WarningThis version is intended for compiler hackers. We are in the midst of substantial structural changes, and this is a snapshot.
This version transplants the old implementation of the compilation manager (CM) with a brand-new one. It also constitutes a major change in how the files of the interactive compiler are organized.
The basic ideas behind the new CM are identical to those of the old one. However, many, many details have changed, and virtually no code is shared between the two implementations.
Syntax and semantics of CM description files has changed slightly. One important user-visible change is the treatment of the basis library: it has no special status anymore and must be specified as "basis.cm" by anyone who wants to use it.
The new CM offers more robust pathname handling, improved error detection and error reporting, as well as very efficient handling of stable libraries. It is integrated with the interactive toplevel by means of its autoloading mechanism and makes sure that modules that are common to system code (compiler, CM, interactive system) and user code are shared.
Compiler hackers should definitely read the file system/README.
Some details on how to use the new compilation managerCM's API is not yet as complete as the old one. Moreover, there are some semantic changes:
The primary means for structuring a program is now the "library". Please, use "library" where you used "group" before. This means that you will have to specify the export list of your library.
- There is no default description file "sources.cm" anymore. CM.make, CM.autoload, CM.recomp, and CM.stabilize always take string arguments that specify the root description file.
- The syntax of that string argument is CM's "standard" path name notation. In essence, this means Unix-style pathnames (even on a non-Unix system!), but the more important aspect is that "pathname anchors" (see below) are recognized.
- CM no longer searches a list of directories. Instead, there is a new "pathname anchor" mechanism that can be used to establish a fixed mapping from the initial arc of a relative pathname to some other directory. For example, if "a" is mapped to "/usr/share/smlnj/lib", then "a/b/c.sml" will refer to "/usr/share/smlnj/lib/a/b/c.sml". There are pre-defined mappings for libraries such as "basis.cm", "smlnj-lib.cm", "ml-yacc-lib.cm", etc. Thus, if you sayCM.autoload "smlnj-lib.cm";Then CM will register the library<smlnj-installation-dir>/lib/smlnj-lib.cm/smlnj-lib.cmfor autoloading. However, the important point is that you nearly never should have to worry about this mapping.
- The pathname mapping can be modified using CM.setAnchor, CM.cancelAnchor, and CM.resetPathConfig as well as by editing configuration files that are read at startup time. These files are<smlnj-installation-dir>/lib/pathconfig $HOME/.smlnj-pathconfig
- CM tries to be quite careful about pathname elaboration. Barring bugs, it will now be possible to change the working directory, to change the pathname mapping (see above), or to save a session via SMLofNJ.exportML and later resume it in a totally different environment (provided the pathname configuration has been set accordingly).
- If you have an ongoing CM session and you move/rename files that CM knows about in such a way that the mapping of file names to file IDs changes, then you should invoke CM.synchronize(). Otherwise CM might get confused.
The purpose of "group" is now to give structure to a "library". Under the new scheme, each group has a unique "owner" which is either some library or the "toplevel". If the owner is a library, then you must specify that library in parentheses after the "group" keyword.
To quickly convert existing code to work with the new scheme,it may be easier to ignore the "group" issue and use "library" exclusively. However, groups _are_ an important concept as soon as you begin creating your own stable libraries.
Lal George Last modified: Thu Dec 2 18:14:31 EST 1999