Title here
Summary here
Structs in OCaml
The struct type in the code has name and age fields.
OCaml uses record types for a similar purpose.
In this example, the person type is a record type, and new_person is a function that creates a new person record with the given name.
Here’s the full source code translated to OCaml:
Structs
Explanation:
OCaml’s record types are typed collections of fields. They are useful for grouping data together to form records.
OCaml Code:
type person = { name : string; mutable age : int }
let new_person name =
let p = { name = name; age = 42 } in
p
let () =
(* This syntax creates a new record *)
Printf.printf "%s\n" (match { name = "Bob"; age = 20 } with person -> Printf.sprintf "%s %d" person.name person.age);
(* You can name the fields when initializing a record *)
Printf.printf "%s\n" (match { name = "Alice"; age = 30 } with person -> Printf.sprintf "%s %d" person.name person.age);
(* Omitted fields will be zero-valued *)
Printf.printf "%s\n" (match { name = "Fred"; age = 0 } with person -> Printf.sprintf "%s %d" person.name person.age);
(* Using a mutable record field to update a field's value *)
let s = { name = "Sean"; age = 50 } in
Printf.printf "%s\n" s.name;
(* Access record fields *)
Printf.printf "%d\n" s.age;
(* Record fields are mutable so their values can be updated *)
let sp = s in
sp.age <- 51;
Printf.printf "%d\n" s.age;
(* Creating an anonymous record type *)
let dog = { name = "Rex"; isGood = true } in
Printf.printf "%s %s\n" (dog.name) (string_of_bool dog.isGood)Explanation:
- The
personrecord type hasnameandagefields. - The
new_personfunction constructs a newpersonrecord with the given name and an age of 42. - A new record is created and its fields are printed using
Printf.printf. - Naming fields when initializing a record.
- Omitting fields will result in zero-valued fields.
- Accessing and updating record fields directly.
- Creating and using an anonymous record type.
To run the program, put the code in a file (e.g., structs.ml) and use the OCaml compiler:
$ ocamlc -o structs structs.ml
$ ./structs
Bob 20
Alice 30
Fred 0
Sean
50
51
Rex true