OCAML(1) General Commands Manual OCAML(1)
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 # (sharp) 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).
-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 +labltk adds the sub-
directory labltk 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. The default file is .ocamlinit in the current directory if it
exists, otherwise .ocamlinit in the user's home directory.
-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.
-noassert
Do not compile assertion checks. Note that the special form assert false is always compiled because it is typed specially.
-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.
-principal
Check information path during type-checking, to make sure that all types are derived in a principal way. When using labelled argu-
ments and/or polymorphic methods, this flag is required to ensure future versions of the compiler will be able to infer types cor-
rectly, 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.
-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.
-version
Print version string and exit.
-vnum Print short version number and exit.
-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
Treat as errors the warnings described by the argument warning-list. Note that a warning is not triggered (and not treated as
error) if it is disabled by the -w option. See ocamlc(1) for the syntax of the warning-list argument.
-help or --help
Display a short usage summary and exit.
ENVIRONMENT VARIABLES
LC_CTYPE
If set to iso_8859_1, accented characters (from the ISO Latin-1 character set) in string and character literals are printed as is;
otherwise, they are printed as decimal escape sequences.
TERM When printing error messages, the toplevel system attempts to underline visually the location of the error. It consults the TERM
variable to determines the type of output terminal and look up its capabilities in the terminal database.
SEE ALSO
ocamlc(1), ocamlopt(1), ocamlrun(1).
The OCaml user's manual, chapter "The toplevel system".
OCAML(1)