Search inside the OCaml documentation

1. Transitioning to Multicore with ThreadSanitizer

   Final Remarks and a Word of Warning

   fix as follows: The programming pattern of 'always-having-to-do-something-at-the-end' that we encountered with the missing Mutex.unlock is a recurring one for which OCaml offers a dedicated function:

   Guides

2. How to Work with the Garbage Collector

   The Gc Module

   .ml --> <!-- TODO: Probably write a GC example without dependencies --> Here is a program that runs and then prints out GC statistics just before quitting: The Gc module contains some useful functions for querying and calling the garbage collector from OCaml programs.

   Guides

3. How to Work with the Garbage Collector

   Exercises

   xtend the program so it acquires a read lock on getting the record, but upgrades this to a write lock just before the user updates any field. Support a variable number of records , and add a function to create a new record (in the file). [Tip: OCaml has support for weak hashtables.] Add support for variable-length records . Make the underlying file representation a DBM-style hash . Provide

   Guides

4. OCaml Programming Guidelines

   Usage in Module Interface

   The function's usage must appear in the module's interface that exports it, not in the program that implements it. Choose comments as in the OCaml system's interface modules, which will subsequently automatic

   Resources

5. OCaml Programming Guidelines

   Use Assertions

   is verified upon each execution, while a comment can quickly become obsolete, making it detrimental to understanding the program. <!-- $MDX skip --> For example, the conditions to validate a function's arguments are usefully verified by assertions. Use assertions as much as possible, as they let you avoid verbose comments while allowing a useful verification upon execution.

   Resources

6. OCaml Programming Guidelines

   Don't use abbreviations for global names

   Global identifiers (including the names of functions) can be long because it's important to understand what purpose they serve far from their definition.

   Resources

7. OCaml Programming Guidelines

   Subdividing into modules

   For each interface, you must document the things defined by the module: functions, types, exceptions, etc. For each module, you must explicitly write an interface. You must subdivide your programs into coherent modules.

   Resources

8. OCaml Programming Guidelines

   Single branches

   If cond , e1 , and e2 are small, simply write them on one line: If the expressions making up a conditional are purely functional (without side effects), we advocate binding them within the conditional by using let e = ... in when they're too big to fit on a single line. Justification : This way you get back the sim

   Resources

9. Comparison of Standard Containers

   Lists: Immutable Singly-Linked Lists

   Not very efficient for: random access, indexed elements Well-suited for: I/O, pattern-matching Adding an element: O(1) , cons operator :: Length: O(n) , function List.length Accessing cell i : O(i) Finding an element: O(n) Adding an element always creates a new list l from an element x List tl . tl remains unchanged, but it is not copied either.

   Resources

10. Comparison of Standard Containers

    Arrays: Mutable Vectors

    of elements of known size, accessing elements by numeric index, and modifying in-place elements. Basic arrays have a fixed length. Adding an element (by creating a new array): O(n) Length: O(1) , function Array.length Accessing cell i : O(1) Finding an element: O(n) Arrays are mutable data structures with a fixed length and random access.

    Resources

11. A Tour of OCaml

    Type Conversion and Type-Inference

    ison to other languages. Arguably, this saves more time than we lose by being more explicit. In OCaml you need to explicitly convert the integer to a floating point number using the float_of_int function: In the first example, + is intended to be used with integers, so it can't be used with the 2.5 float. In the second example, +. is intended to be used with floats, so it can't be used with th

    First Steps

12. A Tour of OCaml

    Pattern Matching, Cont'd

    mes, just as let does. In the third pattern, x designates the data inside the double-wrapped option. Pattern matching isn't limited to lists. Any kind of data can be inspected using it, except functions. Patterns are expressions that are compared to an inspected value. It could be performed using if … then … else … , but pattern matching is more convenient. Here is an example using the opti

    First Steps

13. A Tour of OCaml

    Records

    Here, the pattern { age = x; _ } is typed with the most recently declared record type that has an age field of type int . The type int is inferred from the expression 13 <= x && x <= 19 . The function is_teenager will only work with the found record type, here person . When defining gerard , no type needs to be declared. The type checker will search for a record which has exactly three fiel

    First Steps

14. Your First OCaml Program

    Installing and Using Modules From a Package

    Refer to the Sexplib documentation for more information. Next, define a string containing a valid S-expression in bin/main.ml . Parse it into an S-expression with the Sexplib.Sexp.of_string function, and then convert it back into a string with Sexplib.Sexp.to_string and print it. To illustrate this, let's update our hello project to parse a string containing an S-expression and print

    First Steps

15. Your First OCaml Program

    Using the Preprocessor to Generate Code

    le, and edit it to look like this: Let's assume we'd like hello to display its output as if it was a list of strings in UTop: ["hello"; "using"; "an"; "opam"; "library"] . To do that, we need a function turning a string list into a string , adding brackets, spaces, and commas. Instead of defining it ourselves, let's generate it automatically with a package. We'll use ppx_deriving . Here is how t

    First Steps

16. Configuring Your Editor

    1) Hovering for Type Information

    This is a great feature that lets you see type information of any OCaml variable or function. All you have to do is place your cursor over the code and it will be displayed in the tooltip. VSCode Hovering

    Tooling

17. Configuring Your Editor

    Choosing a major mode

    nd actively maintained mode with comprehensive OCaml support. Recommended if you're using an older version of Emacs (before the introduction of tree-sitter support) or you need some of the advanced functionality that Tuareg provides. Caml : an older, lighter mode that is softly deprecated at this point. Neocaml : a newer mode based on tree-sitter , requiring Emacs 30+. There are several major modes de

    Tooling

18. Configuring Your Editor

    Finer configuration

    OCaml-eglot can be finely configured, the project README gives several configuration paths to adapt perfectly to your workflow. You will also find there an exhaustive presentation of the different functions offered by the mode.

    Tooling

19. Configuring Your Editor

    Getting Type Information

    OCaml-eglot README provides a comprehensive overview of all the functions available in this mode! Emacs Type information Opening an OCaml file should launch an ocaml-lsp server, and you can convince yourself that it's working by using, for example, the ocaml-eglot-ty

    Tooling