Lift a comparison order to the lexical order on lists

assoc_equal_opt and assoc_compare_opt are like List.assoc_opt but take equality/comparison functions as arguments, rather than relying on OCaml's built in equality

Apply a function to the last element of a list

Map but pass true to the function for the last element

option_cases None f_s f_n returns f_n, whereas option_cases (Some x) f_s f_n returns f_s x.

option_binop f (Some x) (Some y) returns Some (f x y), and in all other cases, option_binop returns None.

option_get_exn exn None throws the exception exn, whereas option_get_exn exn (Some x) returns x.

option_these xs extracts the elements of the list xs wrapped in Some.

option_all xs extracts the elements of the list xs if all of them are wrapped in Some. If any are None then the result is None is None. option_all [] is Some []

list_index p l returns the first index i such that the predicate p (l!i) holds. If no such i exists, None is returned.

option_first f l searches for the first element x of l such that the f x is not None. If such an element exists, f x is returned, otherwise None.

map_changed f l maps f over l. If for all elements of l the function f returns None, then map_changed f l returns None. Otherwise, it uses x for all elements, where f x returns None, and returns the resulting list.

map_changed_default d f l maps f over l. If for all elements of l the function f returns None, then map_changed f l returns None. Otherwise, it uses d x for all elements x, where f x returns None, and returns the resulting list.

list_iter sf f [a1; ...; an] applies function f in turn to a1; ...; an and calls sf () in between. It is equivalent to begin f a1; sf(); f a2; sf(); ...; f an; () end.

map_all f l maps f over l. If at least one entry is None, None is returned. Otherwise, the Some function is removed from the list.

list_to_front i l resorts the list l by bringing the element at index i to the front.

Throws Failure if i is not smaller than the length of l

undo_list_to_front i l resorts the list l by moving the head element to index index i It's the inverse of list_to_front i l.

split_after n l splits the first n elemenst from list l, i.e. it returns two lists l1 and l2, with length l1 = n and l1 @ l2 = l. Fails if n is too small or large.

split3 l splits a list of triples into a triple of lists

find an item in a list and return that item as well as its index

Alternative to String.starts_with for OCaml < 4.13

remove_suffix s suffix checks if s ends with suffix and returns the rest of the string if so

Compute the levenshtein distance between two strings using the Wagner–Fischer algorithm. If ~osa is true computes the optimal string alignment distance, which is similar but allows swaps as a single action.

copy_file src dst copies file src to file dst. Only files are supported, no directories.

move_file src dst moves file src to file dst. In contrast to Sys.rename no error is produced, if dst already exists. Moreover, in case Sys.rename fails for some reason (e.g. because it does not work over filesystem boundaries), copy_file and Sys.remove are used as fallback.

input_byte_opt chan tries to read a byte b from input channel chan, and returns Some b in case of success, or None if the end of the file was reached.

same_content_files file1 file2 checks, whether the files file1 and file2 have the same content. If at least one of the files does not exist, false is returned. same_content_files throws an exception, if one of the files exists, but cannot be read.

read_whole_file filename reads the contents of the file and returns it as a string.

string_to_list l translates the string l to the list of its characters.

Sets of integers and strings

Encode string for use as a filename. We can't use zencode directly because some operating systems make the mistake of being case-insensitive.

always_replace_files determines whether Sail only updates modified files. If it is set to true, all output files are written, regardless of whether the files existed before. If it is set to false and an output file already exists, the output file is only updated, if its content really changes.

open_output_with_check file_name will open a file for output, but will only actually create or update said file if the contents are different to the existing contents of said file when the output is closed. This means it works well for compiler artifacts that are referenced by tools like Make. The 'check' that the file actually needs updating happens in the close_output_with_check function, so it is especially important that any call to this is matched with that function otherwise no actual output will happen.

Takes an optional directory argument, which will cause the file to be created in a subdirectory of the current directory. The subdirectory will be created (by the close_output_with_check function) if it doesn't exist.