The batch compiler

Moscow ML includes a batch compiler mosmlc in addition to the interactive system mosml. It compiles and links programs non-interactively, and can turn them into standalone executable files. The batch compiler can be invoked from a Makefile, which simplifies the (re)compilation of large programs considerably; see Section 6.

Overview

The mosmlc command has a command-line interface similar to that of most C compilers. It accepts several types of arguments: source files for unit bodies, source files for unit signatures, and compiled unit bodies.

• An argument ending in .sig is taken to be the name of a source file containing a unit signature. Given a file U.sig, the compiler produces a compiled signature in the file U.ui.
• An argument ending in .sml is taken to be the name of a source file containing a unit body. Given a file U.sml, the compiler produces compiled object code in the file U.uo. It also produces an inferred signature file U.ui if there is no explicit signature U.sig.
• An argument ending in .uo is taken to be the name of a compiled unit body. Such files are linked together, along with the compiled unit bodies obtained by compiling .sml arguments (if any), and the necessary Moscow ML library files, to produce a standalone executable program. The order in which .uo and .sml arguments are presented (from left to right) on the command line is significant: top-level declarations are evaluated and global identifiers are initialized in that order at run-time. In particular, file U.uo must come before any file which mentions identifiers U.id defined in U or which contains a declaration open U.

The output of the linking phase is a file containing compiled code that can be executed by the runtime system camlrunm. If mosmlout is the name of the file produced by the linking phase, the command

executes the compiled code contained in mosml.out. The arguments can be accessed from the Moscow ML program via function Mosml.argv; see file mosml/lib/Mosml.sig.

MS DOS:

If the output file produced by the linking phase has extension .exe, and option -noheader is not used, then the file is directly executable. Hence, an output file named mosmlout.exe can be executed with the command

The output file mosmlout.exe consists of a tiny executable file prepended to a linked bytecode file. The executable invokes the camlrunm runtime system to interpret the bytecode. As a consequence, this is not a standalone executable: it still requires camlrunm.exe to reside in one of the directories in the path.

Unix:

The output file produced by the linking phase is directly executable (unless the -noheader option is used). It automatically invokes the camlrunm runtime system, either using a tiny executable prepended to the linked bytecode file, or using the Unix incantation #!/usr/local/bin/camlrunm. In the former case, camlrunm must be in one of the directories in the path; in the latter case it must be in /usr/local/bin. To create a true stand-alone executable you may simply concatenate the runtime system with the bytecode file produced by mosmlc -noheader, but this adds 60-150 KB to the size of the executable, depending on your version of Unix:

Command-line options

The following command-line options are recognized by mosmlc.

-c

Compile only. Suppresses the linking phase of the compilation. Source code files are turned into compiled files (.ui and .uo), but no executable file is produced. This option is useful for compiling separate units.

-files response-file

Pass the names of files listed in file response-file to the linking phase just as if these names appeared on the command line. File names in response-file are separated by blanks (spaces, tabs, newlines) and must end either in .sml or .uo. A name U.sml appearing in the response file is equivalent to U.uo. Use this option to overcome silly limitations on the length of the command line (as in DOS).

-g

This option causes some information about exception names to be written at the end of the executable bytecode file.

-i

Causes the compiler to print the inferred signature of the unit body or bodies being compiled. Also causes the linker to list all object files linked. A U.sig file corresponding to a given U.sml file can be produced semi-automatically by piping the output of the compiler to a file U.out, and subsequently editing this file to obtain a file U.sig.

-noautolink

In version 1.42 and later, the linker automatically links in any additional object files required by the files explicitly specified on the command line. Option -noautolink reinstates the behaviour of previous versions: all object files must be explicitly specified in the appropriate order.

-stdlib stdlib-directory

Specifies the standard library directory, which will be searched by the compiler and linker for the .ui and .uo files corresponding to units mentioned in the files being linked. The default standard library is set when the system is created, and is usually ${HOME}/mosml/lib under Unix and c:\mosml\lib under DOS.

-I directory

Add the given directory to the list of directories searched for compiled signature files (.ui) and compiled object code files (.uo). By default, the current directory is searched first, then the standard library directory. Directories added with -I are searched after the current directory, but before the standard library directory. When several directories are added with several -I options on the command line, these directories are searched from left to right.

-valuepoly

Specify that the type checker should use `value polymorphism'; see Section 7. The default.

-imptypes

Specify that the type checker should distinguish imperative and applicative type variables, generalize all applicative type variables, and generalize imperative type variables only in non-expansive expressions. See Section 7.

-o exec-file

Specify the name of the output file produced by the linker. In the absence of this option, a default name is used. In MS DOS, the default name is mosmlout.exe; in Unix it is a.out.

-P unit-set

Determines which library units will be open at compile-time.

-P default

This provides an initial environment for the new Basis Library, compatible with future versions of SML/NJ. The units Array, Char, List, String, and Vector will be available for linking, and units Char, List, and String will be partially opened. This is the default.

-P sml90

This provides an initial environment which is upwards compatible with that of the Definition of Standard ML and with pre-1.30 releases of Moscow ML. In particular, the functions chr, explode, implode, and ord work on strings, not characters. The new versions of these functions are available as Char.chr, Char.ord, String.explode, and String.implode. The math functions and input-output facilities required by the Definition [6, Appendix C and D,] are available at top-level. In addition the same (new) libraries are available for linking as with -P default.

-P nj93

This provides a top-level environment which is mostly compatible with that of SML/NJ 0.93. The functions app, ceiling, chr, dec, explode, fold, hd, implode, inc, max, min, nth, nthtail, ord, ordof, revapp, revfold, substring, tl, and truncate have the same type and meaning as in SML/NJ 0.93. The math functions and input-output facilities required by the Definition [6, Appendix C and D,] are available at top-level. In addition the same (new) libraries are available for linking as with -P default. This option does not imply -valuepoly or -imptypes.

-P full

This makes all the libraries marked F in the library list (see [8]) available for linking, and partially opens the Char, List, and String units.

-P none

No library units are available for linking or initially opened.

Additional library units to be linked in can be specified by listing them on the command line, or by using the -I directory option.

-noheader

Causes the output file produced by the linker to contain only the bytecode, not preceded by any executable code. A file mosmlout thus obtained can be executed only by explicitly invoking the runtime system as follows: camlrunm mosmlout. This option is primarily used for recompiling the system.

-q

Enable the quotation/antiquotation mechanism; see Section 8.

-v

Print the version number of the various passes of the compiler.