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1. Profiling

   Further Reading

   p of pointer indirection. Objects in OCaml are also dynamically dispatched. Since this is the point with polymorphism in an OO setting. * Dynamic method dispatch often hinders a compiler to inline function and this hits the performance. * In Java is a dynamic type check (aka cast) much more expensive than a dynamic method dispatch. --> You can find out more about how OCaml represents different typ

   Guides

2. Command-line Arguments

   Sys.argv

   ndard library, therefore its full name is Sys.argv . The number of arguments including the name of the program itself is simply the length of the array. It is obtained using the Array.length function.

   Tutorials

3. File Manipulation

   Writing

   Standard out_channel s: stdout , stderr Commonly used functions: open_out , open_out_bin , flush , close_out , close_out_noerr Open the file to obtain an out_channel Write to the channel If you want to force writing to the physical device, you must flush

   Tutorials

4. File Manipulation

   Reading

   Standard in_channel : stdin Commonly used functions: open_in , open_in_bin , close_in , close_in_noerr Open the file to obtain an in_channel Read characters from the channel. Reading consumes the channel, so if you read a character, the chan

   Tutorials

5. 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

6. 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

7. 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

8. 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

9. Transitioning to Multicore with ThreadSanitizer

   Address the Reported Races and Rerun the Tests, Take 2 (Steps 3 and 2)

   ml 5.x parallelism, hurrah! We can now rerun our tests under TSan to confirm the fix: Oh, wait! When raising an exception in transfer , we forgot to unlock the Mutex again. Let's adapt the function to do so:

   Guides

10. Transitioning to Multicore with ThreadSanitizer

    Final Remarks and a Word of Warning

    l 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 dedicate function:

    Guides

11. Error Handling

    Documentation

    <!-- $MDX skip --> Functions that can raise exceptions should be documented like this:

    Guides

12. Error Handling

    Language Bugs

    sh File an issue in the OCaml Bug Tracker in GitHub it may be a language bug. It happens. Here is what to do when this is suspected: A limitation of the native code compiler An inherently unsafe function such as are found in modules Marshal and Obj When a crash isn't coming from:

    Guides

13. Error Handling

    External Resources

    odule result in Ocaml Library “Error Handling” in “Real World OCaml”, part 7, Yaron Minsky and Anil Madhavapeddy, 2ⁿᵈ edition, Cambridge University Press, October 2022 “Add "finally" function to Pervasives”, Marcello Seri, GitHub PR, ocaml/ocaml/pull/1855 “A guide to recover from interrupts”, Guillaume Munch-Maccagnoni, parf the memprof-limits documentation

    Guides

14. Using the OCaml Compiler Toolchain

    The ocamlc and ocamlopt Compilers

    tance, if you create a file graphics.ml and use the graphics library, the Graphics module exposed from the graphics library will be hidden by your newly defined module, hence all of the functions defined in it will be made inaccessible. Moving on, we'll see how to use ocamlopt . Let's assume that our program program has two source files, module1.ml and module2.ml . We will compile

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