[Guile-commits] 11/11: New functions (array-for-each-cell, array-for-each-cell-in-order)

[Daniel Llorens]

lloda pushed a commit to branch lloda-squash0
in repository guile.

commit a5bb9da6ea3f69a0e03329b94dcb3bf1c3315ed5
Author: Daniel Llorens 
Date:   Tue Sep 8 16:57:30 2015 +0200

New functions (array-for-each-cell, array-for-each-cell-in-order)

* libguile/array-map.c (scm_i_array_rebase, scm_array_for_each_cell):
  New functions. Export scm_array_for_each_cell() as
  (array-for-each-cell).

  (array-for-each-cell-in-order): Define additional export.

* libguile/array-map.h (scm_i_array_rebase, scm_array_for_each_cell):
  Add prototypes.

* doc/ref/api-compound.texi: New section 'Arrays as arrays of
  arrays'. Move the documentation for (array-from), (array-from*) and
  (array-amend!) in here. Add documentation for (array-for-each-cell).

* test-suite/tests/array-map.test: Renamed from
  test-suite/tests/ramap.test, fix module name. Add tests for
  (array-for-each-cell).

* test-suite/Makefile.am: Apply rename array-map.test -> ramap.test.

* doc/ref/api-compound.texi: Minor documentation fixes.
---
 doc/ref/api-compound.texi   |  169 ++-
 libguile/array-map.c|  260 ++-
 libguile/array-map.h|4 +
 libguile/arrays.c   |5 +-
 test-suite/Makefile.am  |2 +-
 test-suite/tests/{ramap.test => array-map.test} |   35 ++-
 6 files changed, 416 insertions(+), 59 deletions(-)

diff --git a/doc/ref/api-compound.texi b/doc/ref/api-compound.texi
index 6d1e118..936b495 100644
--- a/doc/ref/api-compound.texi
+++ b/doc/ref/api-compound.texi
@@ -1203,6 +1203,7 @@ dimensional arrays.
 * Array Syntax::
 * Array Procedures::
 * Shared Arrays::   
+* Arrays as arrays of arrays::
 * Accessing Arrays from C:: 
 @end menu
 
@@ -1682,24 +1683,91 @@ sample points are enough because @var{mapfunc} is 
linear.
 Return the element at @code{(idx @dots{})} in @var{array}.
 @end deffn
 
+
+@deffn {Scheme Procedure} shared-array-increments array
+@deffnx {C Function} scm_shared_array_increments (array)
+For each dimension, return the distance between elements in the root vector.
+@end deffn
+
+@deffn {Scheme Procedure} shared-array-offset array
+@deffnx {C Function} scm_shared_array_offset (array)
+Return the root vector index of the first element in the array.
+@end deffn
+
+@deffn {Scheme Procedure} shared-array-root array
+@deffnx {C Function} scm_shared_array_root (array)
+Return the root vector of a shared array.
+@end deffn
+
+@deffn {Scheme Procedure} array-contents array [strict]
+@deffnx {C Function} scm_array_contents (array, strict)
+If @var{array} may be @dfn{unrolled} into a one dimensional shared array
+without changing their order (last subscript changing fastest), then
+@code{array-contents} returns that shared array, otherwise it returns
+@code{#f}.  All arrays made by @code{make-array} and
+@code{make-typed-array} may be unrolled, some arrays made by
+@code{make-shared-array} may not be.
+
+If the optional argument @var{strict} is provided, a shared array will
+be returned only if its elements are stored internally contiguous in
+memory.
+@end deffn
+
+@deffn {Scheme Procedure} transpose-array array dim1 dim2 @dots{}
+@deffnx {C Function} scm_transpose_array (array, dimlist)
+Return an array sharing contents with @var{array}, but with
+dimensions arranged in a different order.  There must be one
+@var{dim} argument for each dimension of @var{array}.
+@var{dim1}, @var{dim2}, @dots{} should be integers between 0
+and the rank of the array to be returned.  Each integer in that
+range must appear at least once in the argument list.
+
+The values of @var{dim1}, @var{dim2}, @dots{} correspond to
+dimensions in the array to be returned, and their positions in the
+argument list to dimensions of @var{array}.  Several @var{dim}s
+may have the same value, in which case the returned array will
+have smaller rank than @var{array}.
+
+@lisp
+(transpose-array '#2((a b) (c d)) 1 0) @result{} #2((a c) (b d))
+(transpose-array '#2((a b) (c d)) 0 0) @result{} #1(a d)
+(transpose-array '#3(((a b c) (d e f)) ((1 2 3) (4 5 6))) 1 1 0) @result{}
+#2((a 4) (b 5) (c 6))
+@end lisp
+@end deffn
+
+@node Arrays as arrays of arrays
+@subsubsection Arrays as arrays of arrays
+
+The functions in this section allow you to treat an array of rank
+@math{n} as an array of lower rank @math{n-k} where the elements are
+themselves arrays (`cells') of rank @math{k}. This replicates some of
+the functionality of `enclosed arrays', a feature of old Guile that was
+removed before @w{version 2.0}. However, these functions do not require
+a special type and operate on any array.
+
+When we operate on an array in this way, we speak of the first @math{k}
+dimensions of the array as the @math{k}-`frame' of the array, while the

[Guile-commits] 11/11: New functions (array-for-each-cell, array-for-each-cell-in-order)

[Daniel Llorens]

lloda pushed a commit to branch lloda-squash0
in repository guile.

commit 018579ca292446d7130132a4223e37be43713f31
Author: Daniel Llorens 
Date:   Tue Sep 8 16:57:30 2015 +0200

New functions (array-for-each-cell, array-for-each-cell-in-order)

* libguile/array-map.c (scm_i_array_rebase, scm_array_for_each_cell):
  New functions. Export scm_array_for_each_cell() as
  (array-for-each-cell).

  (array-for-each-cell-in-order): Define additional export.

* libguile/array-map.h (scm_i_array_rebase, scm_array_for_each_cell):
  Add prototypes.

* doc/ref/api-compound.texi: New section 'Arrays as arrays of
  arrays'. Move the documentation for (array-from), (array-from*) and
  (array-amend!) in here. Add documentation for (array-for-each-cell).

* test-suite/tests/array-map.test: Renamed from
  test-suite/tests/ramap.test, fix module name. Add tests for
  (array-for-each-cell).

* test-suite/Makefile.am: Apply rename array-map.test -> ramap.test.

* doc/ref/api-compound.texi: Minor documentation fixes.
---
 doc/ref/api-compound.texi   |  169 ++-
 libguile/array-map.c|  260 ++-
 libguile/array-map.h|4 +
 libguile/arrays.c   |5 +-
 test-suite/Makefile.am  |2 +-
 test-suite/tests/{ramap.test => array-map.test} |   35 ++-
 6 files changed, 416 insertions(+), 59 deletions(-)

diff --git a/doc/ref/api-compound.texi b/doc/ref/api-compound.texi
index 6d1e118..936b495 100644
--- a/doc/ref/api-compound.texi
+++ b/doc/ref/api-compound.texi
@@ -1203,6 +1203,7 @@ dimensional arrays.
 * Array Syntax::
 * Array Procedures::
 * Shared Arrays::   
+* Arrays as arrays of arrays::
 * Accessing Arrays from C:: 
 @end menu
 
@@ -1682,24 +1683,91 @@ sample points are enough because @var{mapfunc} is 
linear.
 Return the element at @code{(idx @dots{})} in @var{array}.
 @end deffn
 
+
+@deffn {Scheme Procedure} shared-array-increments array
+@deffnx {C Function} scm_shared_array_increments (array)
+For each dimension, return the distance between elements in the root vector.
+@end deffn
+
+@deffn {Scheme Procedure} shared-array-offset array
+@deffnx {C Function} scm_shared_array_offset (array)
+Return the root vector index of the first element in the array.
+@end deffn
+
+@deffn {Scheme Procedure} shared-array-root array
+@deffnx {C Function} scm_shared_array_root (array)
+Return the root vector of a shared array.
+@end deffn
+
+@deffn {Scheme Procedure} array-contents array [strict]
+@deffnx {C Function} scm_array_contents (array, strict)
+If @var{array} may be @dfn{unrolled} into a one dimensional shared array
+without changing their order (last subscript changing fastest), then
+@code{array-contents} returns that shared array, otherwise it returns
+@code{#f}.  All arrays made by @code{make-array} and
+@code{make-typed-array} may be unrolled, some arrays made by
+@code{make-shared-array} may not be.
+
+If the optional argument @var{strict} is provided, a shared array will
+be returned only if its elements are stored internally contiguous in
+memory.
+@end deffn
+
+@deffn {Scheme Procedure} transpose-array array dim1 dim2 @dots{}
+@deffnx {C Function} scm_transpose_array (array, dimlist)
+Return an array sharing contents with @var{array}, but with
+dimensions arranged in a different order.  There must be one
+@var{dim} argument for each dimension of @var{array}.
+@var{dim1}, @var{dim2}, @dots{} should be integers between 0
+and the rank of the array to be returned.  Each integer in that
+range must appear at least once in the argument list.
+
+The values of @var{dim1}, @var{dim2}, @dots{} correspond to
+dimensions in the array to be returned, and their positions in the
+argument list to dimensions of @var{array}.  Several @var{dim}s
+may have the same value, in which case the returned array will
+have smaller rank than @var{array}.
+
+@lisp
+(transpose-array '#2((a b) (c d)) 1 0) @result{} #2((a c) (b d))
+(transpose-array '#2((a b) (c d)) 0 0) @result{} #1(a d)
+(transpose-array '#3(((a b c) (d e f)) ((1 2 3) (4 5 6))) 1 1 0) @result{}
+#2((a 4) (b 5) (c 6))
+@end lisp
+@end deffn
+
+@node Arrays as arrays of arrays
+@subsubsection Arrays as arrays of arrays
+
+The functions in this section allow you to treat an array of rank
+@math{n} as an array of lower rank @math{n-k} where the elements are
+themselves arrays (`cells') of rank @math{k}. This replicates some of
+the functionality of `enclosed arrays', a feature of old Guile that was
+removed before @w{version 2.0}. However, these functions do not require
+a special type and operate on any array.
+
+When we operate on an array in this way, we speak of the first @math{k}
+dimensions of the array as the @math{k}-`frame' of the array, while the

[Guile-commits] 11/11: New functions (array-for-each-cell, array-for-each-cell-in-order)

[Daniel Llorens]

lloda pushed a commit to branch lloda-squash0
in repository guile.

commit 8b49ec31081b37f12c3909801353f6bad4dfaffe
Author: Daniel Llorens 
Date:   Tue Sep 8 16:57:30 2015 +0200

New functions (array-for-each-cell, array-for-each-cell-in-order)

* libguile/array-map.c (scm_i_array_rebase, scm_array_for_each_cell):
  New functions. Export scm_array_for_each_cell() as
  (array-for-each-cell).

  (array-for-each-cell-in-order): Define additional export.

* libguile/array-map.h (scm_i_array_rebase, scm_array_for_each_cell):
  Add prototypes.

* doc/ref/api-compound.texi: New section 'Arrays as arrays of
  arrays'. Move the documentation for (array-from), (array-from*) and
  (array-amend!) in here. Add documentation for (array-for-each-cell).

* test-suite/tests/array-map.test: Renamed from
  test-suite/tests/ramap.test, fix module name. Add tests for
  (array-for-each-cell).

* test-suite/Makefile.am: Apply rename array-map.test -> ramap.test.

* doc/ref/api-compound.texi: Minor documentation fixes.
---
 doc/ref/api-compound.texi   |  169 ++-
 libguile/array-map.c|  260 ++-
 libguile/array-map.h|4 +
 libguile/arrays.c   |5 +-
 test-suite/Makefile.am  |2 +-
 test-suite/tests/{ramap.test => array-map.test} |   35 ++-
 6 files changed, 416 insertions(+), 59 deletions(-)

diff --git a/doc/ref/api-compound.texi b/doc/ref/api-compound.texi
index 6d1e118..936b495 100644
--- a/doc/ref/api-compound.texi
+++ b/doc/ref/api-compound.texi
@@ -1203,6 +1203,7 @@ dimensional arrays.
 * Array Syntax::
 * Array Procedures::
 * Shared Arrays::   
+* Arrays as arrays of arrays::
 * Accessing Arrays from C:: 
 @end menu
 
@@ -1682,24 +1683,91 @@ sample points are enough because @var{mapfunc} is 
linear.
 Return the element at @code{(idx @dots{})} in @var{array}.
 @end deffn
 
+
+@deffn {Scheme Procedure} shared-array-increments array
+@deffnx {C Function} scm_shared_array_increments (array)
+For each dimension, return the distance between elements in the root vector.
+@end deffn
+
+@deffn {Scheme Procedure} shared-array-offset array
+@deffnx {C Function} scm_shared_array_offset (array)
+Return the root vector index of the first element in the array.
+@end deffn
+
+@deffn {Scheme Procedure} shared-array-root array
+@deffnx {C Function} scm_shared_array_root (array)
+Return the root vector of a shared array.
+@end deffn
+
+@deffn {Scheme Procedure} array-contents array [strict]
+@deffnx {C Function} scm_array_contents (array, strict)
+If @var{array} may be @dfn{unrolled} into a one dimensional shared array
+without changing their order (last subscript changing fastest), then
+@code{array-contents} returns that shared array, otherwise it returns
+@code{#f}.  All arrays made by @code{make-array} and
+@code{make-typed-array} may be unrolled, some arrays made by
+@code{make-shared-array} may not be.
+
+If the optional argument @var{strict} is provided, a shared array will
+be returned only if its elements are stored internally contiguous in
+memory.
+@end deffn
+
+@deffn {Scheme Procedure} transpose-array array dim1 dim2 @dots{}
+@deffnx {C Function} scm_transpose_array (array, dimlist)
+Return an array sharing contents with @var{array}, but with
+dimensions arranged in a different order.  There must be one
+@var{dim} argument for each dimension of @var{array}.
+@var{dim1}, @var{dim2}, @dots{} should be integers between 0
+and the rank of the array to be returned.  Each integer in that
+range must appear at least once in the argument list.
+
+The values of @var{dim1}, @var{dim2}, @dots{} correspond to
+dimensions in the array to be returned, and their positions in the
+argument list to dimensions of @var{array}.  Several @var{dim}s
+may have the same value, in which case the returned array will
+have smaller rank than @var{array}.
+
+@lisp
+(transpose-array '#2((a b) (c d)) 1 0) @result{} #2((a c) (b d))
+(transpose-array '#2((a b) (c d)) 0 0) @result{} #1(a d)
+(transpose-array '#3(((a b c) (d e f)) ((1 2 3) (4 5 6))) 1 1 0) @result{}
+#2((a 4) (b 5) (c 6))
+@end lisp
+@end deffn
+
+@node Arrays as arrays of arrays
+@subsubsection Arrays as arrays of arrays
+
+The functions in this section allow you to treat an array of rank
+@math{n} as an array of lower rank @math{n-k} where the elements are
+themselves arrays (`cells') of rank @math{k}. This replicates some of
+the functionality of `enclosed arrays', a feature of old Guile that was
+removed before @w{version 2.0}. However, these functions do not require
+a special type and operate on any array.
+
+When we operate on an array in this way, we speak of the first @math{k}
+dimensions of the array as the @math{k}-`frame' of the array, while the

[Guile-commits] 11/11: New functions (array-for-each-cell, array-for-each-cell-in-order)

[Daniel Llorens]

lloda pushed a commit to branch lloda-squash0
in repository guile.

commit 0961c318034e109bb42aba301951496780673936
Author: Daniel Llorens 
Date:   Tue Sep 8 16:57:30 2015 +0200

New functions (array-for-each-cell, array-for-each-cell-in-order)

* libguile/array-map.c (scm_i_array_rebase, scm_array_for_each_cell):
  New functions. Export scm_array_for_each_cell() as
  (array-for-each-cell).

  (array-for-each-cell-in-order): Define additional export.

* libguile/array-map.h (scm_i_array_rebase, scm_array_for_each_cell):
  Add prototypes.

* doc/ref/api-compound.texi: New section 'Arrays as arrays of
  arrays'. Move the documentation for (array-from), (array-from*) and
  (array-amend!) in here. Add documentation for (array-for-each-cell).

* test-suite/tests/array-map.test: Renamed from
  test-suite/tests/ramap.test, fix module name. Add tests for
  (array-for-each-cell).

* test-suite/Makefile.am: Apply rename array-map.test -> ramap.test.

* doc/ref/api-compound.texi: Minor documentation fixes.
---
 doc/ref/api-compound.texi   |  169 ++-
 libguile/array-map.c|  260 ++-
 libguile/array-map.h|4 +
 libguile/arrays.c   |5 +-
 test-suite/Makefile.am  |2 +-
 test-suite/tests/{ramap.test => array-map.test} |   35 ++-
 6 files changed, 416 insertions(+), 59 deletions(-)

diff --git a/doc/ref/api-compound.texi b/doc/ref/api-compound.texi
index 6d1e118..936b495 100644
--- a/doc/ref/api-compound.texi
+++ b/doc/ref/api-compound.texi
@@ -1203,6 +1203,7 @@ dimensional arrays.
 * Array Syntax::
 * Array Procedures::
 * Shared Arrays::   
+* Arrays as arrays of arrays::
 * Accessing Arrays from C:: 
 @end menu
 
@@ -1682,24 +1683,91 @@ sample points are enough because @var{mapfunc} is 
linear.
 Return the element at @code{(idx @dots{})} in @var{array}.
 @end deffn
 
+
+@deffn {Scheme Procedure} shared-array-increments array
+@deffnx {C Function} scm_shared_array_increments (array)
+For each dimension, return the distance between elements in the root vector.
+@end deffn
+
+@deffn {Scheme Procedure} shared-array-offset array
+@deffnx {C Function} scm_shared_array_offset (array)
+Return the root vector index of the first element in the array.
+@end deffn
+
+@deffn {Scheme Procedure} shared-array-root array
+@deffnx {C Function} scm_shared_array_root (array)
+Return the root vector of a shared array.
+@end deffn
+
+@deffn {Scheme Procedure} array-contents array [strict]
+@deffnx {C Function} scm_array_contents (array, strict)
+If @var{array} may be @dfn{unrolled} into a one dimensional shared array
+without changing their order (last subscript changing fastest), then
+@code{array-contents} returns that shared array, otherwise it returns
+@code{#f}.  All arrays made by @code{make-array} and
+@code{make-typed-array} may be unrolled, some arrays made by
+@code{make-shared-array} may not be.
+
+If the optional argument @var{strict} is provided, a shared array will
+be returned only if its elements are stored internally contiguous in
+memory.
+@end deffn
+
+@deffn {Scheme Procedure} transpose-array array dim1 dim2 @dots{}
+@deffnx {C Function} scm_transpose_array (array, dimlist)
+Return an array sharing contents with @var{array}, but with
+dimensions arranged in a different order.  There must be one
+@var{dim} argument for each dimension of @var{array}.
+@var{dim1}, @var{dim2}, @dots{} should be integers between 0
+and the rank of the array to be returned.  Each integer in that
+range must appear at least once in the argument list.
+
+The values of @var{dim1}, @var{dim2}, @dots{} correspond to
+dimensions in the array to be returned, and their positions in the
+argument list to dimensions of @var{array}.  Several @var{dim}s
+may have the same value, in which case the returned array will
+have smaller rank than @var{array}.
+
+@lisp
+(transpose-array '#2((a b) (c d)) 1 0) @result{} #2((a c) (b d))
+(transpose-array '#2((a b) (c d)) 0 0) @result{} #1(a d)
+(transpose-array '#3(((a b c) (d e f)) ((1 2 3) (4 5 6))) 1 1 0) @result{}
+#2((a 4) (b 5) (c 6))
+@end lisp
+@end deffn
+
+@node Arrays as arrays of arrays
+@subsubsection Arrays as arrays of arrays
+
+The functions in this section allow you to treat an array of rank
+@math{n} as an array of lower rank @math{n-k} where the elements are
+themselves arrays (`cells') of rank @math{k}. This replicates some of
+the functionality of `enclosed arrays', a feature of old Guile that was
+removed before @w{version 2.0}. However, these functions do not require
+a special type and operate on any array.
+
+When we operate on an array in this way, we speak of the first @math{k}
+dimensions of the array as the @math{k}-`frame' of the array, while the

[Guile-commits] 11/11: New functions (array-for-each-cell, array-for-each-cell-in-order)

[Daniel Llorens]

lloda pushed a commit to branch lloda-squash0
in repository guile.

commit ed383e94e45557b40536853c0fd4545ba0dfba80
Author: Daniel Llorens 
Date:   Tue Sep 8 16:57:30 2015 +0200

New functions (array-for-each-cell, array-for-each-cell-in-order)

* libguile/array-map.c (scm_i_array_rebase, scm_array_for_each_cell):
  New functions. Export scm_array_for_each_cell() as
  (array-for-each-cell).

  (array-for-each-cell-in-order): Define additional export.

* libguile/array-map.h (scm_i_array_rebase, scm_array_for_each_cell):
  Add prototypes.

* doc/ref/api-compound.texi: New section 'Arrays as arrays of
  arrays'. Move the documentation for (array-from), (array-from*) and
  (array-amend!) in here. Add documentation for (array-for-each-cell).

* test-suite/tests/array-map.test: Renamed from
  test-suite/tests/ramap.test, fix module name. Add tests for
  (array-for-each-cell).

* test-suite/Makefile.am: Apply rename array-map.test -> ramap.test.

* doc/ref/api-compound.texi: Minor documentation fixes.
---
 doc/ref/api-compound.texi   |  169 ++-
 libguile/array-map.c|  260 ++-
 libguile/array-map.h|4 +
 libguile/arrays.c   |5 +-
 test-suite/Makefile.am  |2 +-
 test-suite/tests/{ramap.test => array-map.test} |   35 ++-
 6 files changed, 416 insertions(+), 59 deletions(-)

diff --git a/doc/ref/api-compound.texi b/doc/ref/api-compound.texi
index d17c4bf..bc2c98b 100644
--- a/doc/ref/api-compound.texi
+++ b/doc/ref/api-compound.texi
@@ -1203,6 +1203,7 @@ dimensional arrays.
 * Array Syntax::
 * Array Procedures::
 * Shared Arrays::   
+* Arrays as arrays of arrays::
 * Accessing Arrays from C:: 
 @end menu
 
@@ -1682,24 +1683,91 @@ sample points are enough because @var{mapfunc} is 
linear.
 Return the element at @code{(idx @dots{})} in @var{array}.
 @end deffn
 
+
+@deffn {Scheme Procedure} shared-array-increments array
+@deffnx {C Function} scm_shared_array_increments (array)
+For each dimension, return the distance between elements in the root vector.
+@end deffn
+
+@deffn {Scheme Procedure} shared-array-offset array
+@deffnx {C Function} scm_shared_array_offset (array)
+Return the root vector index of the first element in the array.
+@end deffn
+
+@deffn {Scheme Procedure} shared-array-root array
+@deffnx {C Function} scm_shared_array_root (array)
+Return the root vector of a shared array.
+@end deffn
+
+@deffn {Scheme Procedure} array-contents array [strict]
+@deffnx {C Function} scm_array_contents (array, strict)
+If @var{array} may be @dfn{unrolled} into a one dimensional shared array
+without changing their order (last subscript changing fastest), then
+@code{array-contents} returns that shared array, otherwise it returns
+@code{#f}.  All arrays made by @code{make-array} and
+@code{make-typed-array} may be unrolled, some arrays made by
+@code{make-shared-array} may not be.
+
+If the optional argument @var{strict} is provided, a shared array will
+be returned only if its elements are stored internally contiguous in
+memory.
+@end deffn
+
+@deffn {Scheme Procedure} transpose-array array dim1 dim2 @dots{}
+@deffnx {C Function} scm_transpose_array (array, dimlist)
+Return an array sharing contents with @var{array}, but with
+dimensions arranged in a different order.  There must be one
+@var{dim} argument for each dimension of @var{array}.
+@var{dim1}, @var{dim2}, @dots{} should be integers between 0
+and the rank of the array to be returned.  Each integer in that
+range must appear at least once in the argument list.
+
+The values of @var{dim1}, @var{dim2}, @dots{} correspond to
+dimensions in the array to be returned, and their positions in the
+argument list to dimensions of @var{array}.  Several @var{dim}s
+may have the same value, in which case the returned array will
+have smaller rank than @var{array}.
+
+@lisp
+(transpose-array '#2((a b) (c d)) 1 0) @result{} #2((a c) (b d))
+(transpose-array '#2((a b) (c d)) 0 0) @result{} #1(a d)
+(transpose-array '#3(((a b c) (d e f)) ((1 2 3) (4 5 6))) 1 1 0) @result{}
+#2((a 4) (b 5) (c 6))
+@end lisp
+@end deffn
+
+@node Arrays as arrays of arrays
+@subsubsection Arrays as arrays of arrays
+
+The functions in this section allow you to treat an array of rank
+@math{n} as an array of lower rank @math{n-k} where the elements are
+themselves arrays (`cells') of rank @math{k}. This replicates some of
+the functionality of `enclosed arrays', a feature of old Guile that was
+removed before @w{version 2.0}. However, these functions do not require
+a special type and operate on any array.
+
+When we operate on an array in this way, we speak of the first @math{k}
+dimensions of the array as the @math{k}-`frame' of the array, while the