Deserialise YAML Data using yaml

Task

Data Formats / YAML / Deserialise YAML Data

Opam Packages Used

• yaml Tested with version: 3.2.0 — Used libraries: yaml
• ppx_deriving_yaml Tested with version: 0.2.2 — Used libraries: ppx_deriving_yaml

Code

(* This is the string we are deserializing into the types we define below. *) let yaml = {| french name: pâte sucrée ingredients: - name: flour weight: 250 - name: butter weight: 100 - name: sugar weight: 100 - name: egg weight: 50 - name: salt weight: 5 steps: - soften butter - add sugar - add egg and salt - add flour |} (* The `[@@deriving of_yaml]` attribute makes makes the ppx from the library `ppx_deriving_yaml` generate the function ``ingredient_of_yaml : Yaml.value -> (ingredient, [> `Msg of string]) result`` If both serialising and deserialising are needed, replace `of_yaml` by `yaml`. *) type ingredient = { name: string; weight: int; } [@@deriving of_yaml] (* The function ``recipe_of_yaml : Yaml.value -> (ingredient, [> `Msg of string]) result`` generated here internally uses `ingredient_of_yaml`. *) type recipe = { name: string; [@key "french name"] ingredients: ingredient list; steps: string list; } [@@deriving of_yaml] (* Parsing and conversion into record are chained. *) let pate_sucree = yaml |> Yaml.of_string |> fun yaml -> Result.bind yaml recipe_of_yaml

let yaml = {|
french name: pâte sucrée
ingredients:
- name: flour
  weight: 250
- name: butter
  weight: 100
- name: sugar
  weight: 100
- name: egg
  weight: 50
- name: salt
  weight: 5
steps:
- soften butter
- add sugar
- add egg and salt
- add flour
|}

type ingredient = {
  name: string;
  weight: int;
} [@@deriving of_yaml]

type recipe = {
  name: string; [@key "french name"]
  ingredients: ingredient list;
  steps: string list;
} [@@deriving of_yaml]

let pate_sucree =
  yaml
  |> Yaml.of_string
  |> fun yaml -> Result.bind yaml recipe_of_yaml

Recipe not working? Comments not clear or out of date?

Other Recipes for this Task

• Deserialise YAML Data

  hl_yaml ppx_deriving_yojson