Guarded Struct Derive

Derive ops

Reference: usage-rules/derive.md.

Grammar

"sanitize(<op>, <op>, ...) validate(<op>, <op>, ...)"

Each op is an atom or atom=operand. The string is parsed at compile time into __derive_ops__: %{sanitize: [op, ...], validate: [op, ...]}. Operands like enum=String[a::b::c] are pre-evaluated at compile time into structured tuples ({:enum, ["a", "b", "c"]}).

Built-in op atoms

Live source of truth: lib/guarded_struct/derive/registry.ex. Current set:

Sanitize: :trim, :upcase, :downcase, :capitalize, :basic_html, :html5, :markdown_html, :strip_tags, :tag, :string_float, :string_integer.

Validate (types): :string, :integer, :float, :number, :list, :map, :tuple, :atom, :boolean, :bitstring, :struct, :exception, :function, :pid, :port, :reference, :nil_value, :not_nil_value.

Validate (content/format): :not_empty, :not_empty_string, :not_flatten_empty, :not_flatten_empty_item, :queue, :max_len, :min_len, :url, :tell, :geo_url, :email, :email_r, :location, :string_boolean, :datetime, :range, :date, :regex, :ipv4, :uuid, :username, :full_name, :enum, :equal, :custom, :either, :record, :string_float, :string_integer, :some_string_float, :some_string_integer.

Pipe-friendly direct API

alias GuardedStruct.Derive.SanitizerDerive
"  Alice@X.IO  " |> SanitizerDerive.sanitize(:trim) |> SanitizerDerive.sanitize(:downcase)
# => "alice@x.io"

The arg order is (value, op). The same convention extends to Extension.dispatch_sanitize(input, op) and to user-defined extension sanitizer callbacks (__sanitize__(input, op)).

Five accepted input syntaxes

All normalize to the same internal op map:

# 1. String (canonical)
field :x, :string, derives: "sanitize(trim) validate(string)"

# 2. @derives decorator
@derives "sanitize(trim) validate(string)"
field :x, :string

# 3. Keyword form
field :x, :string, derive: [sanitize: [:trim], validate: [:string]]

# 4. Block form
field :x, :string do
  sanitize :trim
  validate :string
end

# 5. Pipe form
field :x, :string,
  derive: GuardedStruct.Sanitize.trim() |> GuardedStruct.Validate.string()

Validate boundary semantics

{:min_len, n} and {:max_len, n} use String.length/1 on binaries, value comparison on integers/floats, range size on Ranges, and length/1 on lists. The classifier is inclusive on both bounds (<= / >=).

Standalone API

GuardedStruct.Validate.run("validate(email_r)", "alice@x.io")
# => {:ok, "alice@x.io"}

GuardedStruct.Validate.field(MyApp.User, :email, "bad")
# => {:error, [%{field: :email, action: :email_r, message: ...}]}