postgleam - v0.8.0

postgleam/decode

Types

RowDecoder

opaque </>

A decoder that extracts a typed value from a row (list of columns).

pub opaque type RowDecoder(a)

ValueDecoder

</>

A decoder that extracts a typed value from a single cell.

pub type ValueDecoder(a) =
  fn(option.Option(value.Value)) -> Result(a, error.Error)

Values

bit_string

</> 
pub fn bit_string(
  val: option.Option(value.Value),
) -> Result(#(Int, BitArray), error.Error)

Decode a bit/varbit value as #(bit_count, data).

bool

</> 
pub fn bool(
  val: option.Option(value.Value),
) -> Result(Bool, error.Error)

Decode a boolean value.

box

</> 
pub fn box(
  val: option.Option(value.Value),
) -> Result(#(Float, Float, Float, Float), error.Error)

Decode a box as #(x1, y1, x2, y2) (upper-right, lower-left).

bytea

</> 
pub fn bytea(
  val: option.Option(value.Value),
) -> Result(BitArray, error.Error)

Decode a bytea (binary data) value.

circle

</> 
pub fn circle(
  val: option.Option(value.Value),
) -> Result(#(Float, Float, Float), error.Error)

Decode a circle as #(x, y, radius).

date

</> 
pub fn date(
  val: option.Option(value.Value),
) -> Result(Int, error.Error)

Decode a date value (days since 2000-01-01).

element

</> 
pub fn element(
  index: Int,
  decoder: fn(option.Option(value.Value)) -> Result(
    a,
    error.Error,
  ),
  next: fn(a) -> RowDecoder(b),
) -> RowDecoder(b)

Decode the element at a given column index using a value decoder. Designed for use with Gleam’s use syntax.

let decoder = {
  use id <- decode.element(0, decode.int)
  use name <- decode.element(1, decode.text)
  decode.success(#(id, name))
}

float

</> 
pub fn float(
  val: option.Option(value.Value),
) -> Result(Float, error.Error)

Decode a float value (float4, float8).

inet

</> 
pub fn inet(
  val: option.Option(value.Value),
) -> Result(#(Int, BitArray, Int), error.Error)

Decode an inet/cidr value as #(family, address, netmask).

int

</> 
pub fn int(
  val: option.Option(value.Value),
) -> Result(Int, error.Error)

Decode an integer value (int2, int4, int8).

interval

</> 
pub fn interval(
  val: option.Option(value.Value),
) -> Result(#(Int, Int, Int), error.Error)

Decode an interval value as #(microseconds, days, months).

json

</> 
pub fn json(
  val: option.Option(value.Value),
) -> Result(String, error.Error)

Decode a JSON value (string).

jsonb

</> 
pub fn jsonb(
  val: option.Option(value.Value),
) -> Result(String, error.Error)

Decode a JSONB value (string).

jsonpath

</> 
pub fn jsonpath(
  val: option.Option(value.Value),
) -> Result(String, error.Error)

Decode a JSONPath value (string).

line

</> 
pub fn line(
  val: option.Option(value.Value),
) -> Result(#(Float, Float, Float), error.Error)

Decode a line value as #(a, b, c) coefficients.

lseg

</> 
pub fn lseg(
  val: option.Option(value.Value),
) -> Result(#(Float, Float, Float, Float), error.Error)

Decode a line segment as #(x1, y1, x2, y2).

macaddr

</> 
pub fn macaddr(
  val: option.Option(value.Value),
) -> Result(BitArray, error.Error)

Decode a macaddr value (6-byte binary).

macaddr8

</> 
pub fn macaddr8(
  val: option.Option(value.Value),
) -> Result(BitArray, error.Error)

Decode a macaddr8 value (8-byte binary).

money

</> 
pub fn money(
  val: option.Option(value.Value),
) -> Result(Int, error.Error)

Decode a money value (int64 cents).

numeric

</> 
pub fn numeric(
  val: option.Option(value.Value),
) -> Result(String, error.Error)

Decode a numeric/decimal value (string representation).

optional

</> 
pub fn optional(
  decoder: fn(option.Option(value.Value)) -> Result(
    a,
    error.Error,
  ),
) -> fn(option.Option(value.Value)) -> Result(
  option.Option(a),
  error.Error,
)

Make any value decoder nullable (NULL-safe). Returns Ok(None) for NULL, Ok(Some(val)) for non-NULL.

path

</> 
pub fn path(
  val: option.Option(value.Value),
) -> Result(#(Bool, List(#(Float, Float))), error.Error)

Decode a path as #(closed, points).

point

</> 
pub fn point(
  val: option.Option(value.Value),
) -> Result(#(Float, Float), error.Error)

Decode a point value as #(x, y).

polygon

</> 
pub fn polygon(
  val: option.Option(value.Value),
) -> Result(List(#(Float, Float)), error.Error)

Decode a polygon as a list of vertices.

run

</> 
pub fn run(
  decoder: RowDecoder(a),
  row: List(option.Option(value.Value)),
) -> Result(a, error.Error)

Run a decoder on a row.

success

</> 
pub fn success(value: a) -> RowDecoder(a)

Finalize a decoder chain with a value.

text

</> 
pub fn text(
  val: option.Option(value.Value),
) -> Result(String, error.Error)

Decode a text/string value. Also coerces UUID and Boolean values to their string representation, since sqlc’s uuidAsString option and any pseudotype generate decode.text for columns that PostgreSQL returns as UUID or Bool.

time

</> 
pub fn time(
  val: option.Option(value.Value),
) -> Result(Int, error.Error)

Decode a time value (microseconds since midnight).

timestamp

</> 
pub fn timestamp(
  val: option.Option(value.Value),
) -> Result(Int, error.Error)

Decode a timestamp value (microseconds since 2000-01-01 00:00:00).

timestamptz

</> 
pub fn timestamptz(
  val: option.Option(value.Value),
) -> Result(Int, error.Error)

Decode a timestamptz value (microseconds since 2000-01-01 00:00:00 UTC).

timetz

</> 
pub fn timetz(
  val: option.Option(value.Value),
) -> Result(#(Int, Int), error.Error)

Decode a timetz value as #(microseconds, tz_offset_seconds).

uuid

</> 
pub fn uuid(
  val: option.Option(value.Value),
) -> Result(BitArray, error.Error)

Decode a UUID value (16-byte binary).

uuid_string

</> 
pub fn uuid_string(
  val: option.Option(value.Value),
) -> Result(String, error.Error)

Decode a UUID value as a hyphenated string (e.g. “550e8400-e29b-41d4-a716-446655440000”).

xml

</> 
pub fn xml(
  val: option.Option(value.Value),
) -> Result(String, error.Error)

Decode an XML value (string).

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