[Sbcl-devel] Compiling with CLISP

[Dave M. <da...@id...>]

The CLISP maintainers have recently added MAKE-LOAD-FORM, so I've
tried over the last couple of days to get it to compile SBCL.  I've
encountered a number of problems, but compilation gets further than
when Martin Atzmueller last reported his progress.  However, CLISP
still cannot complete the make-host-1.sh script.

The problems that I encountered:

- some uses of DEFCONSTANT should be inside (EVAL-WHEN
  (:compile-toplevel) ...) forms, since the constant is used in reader
  macros later on

- keywords are not accepted in DEFSTRUCT :include forms for the names
  of inherited slots. e.g.

  (defstruct (derived
	     (:include struct-with-slot-named-variable
		       (:variable 'new-default))))
                        ^^^^^^^^^
  should be

  (defstruct (derived
	     (:include struct-with-slot-named-variable
		       (variable 'new-default))))
                        ^^^^^^^^
  I think CLISP conforms to ANSI on this.

- CLISP doesn't like the idiom where DEFSTRUCT slot-initforms
  reference bindings defined in the constructor declaration. e.g.

  (defstruct (test
             (:constructor make-test (vara)))
    vara
    (varb (+ vara 10)))

  should be re-written as the more portable

  (defstruct (test
             (:constructor make-test (vara &aux (varb (+ vara 10)))))
    vara varb)

  Thanks to Kent Pitman for pointing to this portable alternative.

- the reader macro issue that Martin mentioned is because SBCL reader
  macro functions return two values, but ANSI says they should return
  0 or 1 value.  The macros in src/code/backq.lisp return two values.
  The second value doesn't seem to be used in SBCL's reader, so I
  changed them.


I got past all of these problems.  I haven't tried recompiling SBCL
(using SBCL) yet, but I think the changes I made so far should be OK
as they are. I'll do the recompile and send a diff in the next couple
of days.

Two more serious problems:

- CLISP doesn't implement PPRINT-LOGICAL-BLOCK.  So far, I have been
  able to ignore this problem by setting
  *{load,compile}-{verbose,print}* to nil, thereby avoiding the need
  to attempt a call to this undefined function.

- CLISP generates the following error:

Compiling file /home/dave/packages/sbcl-work1/src/code/force-delayed-defbangstructs.lisp ...

Compilation of file /home/dave/packages/sbcl-work1/src/code/force-delayed-defbangstructs.lisp is finished.
0 errors, 0 warnings
;; Loading file obj/from-host/src/code/force-delayed-defbangstructs.lisp-obj ...
*** - VECTOR-PUSH-EXTEND works only on adjustable arrays, not on #(#<UNKNOWN-TYPE NULL> #<ARRAY-TYPE SIMPLE-STRING>)

  From stepping through sb!kernel::force-delayed-def!structs, I know
  that the error is generated when processing the PRIM-OBJECT-SLOT
  structure, but I don't know why it happens.  I'm not sure whether
  SBCL or CLISP is to blame, and I'm at a loss about how to debug
  further.

-Dave