compose 🟡 Inline functions, operator overloading, context parameters, extensions — ➖ Reading input readln() ask "Question?"✅
Kotlin Romit
Data classes records: with name "Ada", age 36, field access and change, structural equality, readable printing ✅ Destructuring — ❌ Enum classes, entries enum Size small, medium, large; Size lists the values✅ Sealed classes spec machine (allowed state changes checked by the compiler) 🟡 object (singletons)an app’s state is one shared object 🟡 Properties, getters, observers app state, computed, on change of x, saved (persisted) 🟡 Classes, inheritance, interfaces, generics, delegation — ➖
Kotlin Romit
Filter, map, sort, group where, each, sorted by … descending, grouped by✅ Aggregate count, sum, average, min, max✅ Take, drop, slice, first, last first N of, last N of, items a to b of, first of, last of✅ zip, flatMap, windowed— ❌ Scope functions, sequences, reflection — ➖ Date and time today, now, year / month / day / weekday of, days from a to b; apps: as date, as ago, date picker🟡 JSON (kotlinx.serialization) automatic: saved, load "url" into x, open file … as json, save x to file 🟡 HTTP client (Ktor client) load "https://…" into x (GET)🟡 Coroutines apps: async actions (wait, load), timers (every), reactive state; no channels or flows 🟡 Testing (kotlin.test) spec test blocks with romit test 🟡 UUIDs, HTTP server, databases — ❌
Kotlin Romit
Compose Multiplatform + Material 3 Romit apps : Material 3 on Android, Apple style on iPhone✅ Kotlin/JS, web apps compile to one HTML file ✅ Android, iOS apps run in the phone’s browser with a native look; no store builds 🟡 JVM, Native, Wasm targets, Java/C/Swift interop — ❌ Scripting (.kts) romit run script.rmt✅ IDE support VS Code extension: highlighting, errors as you type, autocomplete, snippets, run command 🟡 Gradle / Maven one romit tool ➖
See also: SwiftUI → Romit , Records, match, and errors .