Overview

This page gives a high-level overview of core standard library abstractions.

Modules in this section

• io — console and stream-style input/output helpers
• collections — list and collection transforms
• string — UTF-8 string utilities
• option — optional-value helpers
• result — success/error composition helpers
• math — numeric utilities
• sequence — lazy/iterable sequence helpers
• iter — generic Iter(a)-based helpers

Core abstractions

• seq(a) for finite sequences
• gen(a) for potentially infinite sequences
• list(a) for indexed lists
• set(a) for membership checks
• map(k, v) for key/value lookup
• lookup(k, v) for multi-value lookups

Async collections

• stream(a) for async streams
• async(a) for async computations

Option and result

There is no Option type. Any union containing #some(a) is option-like by convention, and the option module’s helpers work on all of them; #some(a) | #none is simply the most common shape.

The Result alias exists for the equally common success/error shape:

type Result(a, e) = #some(a) | #error(e)

Map literals

Maps are written with the square-bracket literal syntax and the => operator:

def myMap = ["hello" => "world", "foo" => "bar"]

Square-bracket literals desugar to a call to the target type’s builder, which is what makes the same syntax work for lists, sets and maps. See Collections.

If you want more detail, visit the specific module pages in this section.