Ubuntu Manpage: ocaml - The OCaml interactive toplevel

Provided by: ocaml-interp_4.13.1-3ubuntu1_amd64

NAME

       ocaml - The OCaml interactive toplevel

SYNOPSIS

       ocaml [ options ] [ object-files ] [ script-file ]

DESCRIPTION

       The ocaml(1) command is the toplevel system for OCaml, that permits interactive use of the
       OCaml system through a read-eval-print loop. In this mode,  the  system  repeatedly  reads
       OCaml  phrases  from  the input, then typechecks, compiles and evaluates them, then prints
       the inferred type and result value, if any. The system prints a  #  (hash)  prompt  before
       reading each phrase.

       A toplevel phrase can span several lines. It is terminated by ;; (a double-semicolon). The
       syntax of toplevel phrases is as follows.

       The toplevel system is started by the command ocaml(1).   Phrases  are  read  on  standard
       input,  results  are  printed on standard output, errors on standard error. End-of-file on
       standard input terminates ocaml(1).

       If one or more object-files (ending in .cmo or .cma) are given, they are  loaded  silently
       before starting the toplevel.

       If  a  script-file  is  given,  phrases are read silently from the file, errors printed on
       standard error.  ocaml(1) exits after the execution of the last phrase.

OPTIONS

The following command-line options are recognized by ocaml(1).

-absname
Show absolute filenames in error messages.

-I directory
Add the given directory to the list of directories searched for source and compiled
files. By default, the current directory is searched first, then the standard
library directory. Directories added with -I are searched after the current
directory, in the order in which they were given on the command line, but before
the standard library directory.

If the given directory starts with +, it is taken relative to the standard library
directory. For instance, -I +compiler-libs adds the subdirectory compiler-libs of
the standard library to the search path.

Directories can also be added to the search path once the toplevel is running with
the #directory directive.

-init file
Load the given file instead of the default initialization file. See the
"Initialization file" section below.

-labels
Labels are not ignored in types, labels may be used in applications, and labelled
parameters can be given in any order. This is the default.

-no-app-funct
Deactivates the applicative behaviour of functors. With this option, each functor
application generates new types in its result and applying the same functor twice
to the same argument yields two incompatible structures.

-noassert
Do not compile assertion checks. Note that the special form assert false is always
compiled because it is typed specially.

-noinit
Do not load any initialization file. See the "Initialization file" section below.

-nolabels
Ignore non-optional labels in types. Labels cannot be used in applications, and
parameter order becomes strict.

-noprompt
Do not display any prompt when waiting for input.

-nopromptcont
Do not display the secondary prompt when waiting for continuation lines in multi-
line inputs. This should be used e.g. when running ocaml(1) in an emacs(1) window.

-nostdlib
Do not include the standard library directory in the list of directories searched
for source and compiled files.

-open module
Opens the given module before starting the toplevel. If several -open options are
given, they are processed in order, just as if the statements open! module1;; ...
open! moduleN;; were input.

-ppx command
After parsing, pipe the abstract syntax tree through the preprocessor command. The
module Ast_mapper(3) implements the external interface of a preprocessor.

-principal
Check information path during type-checking, to make sure that all types are
derived in a principal way. When using labelled arguments and/or polymorphic
methods, this flag is required to ensure future versions of the compiler will be
able to infer types correctly, even if internal algorithms change. All programs
accepted in -principal mode are also accepted in the default mode with equivalent
types, but different binary signatures, and this may slow down type checking; yet
it is a good idea to use it once before publishing source code.

-rectypes
Allow arbitrary recursive types during type-checking. By default, only recursive
types where the recursion goes through an object type are supported.

-safe-string
Enforce the separation between types string and bytes, thereby making strings read-
only. This is the default.

-short-paths
When a type is visible under several module-paths, use the shortest one when
printing the type's name in inferred interfaces and error and warning messages.

-stdin Read the standard input as a script file rather than starting an interactive
session.

-strict-sequence
Force the left-hand part of each sequence to have type unit.

-unboxed-types
When a type is unboxable (i.e. a record with a single argument or a concrete
datatype with a single constructor of one argument) it will be unboxed unless
annotated with [@@ocaml.boxed].

-no-unboxed-types
When a type is unboxable it will be boxed unless annotated with [@@ocaml.unboxed].
This is the default.

-unsafe
Turn bound checking off on array and string accesses (the v.(i)ands.[i]
constructs). Programs compiled with -unsafe are therefore slightly faster, but
unsafe: anything can happen if the program accesses an array or string outside of
its bounds.

-unsafe-string
Identify the types string and bytes, thereby making strings writable. This is
intended for compatibility with old source code and should not be used with new
software.

-version
Print version string and exit.

-vnum Print short version number and exit.

-no-version
Do not print the version banner at startup.

-w warning-list
Enable or disable warnings according to the argument warning-list. See ocamlc(1)
for the syntax of the warning-list argument.

-warn-error warning-list
Mark as fatal the warnings described by the argument warning-list. Note that a
warning is not triggered (and does not trigger an error) if it is disabled by the
-w option. See ocamlc(1) for the syntax of the warning-list argument.

-color mode
Enable or disable colors in compiler messages (especially warnings and errors).
The following modes are supported:

auto use heuristics to enable colors only if the output supports them (an ANSI-
compatible tty terminal);

always enable colors unconditionally;

never disable color output.

The default setting is auto, and the current heuristic checks that the "TERM"
environment variable exists and is not empty or "dumb", and that isatty(stderr)
holds.

The environment variable "OCAML_COLOR" is considered if -color is not provided. Its
values are auto/always/never as above.

-error-style mode
Control the way error messages and warnings are printed. The following modes are
supported:

short only print the error and its location;

contextual like "short", but also display the source code snippet corresponding to
the location of the error.

The default setting is contextual.

The environment variable "OCAML_ERROR_STYLE" is considered if -error-style is not
provided. Its values are short/contextual as above.

-warn-help
Show the description of all available warning numbers.

- file Use file as a script file name, even when it starts with a hyphen (-).

-help or --help
Display a short usage summary and exit.

INITIALIZATION FILE

       When  ocaml(1)  is invoked, it will read phrases from an initialization file before giving
       control to the user. The default file is .ocamlinit in the current directory if it exists,
       otherwise  XDG_CONFIG_HOME/ocaml/init.ml according to the XDG base directory specification
       lookup if it exists (on Windows this is skipped), otherwise .ocamlinit in the user's  home
       directory  ( HOME variable).  You can specify a different initialization file by using the
       -init file option, and disable initialization files by using the -noinit option.

       Note that you can also use the #use directive to read phrases from a file.

ENVIRONMENT VARIABLES