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[Emacs-diffs] master 82b9efc: Minor simplifications and doc for records
From: |
Paul Eggert |
Subject: |
[Emacs-diffs] master 82b9efc: Minor simplifications and doc for records |
Date: |
Tue, 4 Apr 2017 17:08:00 -0400 (EDT) |
branch: master
commit 82b9efc869dddcbd5677867b84b20ae155b5b9da
Author: Paul Eggert <address@hidden>
Commit: Paul Eggert <address@hidden>
Minor simplifications and doc for records
* doc/lispref/records.texi (Records): Mention size limit.
* etc/NEWS: Mention records.
* src/alloc.c (allocate_pseudovector, allocate_record):
Prefer 'PSEUDOVECTOR_SIZE_MASK' to its definiens.
(allocate_record): Check arg range here, not in callers, as this
simplifies the code. Use allocate_vectorlike instead of
allocate_vector, to avoid duplicate runtime tests.
(Fmake_record, record): Don't mention PSEUDOVECTOR_SIZE_BITS in
the doc string, as it is not visible to the user.
(Fmake_record, record, Fcopy_record):
Prefer make_lisp_ptr to XSETVECTOR.
(record): Broaden memcpy to copy the type, too.
---
doc/lispref/records.texi | 6 +++--
etc/NEWS | 6 +++++
src/alloc.c | 67 ++++++++++++++----------------------------------
3 files changed, 29 insertions(+), 50 deletions(-)
diff --git a/doc/lispref/records.texi b/doc/lispref/records.texi
index 9a5d900..a6c560c 100644
--- a/doc/lispref/records.texi
+++ b/doc/lispref/records.texi
@@ -14,8 +14,10 @@ instances.
Internally, a record object is much like a vector; its slots can be
accessed using @code{aref}. However, the first slot is used to hold
-its type as returned by @code{type-of}. Like arrays, records use
-zero-origin indexing: the first slot has index 0.
+its type as returned by @code{type-of}. Also, in the current
+implementation records can have at most 4096 slots, whereas vectors
+can be much larger. Like arrays, records use zero-origin indexing:
+the first slot has index 0.
The printed representation of records is @samp{#s} followed by a
list specifying the contents. The first list element must be the
diff --git a/etc/NEWS b/etc/NEWS
index fc07656..8b17f16 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -840,6 +840,12 @@ instead of its first.
* Lisp Changes in Emacs 26.1
+++
+** Emacs now supports records for user-defined types, via the new
+functions 'copy-record', 'make-record', 'record', and 'recordp'.
+Records are now used internally to represent cl-defstruct and defclass
+instances, for example.
+
++++
** 'save-some-buffers' now uses 'save-some-buffers-default-predicate'
to decide which buffers to ask about, if the PRED argument is nil.
The default value of 'save-some-buffers-default-predicate' is nil,
diff --git a/src/alloc.c b/src/alloc.c
index 5024b12..a58824f 100644
--- a/src/alloc.c
+++ b/src/alloc.c
@@ -3371,7 +3371,7 @@ allocate_pseudovector (int memlen, int lisplen,
eassert (0 <= tag && tag <= PVEC_FONT);
eassert (0 <= lisplen && lisplen <= zerolen && zerolen <= memlen);
eassert (memlen - lisplen <= (1 << PSEUDOVECTOR_REST_BITS) - 1);
- eassert (lisplen <= (1 << PSEUDOVECTOR_SIZE_BITS) - 1);
+ eassert (lisplen <= PSEUDOVECTOR_SIZE_MASK);
/* Only the first LISPLEN slots will be traced normally by the GC. */
memclear (v->contents, zerolen * word_size);
@@ -3393,16 +3393,17 @@ allocate_buffer (void)
}
-/* Allocate a new record with COUNT slots. Return NULL if COUNT is
- too large. */
+/* Allocate a record with COUNT slots. COUNT must be positive, and
+ includes the type slot. */
static struct Lisp_Vector *
-allocate_record (int count)
+allocate_record (EMACS_INT count)
{
- if (count >= (1 << PSEUDOVECTOR_SIZE_BITS))
- return NULL;
-
- struct Lisp_Vector *p = allocate_vector (count);
+ if (count > PSEUDOVECTOR_SIZE_MASK)
+ error ("Attempt to allocate a record of %"pI"d slots; max is %d",
+ count, PSEUDOVECTOR_SIZE_MASK);
+ struct Lisp_Vector *p = allocate_vectorlike (count);
+ p->header.size = count;
XSETPVECTYPE (p, PVEC_RECORD);
return p;
}
@@ -3411,53 +3412,29 @@ allocate_record (int count)
DEFUN ("make-record", Fmake_record, Smake_record, 3, 3, 0,
doc: /* Create a new record.
TYPE is its type as returned by `type-of'. SLOTS is the number of
-slots, each initialized to INIT. The number of slots, including the
-type slot, must fit in PSEUDOVECTOR_SIZE_BITS. */)
+non-type slots, each initialized to INIT. */)
(Lisp_Object type, Lisp_Object slots, Lisp_Object init)
{
- Lisp_Object record;
- ptrdiff_t size, i;
- struct Lisp_Vector *p;
-
CHECK_NATNUM (slots);
-
- size = XFASTINT (slots) + 1;
- p = allocate_record (size);
- if (p == NULL)
- error ("Attempt to allocate a record of %"pD"d slots; max is %d",
- size, (1 << PSEUDOVECTOR_SIZE_BITS) - 1);
-
+ EMACS_INT size = XFASTINT (slots) + 1;
+ struct Lisp_Vector *p = allocate_record (size);
p->contents[0] = type;
- for (i = 1; i < size; i++)
+ for (ptrdiff_t i = 1; i < size; i++)
p->contents[i] = init;
-
- XSETVECTOR (record, p);
- return record;
+ return make_lisp_ptr (p, Lisp_Vectorlike);
}
DEFUN ("record", Frecord, Srecord, 1, MANY, 0,
doc: /* Create a new record.
TYPE is its type as returned by `type-of'. SLOTS is used to
-initialize the record slots with shallow copies of the arguments. The
-number of slots, including the type slot, must fit in
-PSEUDOVECTOR_SIZE_BITS.
+initialize the record slots with shallow copies of the arguments.
usage: (record TYPE &rest SLOTS) */)
(ptrdiff_t nargs, Lisp_Object *args)
{
struct Lisp_Vector *p = allocate_record (nargs);
- if (p == NULL)
- error ("Attempt to allocate a record of %"pD"d slots; max is %d",
- nargs, (1 << PSEUDOVECTOR_SIZE_BITS) - 1);
-
- Lisp_Object type = args[0];
- Lisp_Object record;
-
- p->contents[0] = type;
- memcpy (p->contents + 1, args + 1, (nargs - 1) * sizeof *args);
-
- XSETVECTOR (record, p);
- return record;
+ memcpy (p->contents, args, nargs * sizeof *args);
+ return make_lisp_ptr (p, Lisp_Vectorlike);
}
@@ -3466,17 +3443,11 @@ DEFUN ("copy-record", Fcopy_record, Scopy_record, 1, 1,
0,
(Lisp_Object record)
{
CHECK_RECORD (record);
- struct Lisp_Vector *src = XVECTOR (record);
ptrdiff_t size = ASIZE (record) & PSEUDOVECTOR_SIZE_MASK;
struct Lisp_Vector *new = allocate_record (size);
- if (new == NULL)
- error ("Attempt to allocate a record of %"pD"d slots; max is %d",
- size, (1 << PSEUDOVECTOR_SIZE_BITS) - 1);
-
- memcpy (&(new->contents[0]), &(src->contents[0]),
+ memcpy (new->contents, XVECTOR (record)->contents,
size * sizeof (Lisp_Object));
- XSETVECTOR (record, new);
- return record;
+ return make_lisp_ptr (new, Lisp_Vectorlike);
}
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