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View of /archive/mlsave.11/VERSION

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Revision 4054 - (download) (annotate)
Wed Feb 4 20:42:42 2015 UTC (4 years, 4 months ago) by dbm
File size: 8595 byte(s)
Initial import of archive (of early versions of sml/nj)
Standard ML of New Jersey, Version 11
From (internal) Version 10

Added abstract syntax constructor for signature declarations.  Fixed a bug
in the interactive system where a semicolon following a signature caused
an error.  Top-level processing and some printing routines had to be
changed to cope.

Added the signature ERRORMSG.

Got rid of two redundant matches, got rid of the CONST constructor from
access (it was never used), general cleanup.

Moved internals to the Control structure.

Improved implode.

Minor cleanup; file assumed that Byte_array was open.

Added a structure Timer to System which has a few timing structures.
A new function was added to Assembly to support it.  The garbage
collector sequence was modified to keep track of the total time spent
in garbage collection; this is used to throw out time spent in garbage

The garbage timer was returning the wrong time--there was a rounding error,
and moveback was not included in major garbage collection time.

Implemented open_append for v9.

_export1_v was added to prim, and _export1_v was added to Assembly.
export1 was added to General.  Commandline arguments are not yet implemented.

Cleanup: removed debug and debugStr from parse; moved debugLook and
debugCollect flags from env to control.

Moved CGoptions into Control.

Added system and cd to General; added a few fields to Assembly to do so.

Added sharing constraints and sharing checking (typing/sharing.sml and
util/union.sml are new).

{absyn/{bareabsyn.{sig,sml},printabsyn.sml}, typing/sigmatch.sml, parse/
Added "abstraction" declaration.  New abstract syntax constructur ABSdec.

Known bugs: (tyj)

system and cd may raise exceptions.

Problem with flushing streams on exit: we do our own buffering, so _exit
doesn't flush.  But how to get from the runtime code to Pervasives to
flush?  One possibility: a ref in Assembly, but communicating the opposite

On startup, an export1 executable should set std_out ttyflushing; again, this
must be done in Pervasives.  Also streams that were open before export
must now be closed.

Note timers will act strangely across exports.

On exit: streams.  On restart (from export): ttys; streams; timers.

- 432E432;
Error: Real constant out of range
- it;
val it = uncaught exception Boxity

Poor error message on:
- fun f hd::tl = 4;
Error: expected EQUAL, found ID (::)
Error: nonfix-identifier expected
Error: unbound variable bogus
Error: type error: operator and operand don't agree
operator : ((??*?? list) -> ?? list)
operand : (??*('x1911A list -> 'x1911A list))
  bogus :: tl
The "unbound variable bogus" is confusing.

"abstraction" is not implemented; as a result, byte_arrays are printed as
 strings, and streams are printed in their hidden form.

The behavior of the system when it reaches limits is sometimes bizarre.
For instance, on a Sun, if the system runs out of stack space it
will die with "Illegal instruction".  Note that the stack limit can
be changed with the limit command; and hopefully this bug will disappear
with the next version of the code generator.

Implode is stupid.

Unhoisted linked code seems broken.

Top level bindings should not report on exhaustiveness, but they do.

-          8.69169476570297E~309;	(* inaccurate real *)
> val it = 8.69169476570301E~309 : real
-          8.69169476570301E~309;	(* possibly a printing error? *)
> val it = 8.69169476570305E~309 : real

Exceptions do not print by name/value; only "-".  This cannot be fixed
 unless the runtime representation of exceptions is changed radically--
 it must be modified to include type information, and may not be
 worth the effort.
Also, a declaration "exception b = a" can be a bit deceiving; the runtime
 name of b will be that of a.  Fixing this would also require a significant
 change in the runtime format of exceptions.
What should the interactive system print when it catches an exception?  It
 knows about some exceptions like Float and Io_failure, so it could
 print their full values.  This would be confusing, though, since no
 other exceptions would be printed in full; a user would think there
 was something wrong with his exception when the name and not the value
 was printed.

Byte_array is open in the initial environment; it should be present but
 unopened.  Some of our source assumes it is open, though.

Notes: (tyj)

Printing of types needs to be cleaned up: <hidden> and paths are needed;
 type variables should be normalized to 'a, 'b, etc.; attention to
 precedence of "->", etc., would reduce the number of parens; it would be
 nice if the compiler spit out the signature of a structure as it was
 parsed or opened.
Should the compiler force the capitalization convention for constructor names
 as well as exception names?  Should it discourage all other capitalized values?
 Right now it only complains if an exception is uncapitalized.  Maybe it
 should complain if a capitalized variable is introduced in a pattern.
The construct "val _ =" turns up all the time, so the match compiler has
 been changed so that _ counts as a variable in a pattern (the "binding
 contains no variables" message won't turn up).  It would be nice to unhack
 this by providing a "do" declaration, since "val _"  isn't very intuitive.
Maybe testcase_string should be changed.  Right now an equality function
 is generated for each case.  Perhaps inline string equality; can the
 offset be found by name?
Printing of infixes is slightly hacked because of the way infix is
 implemented; fixity is a lexical/syntactic property with scope rather than
 a property of a dataconstructor/value.
It might be a good idea to have a stringdepth parameter in the printing
 routines which would control the max length to print string values.
Functions mentioned in documentation but missing in the compiler:
    execute; system; export; import; export1; math functions.

Notes: (dbm)

Bad error messages

* "unbound str in str"

* message for circular type unification, as in "fun f x = f;"


* New versions of bootEnv functions do not leave signatures of pervasive
  and its substructures defined.

* Identification of string and byte_array types (need abstraction implemented)
* In printing specs in signature match error messages, IND is printed in types.

* uncaught exception Notfound from bogus type identifier in a signature
  (e.g. "infodf" in envaccess.sig).

* no checking for duplicated specifications in signatures.  this should be done
  when building the signature symbol table

* signatures for Pervasives and its substructures are thrown away after
  booting (bootenv).

* simultaneous structure and functor declarations not implemented

* functor declarations require result signatures

Optimizations and simplifications

* stupid expansion of simple function definitions into case form (FUNdec
  in Absyn).  E.g.

    fun f x = x  ==>
    val rec f = fn arg => case arg of x => x

* fix type abbreviations so that in simple cases the name is bound to the
  old type constructor (or a copy) rather than to type function.

* string hashing primitive in Assembly


* eliminate nonexhaustive/redundant matches

* binding functions in EnvAccess are inconsistent in what they return.  Some
  return unit, others the variable that is bound.

* move useful debugging flags into control, eliminate unnecessary debugging 

* change the name of SymbolTable structure to something like Symbols or SymbolSet.

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