Re: [Gcl-devel] Re: possible lisp reader enhancement/modification

[Matt Kaufmann]

Hi, Camm --

Thank you very much.  Sorry I didn't think to mention this before, but for the
purpose I have in mind I'd like whitespace after the :: to be ignored by the
reader, so for example the following would work.

  >'lisp:: a

  LISP::||

  >
  Error: The variable LISP::A is unbound.
  Fast links are on: do (si::use-fast-links nil) for debugging
  Error signalled by EVAL.
  Broken at EVAL.  Type :H for Help.
  >>:q

  Top level.
  >

Here are some more examples (probably you can just ignore them).  I don't so
much need whitespace ignored before :: and a symbol, but rather, between :: and
an open paren.

  >'lisp::(a b user::c)

  (LISP::A LISP::B C)

  >'lisp::  (a b user::c)

  LISP::||

  >
  Error: The function LISP::A is undefined.
  Fast links are on: do (si::use-fast-links nil) for debugging
  Error signalled by EVAL.
  Broken at EVAL.  Type :H for Help.
  >>:q

  Top level.
  >'lisp::
  (a b user::c)

  LISP::||

  >
  Error: The function LISP::A is undefined.
  Fast links are on: do (si::use-fast-links nil) for debugging
  Error signalled by EVAL.
  Broken at EVAL.  Type :H for Help.
  >>:q

  Top level.
  >(quote lisp::(a b user::c))

  (LISP::A LISP::B C)

  >(quote lisp::
    (a b user::c))

  Error: Too many arguments.
  Fast links are on: do (si::use-fast-links nil) for debugging
  Error signalled by QUOTE.
  Broken at QUOTE.  Type :H for Help.
  >>

Is this an easy fix for you that you're willing to make?

Thanks --
-- Matt
   Cc: address@hidden, address@hidden
   From: Camm Maguire <address@hidden>
   Date: 09 Jul 2003 11:49:11 -0400
   User-Agent: Gnus/5.09 (Gnus v5.9.0) Emacs/21.2
   Content-Type: text/plain; charset=us-ascii

   Greetings!  OK, here is take three -- this should ensure that the
   stack is popped on input error somewhere in the list:

   =============================================================================
   diff -u -r1.14 read.d
   --- read.d   26 Feb 2003 22:21:37 -0000      1.14
   +++ read.d   9 Jul 2003 15:45:45 -0000
   @@ -392,6 +392,11 @@
           Read_object(in) reads an object from stream in.
           This routine corresponds to COMMON Lisp function READ.
    */
   +
   +/* FIXME What should this be? Apparently no reliable way to use value stack 
*/ 
   +#define MAX_PACKAGE_STACK 100 
   +static object P0[MAX_PACKAGE_STACK],*PP0=P0;
   +
    object
    read_object(in)
    object in;
   @@ -428,6 +433,7 @@
           });
                   a = cat(c);
           } while (a == cat_whitespace);
   +    if (c->ch.ch_code==')' && PP0>P0) PP0--;
           delimiting_char = vs_head;
           if (delimiting_char != OBJNULL && c == delimiting_char) {
                   delimiting_char = OBJNULL;
   @@ -587,6 +593,17 @@
                   token->st.st_fillp = length - (colon + 2);
           } else
                   p = current_package();
   +    /* FIXME Perhaps one of these is redundant */
   +    if (c->ch.ch_code=='(' && !token->st.st_fillp && colon_type) {
   +      if (PP0-P0>=MAX_PACKAGE_STACK)
   +        FEerror("Too many nested package specifiers",0);
   +      *PP0++=p;
   +      x=read_object(in);
   +      vs_reset;
   +      return (x);
   +    }
   +    if (PP0>P0 && !colon_type)
   +      p=PP0[-1];
           vs_push(p);
           x = intern(token, p);
           vs_push(x);
   =============================================================================
   (sid)address@hidden:/fix/t1/camm/gcl/unixport$ ./saved_gcl
   GCL (GNU Common Lisp)  (2.5.3) Tue Jul  8 17:07:32 UTC 2003
   Licensed under GNU Library General Public License
   Dedicated to the memory of W. Schelter

   Use (help) to get some basic information on how to use GCL.

   >(read)
   (quote (q lisp::(a b si::c d) e))

   '(Q (LISP::A LISP::B SYSTEM::C LISP::D) E)

   >(read)
   (quote (q lisp::(a b si::c . . d) e))

   Error: Two dots appeared consecutively.
   Fast links are on: do (si::use-fast-links nil) for debugging
   Error signalled by READ.
   Broken at READ.  Type :H for Help.
   >>
   Error: The variable LISP::D is unbound.
   Fast links are on: do (si::use-fast-links nil) for debugging
   Error signalled by EVALHOOK.
   Backtrace: system:universal-error-handler > EVALHOOK

   Broken at READ.
   >>
   Error: The variable E is unbound.
   Fast links are on: do (si::use-fast-links nil) for debugging
   Error signalled by EVALHOOK.
   Backtrace: system:universal-error-handler > EVALHOOK

   Broken at READ.
   >>(quote (q lisp::(a b si::c d) e))

   (Q (LISP::A LISP::B SYSTEM::C LISP::D) E)
   >>:q

   Top level.
   >(quote (q lisp::(a b si::c d) e))

   (Q (LISP::A LISP::B SYSTEM::C LISP::D) E)

   >(by)
   =============================================================================

   Take care,

   Matt Kaufmann <address@hidden> writes:

   > Thanks, Camm!  Rob Sumners put your mods in and built GCL with them.  He 
looked
   > at your code and described your approach, so I tried an example with nested
   > package prefixes.  Unfortunately, it didn't do what I expected, which is 
to use
   > the closest package prefix:
   > 
   > GCL:
   > 
   > >'lisp::(a b user::c)
   > 
   > (LISP::A LISP::B LISP::C)
   > 
   > >
   > 
   > Allegro CL:
   > 
   > CL-USER(1): 'lisp::(a b user::c)
   > (COMMON-LISP::A COMMON-LISP::B C)
   > CL-USER(2): 
   > 
   > Maybe an easy fix for you?
   > 
   > Thanks --
   > -- Matt
   >    cc: address@hidden
   >    From: Camm Maguire <address@hidden>
   >    Date: 08 Jul 2003 12:52:30 -0400
   >    User-Agent: Gnus/5.09 (Gnus v5.9.0) Emacs/21.2
   >    Content-Type: text/plain; charset=us-ascii
   > 
   >    Greetings!  Given Paul's analysis, let's put in this feature.  You
   >    might want to try this patch:
   > 
   >    diff -u -r1.14 read.d
   >    --- read.d      26 Feb 2003 22:21:37 -0000      1.14
   >    +++ read.d      8 Jul 2003 16:47:32 -0000
   >    @@ -392,6 +392,9 @@
   >       Read_object(in) reads an object from stream in.
   >       This routine corresponds to COMMON Lisp function READ.
   >     */
   >    +
   >    +static object p0=Cnil;
   >    +
   >     object
   >     read_object(in)
   >     object in;
   >    @@ -587,6 +590,15 @@
   >               token->st.st_fillp = length - (colon + 2);
   >       } else
   >               p = current_package();
   >    +       if (c->ch.ch_code=='(' && !token->st.st_fillp && colon_type) {
   >    +         p0=p;
   >    +         x=read_object(in);
   >    +         p0=Cnil;
   >    +         vs_reset;
   >    +         return (x);
   >    +       }
   >    +       if (p0!=Cnil)
   >    +         p=p0;
   >       vs_push(p);
   >       x = intern(token, p);
   >       vs_push(x);
   > 
   > 
   >    
=============================================================================
   >    (sid)address@hidden:/fix/t1/camm/gcl/unixport$ ./saved_gcl
   >    GCL (GNU Common Lisp)  (2.5.3) Tue Jul  8 15:22:09 UTC 2003
   >    Licensed under GNU Library General Public License
   >    Dedicated to the memory of W. Schelter
   > 
   >    Use (help) to get some basic information on how to use GCL.
   > 
   >    >(quote lisp::(a b c))
   > 
   >    (LISP::A LISP::B LISP::C)
   > 
   >    >(quote (a b c))
   > 
   >    (A B C)
   > 
   >    >(by)
   >    
=============================================================================
   > 
   >    I'll test this and commit to the unstable branch if all is well.
   >    Comments welcome, as always.
   > 
   >    Take care,
   > 
   >    Matt Kaufmann <address@hidden> writes:
   > 
   >    > Thanks for the quick reply!
   >    > 
   >    > -- Matt
   >    >    cc: address@hidden, "Paul F. Dietz" <address@hidden>
   >    >    From: Camm Maguire <address@hidden>
   >    >    Date: 02 Jul 2003 15:42:16 -0400
   >    >    User-Agent: Gnus/5.09 (Gnus v5.9.0) Emacs/21.2
   >    >    Content-Type: text/plain; charset=us-ascii
   >    > 
   >    >    Greetings, and thanks for your suggestion!
   >    > 
   >    >    I'm forwarding this to the list to solicit opinions from our ANSI
   >    >    standard experts on whether such a change would be permissible in 
ANSI
   >    >    common lisp.  Comments?
   >    > 
   >    >    Take care,
   >    > 
   >    >    Matt Kaufmann <address@hidden> writes:
   >    > 
   >    >    > Hi --
   >    >    > 
   >    >    > I wonder if it would be possible to modify the GCL reader so 
that package
   >    >    > prefixes can apply to lists, not just symbols.  Here's an 
example of what I
   >    >    > mean.
   >    >    > 
   >    >    >   >'lisp::(a b)
   >    >    > 
   >    >    >   LISP::||
   >    >    > 
   >    >    >   >
   >    >    >   Error: The function A is undefined.
   >    >    >   Fast links are on: do (si::use-fast-links nil) for debugging
   >    >    >   Error signalled by EVAL.
   >    >    >   Broken at EVAL.  Type :H for Help.
   >    >    >   >>
   >    >    > 
   >    >    > Here is the corresponding log for Allegro Common Lisp.
   >    >    > 
   >    >    >   CL-USER(2): 'lisp::(a b)
   >    >    >   (COMMON-LISP::A COMMON-LISP::B)
   >    >    >   CL-USER(3): 
   >    >    > 
   >    >    > I'm pretty sure that there's no CLtL requirement to make such a 
change.  It's
   >    >    > even possible that GCL does this right and Allegro CL does it 
wrong.  But
   >    >    > anyhow, I thought I'd ask, because it would be very handy to 
have such a
   >    >    > capability in GCL (it could affect which Lisp is used under ACL2 
at AMD).
   >    >    > 
   >    >    > Thanks --
   >    >    > -- Matt
   >    >    > 
   >    >    > 
   >    >    > 
   >    > 
   >    >    -- 
   >    >    Camm Maguire                                               
address@hidden
   >    >    
==========================================================================
   >    >    "The earth is but one country, and mankind its citizens."  --  
Baha'u'llah
   >    > 
   >    > 
   >    > 
   > 
   >    -- 
   >    Camm Maguire                                            address@hidden
   >    
==========================================================================
   >    "The earth is but one country, and mankind its citizens."  --  
Baha'u'llah
   > 
   > 
   > _______________________________________________
   > Gcl-devel mailing list
   > address@hidden
   > http://mail.gnu.org/mailman/listinfo/gcl-devel
   > 
   > 
   > 

   -- 
   Camm Maguire                                         address@hidden
   ==========================================================================
   "The earth is but one country, and mankind its citizens."  --  Baha'u'llah