pedantic - v0.1.1

pedantic/decode

Types

Decoder

</>

A Decoder describes how to parse, coerce, and validate a dynamic input.

pub type Decoder(t) {
  Decoder(
    graph: report.TypeGraph,
    function: fn(dynamic.Dynamic) -> Result(t, report.Report),
  )
}

Constructors

ObjectBuilder

opaque </>

An intermediate builder structure used to construct record decoders.

pub opaque type ObjectBuilder(constructor, value)

Values

allow_chars

</> 
pub fn allow_chars(
  decoder: Decoder(String),
  characters: String,
) -> Decoder(String)

Keeps only graphemes contained in characters.

any_of

</> 
pub fn any_of(decoders: List(Decoder(t))) -> Decoder(t)

assert_that

</> 
pub fn assert_that(
  decoder: Decoder(t),
  predicate: fn(t) -> Bool,
  error: report.ErrorKind,
) -> Decoder(t)

Asserts validation constraints using a boolean predicate function.

bool

</> 
pub const bool: Decoder(Bool)

build

</> 
pub fn build(
  builder: ObjectBuilder(value, value),
) -> Decoder(value)

Finalizes the ObjectBuilder, converting it into a full Decoder.

check

</> 
pub fn check(
  decoder: Decoder(t),
  predicate: fn(t) -> Bool,
  msg: String,
) -> Decoder(t)

Standard check validator.

coerced_bool

</> 
pub const coerced_bool: Decoder(Bool)

Primitive Bool decoder with safe type coercion from Int or String.

coerced_float

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pub const coerced_float: Decoder(Float)

Primitive Float decoder with safe type coercion from Int or String.

coerced_int

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pub const coerced_int: Decoder(Int)

Primitive Int decoder with safe type coercion from String.

coerced_string

</> 
pub const coerced_string: Decoder(String)

Primitive String decoder with safe type coercion from Int, Float, or Bool.

collapse_whitespace

</> 
pub fn collapse_whitespace(
  decoder: Decoder(String),
) -> Decoder(String)

Replaces each run of whitespace with a single space and trims the result.

default

</> 
pub fn default(
  decoder: Decoder(option.Option(a)),
  default_val: a,
) -> Decoder(a)

Adapts an optional decoder with a default value fallback.

default_if_blank

</> 
pub fn default_if_blank(
  decoder: Decoder(String),
  default_value: String,
) -> Decoder(String)

Trims a string and replaces blank values with default_value.

default_to

</> 
pub const default_to: fn(Decoder(option.Option(a)), a) -> Decoder(
  a,
)

describe

</> 
pub fn describe(decoder: Decoder(t), desc: String) -> Decoder(t)

Sets the description metadata in the AST graph.

dict

</> 
pub fn dict(
  value_decoder: Decoder(a),
) -> Decoder(dict.Dict(String, a))

Dict combinator to decode dynamic objects with string keys, accumulating errors.

digits_only

</> 
pub fn digits_only(decoder: Decoder(String)) -> Decoder(String)

Keeps only ASCII digits from the string.

email

</> 
pub fn email(
  decoder: Decoder(String),
  msg: String,
) -> Decoder(String)

empty_as_none

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pub fn empty_as_none(
  decoder: Decoder(String),
) -> Decoder(option.Option(String))

Trims a string and turns blank values into None.

exact_bool

</> 
pub const exact_bool: Decoder(Bool)

Primitive Bool decoder verifying exact type without coercion.

exact_float

</> 
pub const exact_float: Decoder(Float)

Primitive Float decoder verifying exact type without coercion.

exact_int

</> 
pub const exact_int: Decoder(Int)

Primitive Int decoder verifying exact type without coercion.

exact_string

</> 
pub const exact_string: Decoder(String)

Primitive String decoder verifying exact type without coercion.

example

</> 
pub fn example(
  decoder: Decoder(t),
  ex: dynamic.Dynamic,
) -> Decoder(t)

Sets the example metadata in the AST graph.

field

</> 
pub fn field(
  builder: ObjectBuilder(fn(field_type) -> next, value),
  name: String,
  field_decoder: Decoder(field_type),
) -> ObjectBuilder(next, value)

Applies a field description and decoder to the object builder.

float

</> 
pub const float: Decoder(Float)

float_range

</> 
pub fn float_range(
  minimum: Float,
  maximum: Float,
) -> Decoder(Float)

int

</> 
pub const int: Decoder(Int)

int_range

</> 
pub fn int_range(minimum: Int, maximum: Int) -> Decoder(Int)

key

</> 
pub const key: fn(
  ObjectBuilder(fn(field_type) -> next, value),
  String,
  Decoder(field_type),
) -> ObjectBuilder(next, value)

key_optional

</> 
pub fn key_optional(
  builder: ObjectBuilder(
    fn(option.Option(field_type)) -> next,
    value,
  ),
  name: String,
  field_decoder: Decoder(field_type),
) -> ObjectBuilder(next, value)

Declares an optional key in the object builder, resolving to Option(t).

key_required

</> 
pub const key_required: fn(
  ObjectBuilder(fn(field_type) -> next, value),
  String,
  Decoder(field_type),
) -> ObjectBuilder(next, value)

key_with_default

</> 
pub fn key_with_default(
  builder: ObjectBuilder(fn(field_type) -> next, value),
  name: String,
  field_decoder: Decoder(field_type),
  default_val: field_type,
) -> ObjectBuilder(next, value)

Declares an optional key with fallback default value.

length

</> 
pub fn length(
  decoder: Decoder(String),
  len: Int,
) -> Decoder(String)

letters_only

</> 
pub fn letters_only(decoder: Decoder(String)) -> Decoder(String)

Keeps only ASCII letters from the string.

list

</> 
pub fn list(element_decoder: Decoder(a)) -> Decoder(List(a))

List combinator that decodes dynamic arrays into typed Lists, accumulating errors.

lowercase

</> 
pub fn lowercase(decoder: Decoder(String)) -> Decoder(String)

map

</> 
pub fn map(
  decoder: Decoder(a),
  transform_fn: fn(a) -> b,
) -> Decoder(b)

max

</> 
pub fn max(decoder: Decoder(Int), maximum: Int) -> Decoder(Int)

Restricts an Int decoder to values less than or equal to the maximum.

max_length

</> 
pub fn max_length(
  decoder: Decoder(String),
  maximum: Int,
) -> Decoder(String)

Restricts a String decoder to a maximum length.

max_size

</> 
pub fn max_size(
  decoder: Decoder(List(a)),
  maximum: Int,
) -> Decoder(List(a))

min

</> 
pub fn min(decoder: Decoder(Int), minimum: Int) -> Decoder(Int)

Restricts an Int decoder to values greater than or equal to the minimum.

min_length

</> 
pub fn min_length(
  decoder: Decoder(String),
  minimum: Int,
) -> Decoder(String)

Restricts a String decoder to a minimum length.

min_size

</> 
pub fn min_size(
  decoder: Decoder(List(a)),
  minimum: Int,
) -> Decoder(List(a))

negative

</> 
pub fn negative(decoder: Decoder(Int)) -> Decoder(Int)

non_empty_list

</> 
pub fn non_empty_list(
  element_decoder: Decoder(a),
) -> Decoder(List(a))

non_empty_string

</> 
pub const non_empty_string: Decoder(String)

non_negative

</> 
pub fn non_negative(decoder: Decoder(Int)) -> Decoder(Int)

non_positive

</> 
pub fn non_positive(decoder: Decoder(Int)) -> Decoder(Int)

normalize_email

</> 
pub fn normalize_email(
  decoder: Decoder(String),
) -> Decoder(String)

Trims and lowercases a string, useful for case-insensitive identifiers.

normalize_line_endings

</> 
pub fn normalize_line_endings(
  decoder: Decoder(String),
) -> Decoder(String)

Converts CRLF and CR line endings to LF line endings.

normalize_uuid

</> 
pub fn normalize_uuid(
  decoder: Decoder(String),
) -> Decoder(String)

Trims and lowercases a UUID string.

object

</> 
pub fn object(
  name: String,
  constructor: constructor,
) -> ObjectBuilder(constructor, value)

Initializes an ObjectBuilder for a custom record constructor.

optional

</> 
pub fn optional(
  inner_decoder: Decoder(a),
) -> Decoder(option.Option(a))

Option/Optional combinator representing absent or nullable values.

positive

</> 
pub fn positive(decoder: Decoder(Int)) -> Decoder(Int)

refine

</> 
pub fn refine(
  decoder: Decoder(t),
  rule: fn(t) -> Result(t, report.ErrorKind),
) -> Decoder(t)

Refines a decoder with a custom validation rule.

remove_chars

</> 
pub fn remove_chars(
  decoder: Decoder(String),
  characters: String,
) -> Decoder(String)

Removes every grapheme contained in characters.

remove_whitespace

</> 
pub fn remove_whitespace(
  decoder: Decoder(String),
) -> Decoder(String)

Removes spaces, tabs, newlines, carriage returns, and non-breaking spaces.

replace

</> 
pub fn replace(
  decoder: Decoder(String),
  pattern: String,
  replacement: String,
) -> Decoder(String)

Replaces every occurrence of pattern with replacement.

string

</> 
pub const string: Decoder(String)

string_limit

</> 
pub fn string_limit(
  minimum: Int,
  maximum: Int,
) -> Decoder(String)

strip_control_chars

</> 
pub fn strip_control_chars(
  decoder: Decoder(String),
) -> Decoder(String)

Removes Unicode control code points from the string.

strip_non_ascii

</> 
pub fn strip_non_ascii(
  decoder: Decoder(String),
) -> Decoder(String)

Removes all non-ASCII Unicode code points.

title

</> 
pub fn title(decoder: Decoder(t), name: String) -> Decoder(t)

Sets the title metadata in the AST graph.

trim

</> 
pub fn trim(decoder: Decoder(String)) -> Decoder(String)

unwrap_or

</> 
pub const unwrap_or: fn(Decoder(option.Option(a)), a) -> Decoder(
  a,
)

uppercase

</> 
pub fn uppercase(decoder: Decoder(String)) -> Decoder(String)

uuid

</> 
pub fn uuid(
  decoder: Decoder(String),
  msg: String,
) -> Decoder(String)

with_error_formatter

</> 
pub fn with_error_formatter(
  decoder: Decoder(t),
  formatter: fn(dynamic.Dynamic, report.ErrorKind) -> String,
) -> Decoder(t)

Custom error formatter decorator.

with_error_message

</> 
pub fn with_error_message(
  decoder: Decoder(t),
  msg: String,
) -> Decoder(t)

Exposes simple custom validation string messages.

with_template

</> 
pub fn with_template(
  decoder: Decoder(t),
  template: String,
) -> Decoder(t)

Placeholder template parser replacing {value}, {min}, {max}, {length}.

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