dream_ets - v2.0.0

dream_ets/encoders

Built-in encoders and decoders for common types

This module provides pre-built encoder and decoder functions for Gleam’s primitive types. These functions handle the conversion between Gleam types and Erlang’s dynamic types for ETS storage.

Quick Start

import dream_ets/config
import dream_ets/encoders

// Use convenience functions (recommended)
let assert Ok(table) = config.new("cache")
  |> config.key_string()
  |> config.value_string()
  |> config.create()

// Or use encoders directly for custom configuration
let assert Ok(table) = config.new("scores")
  |> config.key(encoders.string_encoder, encoders.string_decoder())
  |> config.value(encoders.int_encoder, encoders.int_decoder())
  |> config.create()

Built-in Types

This module provides encoders/decoders for:

Custom Types

For complex or custom types, you’ll need to write your own encoders/decoders. Common patterns:

JSON Encoding

import gleam/json
import gleam/dynamic
import gleam/result

pub type User {
  User(name: String, age: Int)
}

fn encode_user(user: User) -> dynamic.Dynamic {
  json.object([
    #("name", json.string(user.name)),
    #("age", json.int(user.age)),
  ])
  |> json.to_string
  |> dynamic.from
}

fn decode_user() -> decode.Decoder(User) {
  use json_str <- decode.string
  use obj <- decode.then(json.decode(json_str, decode.dynamic))
  decode.decode2(
    User,
    decode.field("name", decode.string),
    decode.field("age", decode.int),
  )(obj)
}

Tuple Encoding

import gleam/dynamic

pub type Point {
  Point(x: Int, y: Int)
}

fn encode_point(p: Point) -> dynamic.Dynamic {
  dynamic.from(#(p.x, p.y))
}

fn decode_point() -> decode.Decoder(Point) {
  decode.decode2(
    Point,
    decode.element(0, decode.int),
    decode.element(1, decode.int),
  )
}

Values

bool_decoder

</> 
pub fn bool_decoder() -> decode.Decoder(Bool)

Decode a boolean from Dynamic

Converts an Erlang dynamic type back to a Gleam Bool.

Returns

A decoder that converts Dynamic values to Bool.

Example

import dream_ets/config
import dream_ets/encoders

let assert Ok(flags) = config.new("flags")
  |> config.key_string()
  |> config.value(encoders.bool_encoder, encoders.bool_decoder())
  |> config.create()

See Also

  • bool_encoder() - Encode booleans for storage

bool_encoder

</> 
pub fn bool_encoder(b: Bool) -> dynamic.Dynamic

Encode a boolean to Dynamic

Converts a Gleam Bool to Erlang’s dynamic type for storage in ETS.

Parameters

  • b: The boolean to encode

Returns

A Dynamic value representing the boolean.

Example

import dream_ets/config
import dream_ets/encoders

// Feature flags table
let assert Ok(flags) = config.new("feature_flags")
  |> config.key_string()
  |> config.value(encoders.bool_encoder, encoders.bool_decoder())
  |> config.create()

See Also

  • bool_decoder() - Decode booleans from storage

float_decoder

</> 
pub fn float_decoder() -> decode.Decoder(Float)

Decode a float from Dynamic

Converts an Erlang dynamic type back to a Gleam Float.

Returns

A decoder that converts Dynamic values to Float.

Example

import dream_ets/config
import dream_ets/encoders

let assert Ok(metrics) = config.new("latency")
  |> config.key_string()
  |> config.value(encoders.float_encoder, encoders.float_decoder())
  |> config.create()

See Also

  • float_encoder() - Encode floats for storage

float_encoder

</> 
pub fn float_encoder(f: Float) -> dynamic.Dynamic

Encode a float to Dynamic

Converts a Gleam Float to Erlang’s dynamic type for storage in ETS.

Parameters

  • f: The float to encode

Returns

A Dynamic value representing the float.

Example

import dream_ets/config
import dream_ets/encoders

// Prices table with float values
let assert Ok(prices) = config.new("product_prices")
  |> config.key_string()
  |> config.value(encoders.float_encoder, encoders.float_decoder())
  |> config.create()

See Also

  • float_decoder() - Decode floats from storage

int_decoder

</> 
pub fn int_decoder() -> decode.Decoder(Int)

Decode an integer from Dynamic

Converts an Erlang dynamic type back to a Gleam Int.

Returns

A decoder that converts Dynamic values to Int.

Example

import dream_ets/config
import dream_ets/encoders

let assert Ok(table) = config.new("scores")
  |> config.key_string()
  |> config.value(encoders.int_encoder, encoders.int_decoder())
  |> config.create()

See Also

  • int_encoder() - Encode integers for storage

int_encoder

</> 
pub fn int_encoder(i: Int) -> dynamic.Dynamic

Encode an integer to Dynamic

Converts a Gleam Int to Erlang’s dynamic type for storage in ETS.

Parameters

  • i: The integer to encode

Returns

A Dynamic value representing the integer.

Example

import dream_ets/config
import dream_ets/encoders

// Counter table with int values
let assert Ok(counter) = config.new("counts")
  |> config.key_string()
  |> config.value(encoders.int_encoder, encoders.int_decoder())
  |> config.create()

See Also

  • int_decoder() - Decode integers from storage
  • config.counter() - Convenience for counter tables

string_decoder

</> 
pub fn string_decoder() -> decode.Decoder(String)

Decode a string from Dynamic

Converts an Erlang dynamic type back to a Gleam String.

Returns

A decoder that converts Dynamic values to String.

Example

import dream_ets/config
import dream_ets/encoders

let assert Ok(table) = config.new("users")
  |> config.key_string()
  |> config.value(encoders.string_encoder, encoders.string_decoder())
  |> config.create()

See Also

  • string_encoder() - Encode strings for storage
  • config.value_string() - Convenience function for string values

string_encoder

</> 
pub fn string_encoder(s: String) -> dynamic.Dynamic

Encode a string to Dynamic

Converts a Gleam String to Erlang’s dynamic type for storage in ETS.

Parameters

  • s: The string to encode

Returns

A Dynamic value representing the string.

Example

import dream_ets/config
import dream_ets/encoders

let assert Ok(table) = config.new("cache")
  |> config.key(encoders.string_encoder, encoders.string_decoder())
  |> config.value_string()
  |> config.create()

See Also

  • string_decoder() - Decode strings from storage
  • config.key_string() - Convenience function for string keys
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