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).
- -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 +labltk adds
the subdirectory 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.
- -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 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.
- -ppx command
- After parsing, pipe the abstract syntax tree through the preprocessor
command. The format of the input and output of the preprocessor are
not yet documented.
- -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.
- -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.
- -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
- 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.
- -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 ALSO¶
ocamlc(1),
ocamlopt(1),
ocamlrun(1).
The OCaml user's manual, chapter "The toplevel
system".