Understanding `Context.Tag` Constructor

One Question about this piece of code from the docs:

import { Effect, Context } from "effect"
 
export class Random extends Context.Tag("Random")<
  Random,
  { readonly next: Effect.Effect<number> }
>() {}

import { Effect, Context } from "effect"
 
export class Random extends Context.Tag("Random")<
  Random,
  { readonly next: Effect.Effect<number> }
>() {}

Is the whole

class Random

class Random

construct »only used« to create some sort of Symbol - which exists at runtime - that can be referenced right after as it's type? I mean, the class body is empty and

new Random()

new Random()

is never called, at least in the docs.

Would that be in any way semantically different than this:

type Time = symbol;
const Time = Context.Tag('Time')<Time, { now: Effect.Effect<number> }>()

type Time = symbol;
const Time = Context.Tag('Time')<Time, { now: Effect.Effect<number> }>()

Effect Community•2y ago

sign error

Understanding `Context.Tag` Constructor

One Question about this piece of code from the docs:

import { Effect, Context } from "effect"
 
export class Random extends Context.Tag("Random")<
  Random,
  { readonly next: Effect.Effect<number> }
>() {}

import { Effect, Context } from "effect"
 
export class Random extends Context.Tag("Random")<
  Random,
  { readonly next: Effect.Effect<number> }
>() {}

Is the whole

class Random

class Random

construct »only used« to create some sort of Symbol - which exists at runtime - that can be referenced right after as it's type? I mean, the class body is empty and

new Random()

new Random()

is never called, at least in the docs.

Would that be in any way semantically different than this:

type Time = symbol;
const Time = Context.Tag('Time')<Time, { now: Effect.Effect<number> }>()

type Time = symbol;
const Time = Context.Tag('Time')<Time, { now: Effect.Effect<number> }>()

Understanding `Context.Tag` Constructor

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