Programming

assert

Ensure that a condition is satisfied (raise error.assertion exception otherwise).

Type:

(bool) -> unit

Arguments:

• (unlabeled) (of type bool): Condition which should be satisfied.

cron.add

Add an entry to the cron tab.

Type:

(?id : string?, string, (() -> unit)) -> unit

Arguments:

• id (of type string?, which defaults to null): Optional task ID.
• (unlabeled) (of type string): Cron entry
• (unlabeled) (of type () -> unit): Function to execute

Methods:

• id (of type string): ID to be used to remove the task.

cron.remove

Remove a cron tab entry. ID is returned during the task's registration

Type:

(string) -> unit

Arguments:

• (unlabeled) (of type string)

error.kind

Return error kind

Type:

(error) -> string

Arguments:

• (unlabeled) (of type error)

error.message

Return error message

Type:

(error) -> string

Arguments:

• (unlabeled) (of type error)

error.on_error

Register a callback to monitor errors raised during the execution of the program. The callback is allow to re-raise a different error if needed. The callback passed to this function is called on every errors, not just uncaught errors.

Type:

(((error
   .{
     kind : string,
     message : string,
     trace : [
              {
                cstart : int,
                cstop : int,
                filename : string,
                lstart : int,
                lstop : int,
                to_string : (?prefix : string) -> string
              }]
   }) -> unit)) -> unit

Arguments:

• (unlabeled) (of type (error .{ kind : string, message : string, trace : [ { cstart : int, cstop : int, filename : string, lstart : int, lstop : int, to_string : (?prefix : string) -> string }] }) -> unit)

error.raise

Raise an error.

Type:

(error, ?string) -> 'a

Arguments:

• (unlabeled) (of type error): Error kind.
• (unlabeled) (of type string, which defaults to ""): Description of the error.

error.register

Register an error of the given kind

Type:

(string) -> error

Arguments:

• (unlabeled) (of type string): Kind of the error

Methods:

• kind (of type string): Error kind.
• message (of type string): Error message.
• trace (of type [ { cstart : int, cstop : int, filename : string, lstart : int, lstop : int, to_string : (?prefix : string) -> string }]): Error stacktrace.

failwith

Major failure.

Type:

(string) -> 'a

Arguments:

• (unlabeled) (of type string): Explanation about the failure.

fst

Get the first component of a pair.

Type:

(('a * 'b)) -> 'a

Arguments:

• (unlabeled) (of type 'a * 'b)

ignore

Convert anything to unit, preventing warnings.

Type:

('a) -> unit

Arguments:

• (unlabeled) (of type 'a)

memoize

Memoize the result of a function, making sure it is only executed once.

Type:

((() -> 'a)) -> () -> 'a where 'a is an orderable type

Arguments:

• (unlabeled) (of type () -> 'a where 'a is an orderable type)

null

Create a nullable value.

Type:

(?'a?) -> 'a?

Arguments:

• (unlabeled) (of type 'a?, which defaults to null): Value to make nullable.

null.case

Return a result dending on whether a value is nothing or not.

Type:

('a?, (() -> 'b), (('a) -> 'b)) -> 'b

Arguments:

• (unlabeled) (of type 'a?): Value to reason by case analysis on.
• (unlabeled) (of type () -> 'b): Value to return in case we have nothing.
• (unlabeled) (of type ('a) -> 'b): Value to return in case we have something.

null.default

Return a result dending on whether a value is nothing or not.

Type:

('a?, (() -> 'a)) -> 'a

Arguments:

• (unlabeled) (of type 'a?): Value to reason by case analysis on.
• (unlabeled) (of type () -> 'a): Value to return in case we have nothing.

null.defined

Determine whether a nullable value is not null.

Type:

('a?) -> bool

Arguments:

• (unlabeled) (of type 'a?)

null.find

Find the first element of a list for which the image of the function is not null. Raises error.not_found if not element is found and no default value was specified.

Type:

(?default : 'a??, (('b) -> 'a?), ['b]) -> 'a?

Arguments:

• default (of type 'a??, which defaults to null): Returned value when no element is found.
• (unlabeled) (of type ('b) -> 'a?): Function.
• (unlabeled) (of type ['b]): List.

null.get

Get the value of a nullable. Raises error.not_found if the value is null and no default value was specified.

Type:

(?default : 'a?, 'a?) -> 'a

Arguments:

• default (of type 'a?, which defaults to null): Returned value when the value is null.
• (unlabeled) (of type 'a?)

null.map

Apply a function on a nullable value if it is not null, and return null otherwise.

Type:

((('a) -> 'b?), 'a?) -> 'b?

Arguments:

• (unlabeled) (of type ('a) -> 'b?)
• (unlabeled) (of type 'a?)

null.to_list

Convert a nullable value to a list containing zero or one element depending on whether the value is null or not.

Type:

('a?) -> ['a]

Arguments:

• (unlabeled) (of type 'a?)

position

Return the current position in the script

Type:

() -> unit

Methods:

• cstart (of type int): Starting character
• cstop (of type int): Stopping character
• filename (of type string): Filename
• lstart (of type int): Starting line
• lstop (of type int): Stopping line
• to_string (of type (?prefix : string) -> string): Render as string

predicate.activates

Detect when a predicate becomes true.

Type:

(?init : bool, (() -> bool)) -> () -> bool

Arguments:

• init (of type bool, which defaults to false): Detect at beginning.
• (unlabeled) (of type () -> bool): Predicate.

predicate.at_most

Limit the number of times a predicate is true is a row.

Type:

(int, (() -> bool)) -> () -> bool

Arguments:

• (unlabeled) (of type int): Number of times the predicate is allowed to be true.
• (unlabeled) (of type () -> bool): Predicate.

predicate.changes

Detect when a predicate changes.

Type:

((() -> 'a)) -> () -> bool where 'a is an orderable type

Arguments:

• (unlabeled) (of type () -> 'a where 'a is an orderable type): Predicate.

predicate.first

First occurrence of a predicate.

Type:

((() -> bool)) -> () -> bool

Arguments:

• (unlabeled) (of type () -> bool): Predicate.

predicate.once

Become true once every time a predicate is true.

Type:

((() -> bool)) -> () -> bool

Arguments:

• (unlabeled) (of type () -> bool): Predicate.

predicate.signal

Predicate which is true when a signal is sent. The returned predicate has a method signal to send the signal.

Type:

() -> () -> bool

Methods:

• signal (of type () -> unit): Send a signal.

print

Print on standard output.

Type:

(?newline : bool, 'a) -> unit

Arguments:

• newline (of type bool, which defaults to true): If true, a newline is added after displaying the value.
• (unlabeled) (of type 'a)

ref

Create a reference, i.e. a value which can be modified.

Type:

('a) -> () -> 'a

Arguments:

• (unlabeled) (of type 'a)

Methods:

• set (of type ('A) -> unit): Set the value of the reference.

ref.getter

Create a getter from a reference (sometimes useful to remove the set method).

Type:

((() -> 'a).{set : ('a) -> unit}) -> () -> 'a

Arguments:

• (unlabeled) (of type (() -> 'a).{set : ('a) -> unit})

ref.incr

Increment a reference to an integer.

Type:

((() -> int).{set : (int) -> unit}) -> unit

Arguments:

• (unlabeled) (of type (() -> int).{set : (int) -> unit})

ref.make

Create a reference from a pair of get / set functions.

Type:

((() -> 'a), (('a) -> unit)) -> () -> 'a

Arguments:

• (unlabeled) (of type () -> 'a): Function to retrieve the value of the reference.
• (unlabeled) (of type ('a) -> unit): Function to change the value of the reference.

Methods:

• set (of type ('A) -> unit): Set the value of the reference.

ref.map

Map functions to a reference.

Type:

((('a) -> 'b), (('b) -> 'a), (() -> 'a).{set : ('a) -> unit}) -> () -> 'b

Arguments:

• (unlabeled) (of type ('a) -> 'b): Function to apply to the getter.
• (unlabeled) (of type ('b) -> 'a): Function to apply to the setter.
• (unlabeled) (of type (() -> 'a).{set : ('a) -> unit})

Methods:

• set (of type ('A) -> unit): Set the value of the reference.

snd

Get the second component of a pair.

Type:

(('a * 'b)) -> 'b

Arguments:

• (unlabeled) (of type 'a * 'b)

sqlite

Manipulate an SQLITE database.

Type:

(string) -> unit

Arguments:

• (unlabeled) (of type string): File where the data base is stored

Methods:

• close (of type () -> unit): Close the database. It should not be accessed afterward.
• count (of type (table : 'a, ?where : string) -> int):
• delete (of type (table : 'a, ?where : string) -> unit):
• exec (of type (string) -> unit): Execute an SQL operation.
• insert (of type ((table : string, ?replace : bool, 'A) -> unit) .{list : (table : string, [string * string]) -> unit} where 'A is a record with int, float, string or null methods.):
• iter (of type (((sqlite.row.{to_list : () -> [string * string?]}) -> unit), string) -> unit): Iterate a function over all the results of a query. Result can be parsed using let sqlite.row = ....
• query (of type (string) -> [sqlite.row.{to_list : () -> [string * string?]}]): Execute an SQL operation returning the result. Result can be parsed using let sqlite.query = ....
• select (of type ((table : 'a, ?string, ?where : string, ?limit : 'b?) -> [sqlite.row.{to_list : () -> [string * string?]}]) .{ iter : 'c.(((sqlite.row.{to_list : () -> [string * string?]}) -> unit), table : 'c, ?string, ?where : string) -> unit }):
• table (of type { create : 'a.'b.'c.('a, ?preserve : bool, ['b * 'c]) -> unit, drop : 'a.('a, ?existing : bool) -> unit, exists : (string) -> string }):

sqlite.escape

Escape a string for use in a query.

Type:

(string) -> string

Arguments:

• (unlabeled) (of type string): String to escape.

thread.delay

Delay the current thread by the given duration in seconds.

Type:

(float) -> unit

Arguments:

• (unlabeled) (of type float)

thread.on_error

Register the function to be called when an error of the given kind is raised in a thread. Catches all errors if first argument is null.

Type:

(error?, ((backtrace : string, error) -> unit)) -> unit

Arguments:

• (unlabeled) (of type error?)
• (unlabeled) (of type (backtrace : string, error) -> unit)

thread.pause

Pause execution for a given amount of seconds. This puts the calling thread to sleep and should not be used in the main streaming loop.

Type:

(float) -> unit

Arguments:

• (unlabeled) (of type float): Number of seconds of pause.

thread.run

Run a function in a separate thread.

Type:

(?fast : bool, ?delay : float, ?on_error : ((error) -> unit)?,
 ?every : {float}?, (() -> unit)) -> unit

Arguments:

• fast (of type bool, which defaults to true): Whether the thread is supposed to return quickly or not. Typically, blocking tasks (e.g. fetching data over the internet) should not be considered to be fast. When set to false its priority will be lowered below that of request resolutions and fast timeouts. This is only effective if you set a dedicated queue for fast tasks, see the "scheduler" settings for more details.
• delay (of type float, which defaults to 0.0): Delay (in seconds) after which the thread should be launched.
• on_error (of type ((error) -> unit)?, which defaults to null): Error callback executed when an error occurred while running the given function. When passed, all raised errors are silenced unless re-raised by the callback.
• every (of type {float}?, which defaults to null): How often (in seconds) the thread should be run. If negative or null, run once.
• (unlabeled) (of type () -> unit): Function to execute.

thread.run.recurrent

Run a recurrent function in a separate thread.

Type:

(?fast : bool, ?delay : float, ?on_error : ((error) -> float)?,
 (() -> float)) -> unit

Arguments:

• fast (of type bool, which defaults to true): Whether the thread is supposed to return quickly or not. Typically, blocking tasks (e.g. fetching data over the internet) should not be considered to be fast. When set to false its priority will be lowered below that of request resolutions and fast timeouts. This is only effective if you set a dedicated queue for fast tasks, see the "scheduler" settings for more details.
• delay (of type float, which defaults to 0.0): Delay (in sec.) after which the thread should be launched.
• on_error (of type ((error) -> float)?, which defaults to null): Error callback executed when an error occurred while running the given function. When passed, all raised errors are silenced unless re-raised by the callback.
• (unlabeled) (of type () -> float): Function to execute recurrently. The returned value is the delay (in sec.) in which the function should be run again (it won't be run if the value is strictly negative).

thread.when

Execute a callback when a predicate is true. The predicate is checked every seconds and the callback is called when the predicate returns true after having been false, following the same semantics as predicate.activates.

Type:

(?fast : bool, ?init : bool, ?every : {float}, ?once : bool, ?changed : bool,
 ?on_error : ((error) -> float)?, ?batched : bool, (() -> bool), (() -> 'a)) ->
unit

Arguments:

• fast (of type bool, which defaults to true): Whether the callback is supposed to return quickly or not.
• init (of type bool, which defaults to true): Detect at beginning.
• every (of type {float}, which defaults to 0.5): How often (in sec.) to check for the predicate.
• once (of type bool, which defaults to false): Execute the function only once.
• changed (of type bool, which defaults to true): Execute the function only if the predicate was false when last checked.
• on_error (of type ((error) -> float)?, which defaults to null): Error callback executed when an error occurred while running the given function. When passed, all raised errors are silenced unless re-raised by the callback.
• batched (of type bool, which defaults to true): When fast is true, every is a fixed value, on_error is null and once is false, we batch callbacks to make it more efficient. Set this argument to false to disable that.
• (unlabeled) (of type () -> bool): Predicate indicating when to execute the function, typically a time interval such as {10h-10h30}.
• (unlabeled) (of type () -> 'a): Function to execute when the predicate is true.

while

A while loop.

Type:

({bool}, (() -> unit)) -> unit

Arguments:

• (unlabeled) (of type {bool}): Condition guarding the loop.
• (unlabeled) (of type () -> unit): Function to execute.