OCAML(1)OCAML(1)NAMEocaml - The OCaml interactive toplevel
SYNOPSISocaml [ 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).
-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.
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 applica‐
tions, 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.
-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 continua‐
tion 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 pre‐
processor 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 pro‐
grams accepted in -principal mode are also accepted in the
default mode with equivalent types, but different binary signa‐
tures, 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 will become the default in a
future version of OCaml.
-short-paths
When a type is visible under several module-paths, use the
shortest one when printing the type's name in inferred inter‐
faces 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.
-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. For reasons of backward compatibility, this is the
default setting for the moment, but this will change in a future
version of OCaml.
-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 argu‐
ment.
-warn-error warning-list
Mark as fatal the warnings described by the argument warn‐
ing-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.
-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.
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 ALSOocamlc(1), ocamlopt(1), ocamlrun(1).
The OCaml user's manual, chapter "The toplevel system".
OCAML(1)
