[Guile-commits] 10/11: New functions array-from, array-from*, array-amend!
lloda pushed a commit to branch lloda-squash0
in repository guile.
commit 1945cdf491c669ce54f94b90fd083f71642d1b2e
Author: Daniel Llorens
Date: Wed Feb 11 16:44:21 2015 +0100
New functions array-from, array-from*, array-amend!
* libguile/arrays.h (scm_array_from, scm_array_from_s,
scm_array_amend_x): New declarations.
* libguile/arrays.c (scm_array_from, scm_array_from_s,
scm_array_amend_x): New functions, export as array-from, array-from*,
array-amend!.
* test-suite/tests/arrays.test: Tests for array-from, array-from*,
array-amend!.
* doc/ref/api-compound.texi: Document array-from, array-from*,
array-amend!.
---
doc/ref/api-compound.texi| 105
libguile/arrays.c| 158 ++
libguile/arrays.h|6 ++
test-suite/tests/arrays.test | 109 +
4 files changed, 378 insertions(+)
diff --git a/doc/ref/api-compound.texi b/doc/ref/api-compound.texi
index 97aaba3..6d1e118 100644
--- a/doc/ref/api-compound.texi
+++ b/doc/ref/api-compound.texi
@@ -1676,6 +1676,111 @@ base and stride for new array indices in @var{oldarray}
data. A few
sample points are enough because @var{mapfunc} is linear.
@end deffn
+
+@deffn {Scheme Procedure} array-ref array idx @dots{}
+@deffnx {C Function} scm_array_ref (array, idxlist)
+Return the element at @code{(idx @dots{})} in @var{array}.
+@end deffn
+
+@deffn {Scheme Procedure} array-from array idx @dots{}
+@deffnx {C Function} scm_array_from (array, idxlist)
+If the length of @var{idxlist} equals the rank @math{n} of
+@var{array}, return the element at @code{(idx @dots{})}, just like
+@code{(array-ref array idx @dots{})}. If, however, the length @math{k}
+of @var{idxlist} is shorter than @math{n}, then return the shared
+@math{(n-k)}-rank prefix cell of @var{array} given by @var{idxlist}.
+
+For example:
+
+@example
+@lisp
+(array-from #2((a b) (c d)) 0) @result{} #(a b)
+(array-from #2((a b) (c d)) 1) @result{} #(c d)
+(array-from #2((a b) (c d)) 1 1) @result{} d
+(array-from #2((a b) (c d))) @result{} #2((a b) (c d))
+@end lisp
+@end example
+
+@code{(apply array-from array indices)} is equivalent to
+
+@lisp
+(let ((len (length indices)))
+ (if (= (array-rank a) len)
+(apply array-ref a indices)
+(apply make-shared-array a
+ (lambda t (append indices t))
+ (drop (array-dimensions a) len
+@end lisp
+
+The name `from' comes from the J language.
+@end deffn
+
+@deffn {Scheme Procedure} array-from* array idx @dots{}
+@deffnx {C Function} scm_array_from_s (array, idxlist)
+Like @code{(array-from array idx @dots{})}, but return a 0-rank shared
+array if the length of @var{idxlist} matches the rank of
+@var{array}. This can be useful when using @var{ARRAY} as destination
+of copies.
+
+Compare:
+
+@example
+@lisp
+(array-from #2((a b) (c d)) 1 1) @result{} d
+(array-from* #2((a b) (c d)) 1) @result{} #0(d)
+(define a (make-array 'a 2 2))
+(array-fill! (array-from* a 1 1) 'b)
+a @result{} #2((a a) (a b)).
+(array-fill! (array-from a 1 1) 'b) @result{} error: not an array
+@end lisp
+@end example
+
+@code{(apply array-from* array indices)} is equivalent to
+
+@lisp
+(apply make-shared-array a
+ (lambda t (append indices t))
+ (drop (array-dimensions a) (length indices)))
+@end lisp
+@end deffn
+
+
+@deffn {Scheme Procedure} array-amend! array x idx @dots{}
+@deffnx {C Function} scm_array_amend_x (array, x, idxlist)
+If the length of @var{idxlist} equals the rank @math{n} of
+@var{array}, set the element at @code{(idx @dots{})} of @var{array} to
+@var{x}, just like @code{(array-set! array x idx @dots{})}. If,
+however, the length @math{k} of @var{idxlist} is shorter than
+@math{n}, then copy the @math{(n-k)}-rank array @var{x}
+into @math{(n-k)}-rank prefix cell of @var{array} given by
+@var{idxlist}. In this case, the last @math{(n-k)} dimensions of
+@var{array} and the dimensions of @var{x} must match exactly.
+
+This function returns the modified @var{array}.
+
+For example:
+
+@example
+@lisp
+(array-amend! (make-array 'a 2 2) b 1 1) @result{} #2((a a) (a b))
+(array-amend! (make-array 'a 2 2) #(x y) 1) @result{} #2((a a) (x y))
+@end lisp
+@end example
+
+@code{(apply array-amend! array x indices)} is equivalent to
+
+@lisp
+(let ((len (length indices)))
+ (if (= (array-rank array) len)
+(apply array-set! array x indices)
+(array-copy! x (apply array-from array indices)))
+ array)
+@end lisp
+
+The name `amend' comes from the J language.
+@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.
diff --git a/libguile/arrays.c b/libguile/arrays.c
index fb522e1..273c48b 100644
--- a/libguile/arrays.c
+++ b/libguile/arrays.c
@@ -416,6 +416,164 @@ SCM_DEFINE (scm_make_shared_array, "make-shared-arr
[Guile-commits] 10/11: New functions array-from, array-from*, array-amend!
lloda pushed a commit to branch lloda-squash0
in repository guile.
commit 4f00886066ec0e7b690dce347c19f99fa2101aa2
Author: Daniel Llorens
Date: Wed Feb 11 16:44:21 2015 +0100
New functions array-from, array-from*, array-amend!
* libguile/arrays.h (scm_array_from, scm_array_from_s,
scm_array_amend_x): New declarations.
* libguile/arrays.c (scm_array_from, scm_array_from_s,
scm_array_amend_x): New functions, export as array-from, array-from*,
array-amend!.
* test-suite/tests/arrays.test: Tests for array-from, array-from*,
array-amend!.
* doc/ref/api-compound.texi: Document array-from, array-from*,
array-amend!.
---
doc/ref/api-compound.texi| 105
libguile/arrays.c| 158 ++
libguile/arrays.h|6 ++
test-suite/tests/arrays.test | 109 +
4 files changed, 378 insertions(+)
diff --git a/doc/ref/api-compound.texi b/doc/ref/api-compound.texi
index 97aaba3..6d1e118 100644
--- a/doc/ref/api-compound.texi
+++ b/doc/ref/api-compound.texi
@@ -1676,6 +1676,111 @@ base and stride for new array indices in @var{oldarray}
data. A few
sample points are enough because @var{mapfunc} is linear.
@end deffn
+
+@deffn {Scheme Procedure} array-ref array idx @dots{}
+@deffnx {C Function} scm_array_ref (array, idxlist)
+Return the element at @code{(idx @dots{})} in @var{array}.
+@end deffn
+
+@deffn {Scheme Procedure} array-from array idx @dots{}
+@deffnx {C Function} scm_array_from (array, idxlist)
+If the length of @var{idxlist} equals the rank @math{n} of
+@var{array}, return the element at @code{(idx @dots{})}, just like
+@code{(array-ref array idx @dots{})}. If, however, the length @math{k}
+of @var{idxlist} is shorter than @math{n}, then return the shared
+@math{(n-k)}-rank prefix cell of @var{array} given by @var{idxlist}.
+
+For example:
+
+@example
+@lisp
+(array-from #2((a b) (c d)) 0) @result{} #(a b)
+(array-from #2((a b) (c d)) 1) @result{} #(c d)
+(array-from #2((a b) (c d)) 1 1) @result{} d
+(array-from #2((a b) (c d))) @result{} #2((a b) (c d))
+@end lisp
+@end example
+
+@code{(apply array-from array indices)} is equivalent to
+
+@lisp
+(let ((len (length indices)))
+ (if (= (array-rank a) len)
+(apply array-ref a indices)
+(apply make-shared-array a
+ (lambda t (append indices t))
+ (drop (array-dimensions a) len
+@end lisp
+
+The name `from' comes from the J language.
+@end deffn
+
+@deffn {Scheme Procedure} array-from* array idx @dots{}
+@deffnx {C Function} scm_array_from_s (array, idxlist)
+Like @code{(array-from array idx @dots{})}, but return a 0-rank shared
+array if the length of @var{idxlist} matches the rank of
+@var{array}. This can be useful when using @var{ARRAY} as destination
+of copies.
+
+Compare:
+
+@example
+@lisp
+(array-from #2((a b) (c d)) 1 1) @result{} d
+(array-from* #2((a b) (c d)) 1) @result{} #0(d)
+(define a (make-array 'a 2 2))
+(array-fill! (array-from* a 1 1) 'b)
+a @result{} #2((a a) (a b)).
+(array-fill! (array-from a 1 1) 'b) @result{} error: not an array
+@end lisp
+@end example
+
+@code{(apply array-from* array indices)} is equivalent to
+
+@lisp
+(apply make-shared-array a
+ (lambda t (append indices t))
+ (drop (array-dimensions a) (length indices)))
+@end lisp
+@end deffn
+
+
+@deffn {Scheme Procedure} array-amend! array x idx @dots{}
+@deffnx {C Function} scm_array_amend_x (array, x, idxlist)
+If the length of @var{idxlist} equals the rank @math{n} of
+@var{array}, set the element at @code{(idx @dots{})} of @var{array} to
+@var{x}, just like @code{(array-set! array x idx @dots{})}. If,
+however, the length @math{k} of @var{idxlist} is shorter than
+@math{n}, then copy the @math{(n-k)}-rank array @var{x}
+into @math{(n-k)}-rank prefix cell of @var{array} given by
+@var{idxlist}. In this case, the last @math{(n-k)} dimensions of
+@var{array} and the dimensions of @var{x} must match exactly.
+
+This function returns the modified @var{array}.
+
+For example:
+
+@example
+@lisp
+(array-amend! (make-array 'a 2 2) b 1 1) @result{} #2((a a) (a b))
+(array-amend! (make-array 'a 2 2) #(x y) 1) @result{} #2((a a) (x y))
+@end lisp
+@end example
+
+@code{(apply array-amend! array x indices)} is equivalent to
+
+@lisp
+(let ((len (length indices)))
+ (if (= (array-rank array) len)
+(apply array-set! array x indices)
+(array-copy! x (apply array-from array indices)))
+ array)
+@end lisp
+
+The name `amend' comes from the J language.
+@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.
diff --git a/libguile/arrays.c b/libguile/arrays.c
index fb522e1..273c48b 100644
--- a/libguile/arrays.c
+++ b/libguile/arrays.c
@@ -416,6 +416,164 @@ SCM_DEFINE (scm_make_shared_array, "make-shared-arr
[Guile-commits] 10/11: New functions array-from, array-from*, array-amend!
lloda pushed a commit to branch lloda-squash0
in repository guile.
commit afbb28b3b3508c791ec1219e54770cd8f4ddec09
Author: Daniel Llorens
Date: Wed Feb 11 16:44:21 2015 +0100
New functions array-from, array-from*, array-amend!
* libguile/arrays.h (scm_array_from, scm_array_from_s,
scm_array_amend_x): New declarations.
* libguile/arrays.c (scm_array_from, scm_array_from_s,
scm_array_amend_x): New functions, export as array-from, array-from*,
array-amend!.
* test-suite/tests/arrays.test: Tests for array-from, array-from*,
array-amend!.
* doc/ref/api-compound.texi: Document array-from, array-from*,
array-amend!.
---
doc/ref/api-compound.texi| 105
libguile/arrays.c| 158 ++
libguile/arrays.h|6 ++
test-suite/tests/arrays.test | 109 +
4 files changed, 378 insertions(+)
diff --git a/doc/ref/api-compound.texi b/doc/ref/api-compound.texi
index 97aaba3..6d1e118 100644
--- a/doc/ref/api-compound.texi
+++ b/doc/ref/api-compound.texi
@@ -1676,6 +1676,111 @@ base and stride for new array indices in @var{oldarray}
data. A few
sample points are enough because @var{mapfunc} is linear.
@end deffn
+
+@deffn {Scheme Procedure} array-ref array idx @dots{}
+@deffnx {C Function} scm_array_ref (array, idxlist)
+Return the element at @code{(idx @dots{})} in @var{array}.
+@end deffn
+
+@deffn {Scheme Procedure} array-from array idx @dots{}
+@deffnx {C Function} scm_array_from (array, idxlist)
+If the length of @var{idxlist} equals the rank @math{n} of
+@var{array}, return the element at @code{(idx @dots{})}, just like
+@code{(array-ref array idx @dots{})}. If, however, the length @math{k}
+of @var{idxlist} is shorter than @math{n}, then return the shared
+@math{(n-k)}-rank prefix cell of @var{array} given by @var{idxlist}.
+
+For example:
+
+@example
+@lisp
+(array-from #2((a b) (c d)) 0) @result{} #(a b)
+(array-from #2((a b) (c d)) 1) @result{} #(c d)
+(array-from #2((a b) (c d)) 1 1) @result{} d
+(array-from #2((a b) (c d))) @result{} #2((a b) (c d))
+@end lisp
+@end example
+
+@code{(apply array-from array indices)} is equivalent to
+
+@lisp
+(let ((len (length indices)))
+ (if (= (array-rank a) len)
+(apply array-ref a indices)
+(apply make-shared-array a
+ (lambda t (append indices t))
+ (drop (array-dimensions a) len
+@end lisp
+
+The name `from' comes from the J language.
+@end deffn
+
+@deffn {Scheme Procedure} array-from* array idx @dots{}
+@deffnx {C Function} scm_array_from_s (array, idxlist)
+Like @code{(array-from array idx @dots{})}, but return a 0-rank shared
+array if the length of @var{idxlist} matches the rank of
+@var{array}. This can be useful when using @var{ARRAY} as destination
+of copies.
+
+Compare:
+
+@example
+@lisp
+(array-from #2((a b) (c d)) 1 1) @result{} d
+(array-from* #2((a b) (c d)) 1) @result{} #0(d)
+(define a (make-array 'a 2 2))
+(array-fill! (array-from* a 1 1) 'b)
+a @result{} #2((a a) (a b)).
+(array-fill! (array-from a 1 1) 'b) @result{} error: not an array
+@end lisp
+@end example
+
+@code{(apply array-from* array indices)} is equivalent to
+
+@lisp
+(apply make-shared-array a
+ (lambda t (append indices t))
+ (drop (array-dimensions a) (length indices)))
+@end lisp
+@end deffn
+
+
+@deffn {Scheme Procedure} array-amend! array x idx @dots{}
+@deffnx {C Function} scm_array_amend_x (array, x, idxlist)
+If the length of @var{idxlist} equals the rank @math{n} of
+@var{array}, set the element at @code{(idx @dots{})} of @var{array} to
+@var{x}, just like @code{(array-set! array x idx @dots{})}. If,
+however, the length @math{k} of @var{idxlist} is shorter than
+@math{n}, then copy the @math{(n-k)}-rank array @var{x}
+into @math{(n-k)}-rank prefix cell of @var{array} given by
+@var{idxlist}. In this case, the last @math{(n-k)} dimensions of
+@var{array} and the dimensions of @var{x} must match exactly.
+
+This function returns the modified @var{array}.
+
+For example:
+
+@example
+@lisp
+(array-amend! (make-array 'a 2 2) b 1 1) @result{} #2((a a) (a b))
+(array-amend! (make-array 'a 2 2) #(x y) 1) @result{} #2((a a) (x y))
+@end lisp
+@end example
+
+@code{(apply array-amend! array x indices)} is equivalent to
+
+@lisp
+(let ((len (length indices)))
+ (if (= (array-rank array) len)
+(apply array-set! array x indices)
+(array-copy! x (apply array-from array indices)))
+ array)
+@end lisp
+
+The name `amend' comes from the J language.
+@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.
diff --git a/libguile/arrays.c b/libguile/arrays.c
index fb522e1..273c48b 100644
--- a/libguile/arrays.c
+++ b/libguile/arrays.c
@@ -416,6 +416,164 @@ SCM_DEFINE (scm_make_shared_array, "make-shared-arr
[Guile-commits] 10/11: New functions array-from, array-from*, array-amend!
lloda pushed a commit to branch lloda-squash0
in repository guile.
commit 62eff47035db83ddf4ffa3505d02c6be6b27b27b
Author: Daniel Llorens
Date: Wed Feb 11 16:44:21 2015 +0100
New functions array-from, array-from*, array-amend!
* libguile/arrays.h (scm_array_from, scm_array_from_s,
scm_array_amend_x): New declarations.
* libguile/arrays.c (scm_array_from, scm_array_from_s,
scm_array_amend_x): New functions, export as array-from, array-from*,
array-amend!.
* test-suite/tests/arrays.test: Tests for array-from, array-from*,
array-amend!.
* doc/ref/api-compound.texi: Document array-from, array-from*,
array-amend!.
---
doc/ref/api-compound.texi| 105
libguile/arrays.c| 158 ++
libguile/arrays.h|6 ++
test-suite/tests/arrays.test | 109 +
4 files changed, 378 insertions(+)
diff --git a/doc/ref/api-compound.texi b/doc/ref/api-compound.texi
index 97aaba3..6d1e118 100644
--- a/doc/ref/api-compound.texi
+++ b/doc/ref/api-compound.texi
@@ -1676,6 +1676,111 @@ base and stride for new array indices in @var{oldarray}
data. A few
sample points are enough because @var{mapfunc} is linear.
@end deffn
+
+@deffn {Scheme Procedure} array-ref array idx @dots{}
+@deffnx {C Function} scm_array_ref (array, idxlist)
+Return the element at @code{(idx @dots{})} in @var{array}.
+@end deffn
+
+@deffn {Scheme Procedure} array-from array idx @dots{}
+@deffnx {C Function} scm_array_from (array, idxlist)
+If the length of @var{idxlist} equals the rank @math{n} of
+@var{array}, return the element at @code{(idx @dots{})}, just like
+@code{(array-ref array idx @dots{})}. If, however, the length @math{k}
+of @var{idxlist} is shorter than @math{n}, then return the shared
+@math{(n-k)}-rank prefix cell of @var{array} given by @var{idxlist}.
+
+For example:
+
+@example
+@lisp
+(array-from #2((a b) (c d)) 0) @result{} #(a b)
+(array-from #2((a b) (c d)) 1) @result{} #(c d)
+(array-from #2((a b) (c d)) 1 1) @result{} d
+(array-from #2((a b) (c d))) @result{} #2((a b) (c d))
+@end lisp
+@end example
+
+@code{(apply array-from array indices)} is equivalent to
+
+@lisp
+(let ((len (length indices)))
+ (if (= (array-rank a) len)
+(apply array-ref a indices)
+(apply make-shared-array a
+ (lambda t (append indices t))
+ (drop (array-dimensions a) len
+@end lisp
+
+The name `from' comes from the J language.
+@end deffn
+
+@deffn {Scheme Procedure} array-from* array idx @dots{}
+@deffnx {C Function} scm_array_from_s (array, idxlist)
+Like @code{(array-from array idx @dots{})}, but return a 0-rank shared
+array if the length of @var{idxlist} matches the rank of
+@var{array}. This can be useful when using @var{ARRAY} as destination
+of copies.
+
+Compare:
+
+@example
+@lisp
+(array-from #2((a b) (c d)) 1 1) @result{} d
+(array-from* #2((a b) (c d)) 1) @result{} #0(d)
+(define a (make-array 'a 2 2))
+(array-fill! (array-from* a 1 1) 'b)
+a @result{} #2((a a) (a b)).
+(array-fill! (array-from a 1 1) 'b) @result{} error: not an array
+@end lisp
+@end example
+
+@code{(apply array-from* array indices)} is equivalent to
+
+@lisp
+(apply make-shared-array a
+ (lambda t (append indices t))
+ (drop (array-dimensions a) (length indices)))
+@end lisp
+@end deffn
+
+
+@deffn {Scheme Procedure} array-amend! array x idx @dots{}
+@deffnx {C Function} scm_array_amend_x (array, x, idxlist)
+If the length of @var{idxlist} equals the rank @math{n} of
+@var{array}, set the element at @code{(idx @dots{})} of @var{array} to
+@var{x}, just like @code{(array-set! array x idx @dots{})}. If,
+however, the length @math{k} of @var{idxlist} is shorter than
+@math{n}, then copy the @math{(n-k)}-rank array @var{x}
+into @math{(n-k)}-rank prefix cell of @var{array} given by
+@var{idxlist}. In this case, the last @math{(n-k)} dimensions of
+@var{array} and the dimensions of @var{x} must match exactly.
+
+This function returns the modified @var{array}.
+
+For example:
+
+@example
+@lisp
+(array-amend! (make-array 'a 2 2) b 1 1) @result{} #2((a a) (a b))
+(array-amend! (make-array 'a 2 2) #(x y) 1) @result{} #2((a a) (x y))
+@end lisp
+@end example
+
+@code{(apply array-amend! array x indices)} is equivalent to
+
+@lisp
+(let ((len (length indices)))
+ (if (= (array-rank array) len)
+(apply array-set! array x indices)
+(array-copy! x (apply array-from array indices)))
+ array)
+@end lisp
+
+The name `amend' comes from the J language.
+@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.
diff --git a/libguile/arrays.c b/libguile/arrays.c
index fb522e1..273c48b 100644
--- a/libguile/arrays.c
+++ b/libguile/arrays.c
@@ -416,6 +416,164 @@ SCM_DEFINE (scm_make_shared_array, "make-shared-arr
[Guile-commits] 10/11: New functions array-from, array-from*, array-amend!
lloda pushed a commit to branch lloda-squash0
in repository guile.
commit a1e57225689af768fbab06dcbce43360a299eaaa
Author: Daniel Llorens
Date: Wed Feb 11 16:44:21 2015 +0100
New functions array-from, array-from*, array-amend!
* libguile/arrays.h (scm_array_from, scm_array_from_s,
scm_array_amend_x): New declarations.
* libguile/arrays.c (scm_array_from, scm_array_from_s,
scm_array_amend_x): New functions, export as array-from, array-from*,
array-amend!.
* test-suite/tests/arrays.test: Tests for array-from, array-from*,
array-amend!.
* doc/ref/api-compound.texi: Document array-from, array-from*,
array-amend!.
---
doc/ref/api-compound.texi| 105
libguile/arrays.c| 158 ++
libguile/arrays.h|6 ++
test-suite/tests/arrays.test | 109 +
4 files changed, 378 insertions(+)
diff --git a/doc/ref/api-compound.texi b/doc/ref/api-compound.texi
index cc9eef4..d17c4bf 100644
--- a/doc/ref/api-compound.texi
+++ b/doc/ref/api-compound.texi
@@ -1676,6 +1676,111 @@ base and stride for new array indices in @var{oldarray}
data. A few
sample points are enough because @var{mapfunc} is linear.
@end deffn
+
+@deffn {Scheme Procedure} array-ref array idx @dots{}
+@deffnx {C Function} scm_array_ref (array, idxlist)
+Return the element at @code{(idx @dots{})} in @var{array}.
+@end deffn
+
+@deffn {Scheme Procedure} array-from array idx @dots{}
+@deffnx {C Function} scm_array_from (array, idxlist)
+If the length of @var{idxlist} equals the rank @math{n} of
+@var{array}, return the element at @code{(idx @dots{})}, just like
+@code{(array-ref array idx @dots{})}. If, however, the length @math{k}
+of @var{idxlist} is shorter than @math{n}, then return the shared
+@math{(n-k)}-rank prefix cell of @var{array} given by @var{idxlist}.
+
+For example:
+
+@example
+@lisp
+(array-from #2((a b) (c d)) 0) @result{} #(a b)
+(array-from #2((a b) (c d)) 1) @result{} #(c d)
+(array-from #2((a b) (c d)) 1 1) @result{} d
+(array-from #2((a b) (c d))) @result{} #2((a b) (c d))
+@end lisp
+@end example
+
+@code{(apply array-from array indices)} is equivalent to
+
+@lisp
+(let ((len (length indices)))
+ (if (= (array-rank a) len)
+(apply array-ref a indices)
+(apply make-shared-array a
+ (lambda t (append indices t))
+ (drop (array-dimensions a) len
+@end lisp
+
+The name `from' comes from the J language.
+@end deffn
+
+@deffn {Scheme Procedure} array-from* array idx @dots{}
+@deffnx {C Function} scm_array_from_s (array, idxlist)
+Like @code{(array-from array idx @dots{})}, but return a 0-rank shared
+array if the length of @var{idxlist} matches the rank of
+@var{array}. This can be useful when using @var{ARRAY} as destination
+of copies.
+
+Compare:
+
+@example
+@lisp
+(array-from #2((a b) (c d)) 1 1) @result{} d
+(array-from* #2((a b) (c d)) 1) @result{} #0(d)
+(define a (make-array 'a 2 2))
+(array-fill! (array-from* a 1 1) 'b)
+a @result{} #2((a a) (a b)).
+(array-fill! (array-from a 1 1) 'b) @result{} error: not an array
+@end lisp
+@end example
+
+@code{(apply array-from* array indices)} is equivalent to
+
+@lisp
+(apply make-shared-array a
+ (lambda t (append indices t))
+ (drop (array-dimensions a) (length indices)))
+@end lisp
+@end deffn
+
+
+@deffn {Scheme Procedure} array-amend! array x idx @dots{}
+@deffnx {C Function} scm_array_amend_x (array, x, idxlist)
+If the length of @var{idxlist} equals the rank @math{n} of
+@var{array}, set the element at @code{(idx @dots{})} of @var{array} to
+@var{x}, just like @code{(array-set! array x idx @dots{})}. If,
+however, the length @math{k} of @var{idxlist} is shorter than
+@math{n}, then copy the @math{(n-k)}-rank array @var{x}
+into @math{(n-k)}-rank prefix cell of @var{array} given by
+@var{idxlist}. In this case, the last @math{(n-k)} dimensions of
+@var{array} and the dimensions of @var{x} must match exactly.
+
+This function returns the modified @var{array}.
+
+For example:
+
+@example
+@lisp
+(array-amend! (make-array 'a 2 2) b 1 1) @result{} #2((a a) (a b))
+(array-amend! (make-array 'a 2 2) #(x y) 1) @result{} #2((a a) (x y))
+@end lisp
+@end example
+
+@code{(apply array-amend! array x indices)} is equivalent to
+
+@lisp
+(let ((len (length indices)))
+ (if (= (array-rank array) len)
+(apply array-set! array x indices)
+(array-copy! x (apply array-from array indices)))
+ array)
+@end lisp
+
+The name `amend' comes from the J language.
+@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.
diff --git a/libguile/arrays.c b/libguile/arrays.c
index fb522e1..273c48b 100644
--- a/libguile/arrays.c
+++ b/libguile/arrays.c
@@ -416,6 +416,164 @@ SCM_DEFINE (scm_make_shared_array, "make-shared-arr
