Hello all,
When looking through the different hash table implementations available
(Guile, SRFI-69, and RNRS) I found a useful SRFI-69 procedure that had
no equivalent in Guile's native hash table API: alist->hash-table.
This patch is an attempt to add that. It works for all four types of
hash tables: equal?, eq?, eqv? and custom.
- Dave
>From e303098404321cbe2b978d526ee2737137a5d5b1 Mon Sep 17 00:00:00 2001
From: David Thompson <dthomps...@worcester.edu>
Date: Sat, 19 Oct 2013 22:43:37 -0400
Subject: [PATCH] Add procedures to convert alists into hash tables.
* libguile/hashtab.c (scm_alist_to_hash_table, scm_alist_to_hashq_table,
scm_alist_to_hashv_table, scm_alist_to_hashx_table): Add the
equivalent of SRFI-69's alist->hash-table procedure for the native
hash table implementation.
* test-suite/tests/hash.test ("alist->hash-table"): Add tests.
* doc/ref/api-compound.texi (alist->hash-table): Add docs.
---
doc/ref/api-compound.texi | 18 ++++++++++++++
libguile/hashtab.c | 61 ++++++++++++++++++++++++++++++++++++++++++++++
libguile/hashtab.h | 6 +++++
test-suite/tests/hash.test | 27 ++++++++++++++++++++
4 files changed, 112 insertions(+)
diff --git a/doc/ref/api-compound.texi b/doc/ref/api-compound.texi
index 94e0145..9794e28 100644
--- a/doc/ref/api-compound.texi
+++ b/doc/ref/api-compound.texi
@@ -3829,6 +3829,24 @@ then it can use @var{size} to avoid rehashing when initial entries are
added.
@end deffn
+@deffn {Scheme Procedure} alist->hash-table alist [size]
+@deffnx {Scheme Procedure} alist->hashq-table alist [size]
+@deffnx {Scheme Procedure} alist->hashv-table alist [size]
+@deffnx {Scheme Procedure} alist->hashx-table hash assoc alist [size]
+@deffnx {C Function} scm_alist_to_hash_table (alist, size)
+@deffnx {C Function} scm_alist_to_hashq_table (alist, size)
+@deffnx {C Function} scm_alist_to_hashv_table (alist, size)
+@deffnx {C Function} scm_alist_to_hashx_table (alist, size)
+Convert @var{alist} into a hash table with minimum number of buckets
+@var{n}. When keys are repeated in @var{alist}, the leftmost association
+takes precedence.
+
+@example
+(alist->hash-table '((foo . 1) (bar . 2)))
+@end example
+
+@end deffn
+
@deffn {Scheme Procedure} hash-table? obj
@deffnx {C Function} scm_hash_table_p (obj)
Return @code{#t} if @var{obj} is a abstract hash table object.
diff --git a/libguile/hashtab.c b/libguile/hashtab.c
index 88cb199..c215269 100644
--- a/libguile/hashtab.c
+++ b/libguile/hashtab.c
@@ -423,6 +423,67 @@ SCM_DEFINE (scm_make_hash_table, "make-hash-table", 0, 1, 0,
}
#undef FUNC_NAME
+#define SCM_ALIST_TO_HASH_TABLE(alist, n, hash_set_fn) \
+ SCM hash_table; \
+ SCM_VALIDATE_LIST (1, alist); \
+ hash_table = scm_make_hash_table (n); \
+ while (!scm_is_null (alist)) { \
+ SCM pair = SCM_CAR (alist); \
+ hash_set_fn (hash_table, scm_car (pair), scm_cdr (pair)); \
+ alist = SCM_CDR (alist); \
+ } \
+ return hash_table;
+
+SCM_DEFINE (scm_alist_to_hash_table, "alist->hash-table", 1, 1, 0,
+ (SCM alist, SCM n),
+ "Convert @var{alist} into a hash table with minimum number of "
+ "buckets @var{n}.")
+#define FUNC_NAME s_scm_alist_to_hash_table
+{
+ SCM_ALIST_TO_HASH_TABLE (alist, n, scm_hash_set_x);
+}
+#undef FUNC_NAME
+
+SCM_DEFINE (scm_alist_to_hashq_table, "alist->hashq-table", 1, 1, 0,
+ (SCM alist, SCM n),
+ "Convert @var{alist} into a hash table with minimum number of "
+ "buckets @var{n}.")
+#define FUNC_NAME s_scm_alist_to_hashq_table
+{
+ SCM_ALIST_TO_HASH_TABLE (alist, n, scm_hashq_set_x);
+}
+#undef FUNC_NAME
+
+SCM_DEFINE (scm_alist_to_hashv_table, "alist->hashv-table", 1, 1, 0,
+ (SCM alist, SCM n),
+ "Convert @var{alist} into a hash table with minimum number of "
+ "buckets @var{n}.")
+#define FUNC_NAME s_scm_alist_to_hashv_table
+{
+ SCM_ALIST_TO_HASH_TABLE (alist, n, scm_hashv_set_x);
+}
+#undef FUNC_NAME
+
+SCM_DEFINE (scm_alist_to_hashx_table, "alist->hashx-table", 3, 1, 0,
+ (SCM hash, SCM assoc, SCM alist, SCM n),
+ "Convert @var{alist} into a hash table with minimum number of "
+ "buckets @var{n}.")
+#define FUNC_NAME s_scm_alist_to_hashx_table
+{
+ SCM hash_table;
+ SCM_VALIDATE_LIST (3, alist);
+ hash_table = scm_make_hash_table (n);
+
+ while (!scm_is_null (alist)) {
+ SCM pair = SCM_CAR (alist);
+ scm_hashx_set_x (hash, assoc, hash_table, scm_car (pair), scm_cdr (pair));
+ alist = SCM_CDR (alist);
+ }
+
+ return hash_table;
+}
+#undef FUNC_NAME
+
/* The before-gc C hook only runs if GC_set_start_callback is available,
so if not, fall back on a finalizer-based implementation. */
static int
diff --git a/libguile/hashtab.h b/libguile/hashtab.h
index dcebcb8..da4f28c 100644
--- a/libguile/hashtab.h
+++ b/libguile/hashtab.h
@@ -101,6 +101,12 @@ SCM_API SCM scm_make_weak_key_hash_table (SCM k);
SCM_API SCM scm_make_weak_value_hash_table (SCM k);
SCM_API SCM scm_make_doubly_weak_hash_table (SCM k);
+SCM_API SCM scm_alist_to_hash_table (SCM alist, SCM n);
+SCM_API SCM scm_alist_to_hashq_table (SCM alist, SCM n);
+SCM_API SCM scm_alist_to_hashv_table (SCM alist, SCM n);
+SCM_API SCM scm_alist_to_hashx_table (SCM hash, SCM assoc,
+ SCM alist, SCM n);
+
SCM_API SCM scm_hash_table_p (SCM h);
SCM_API SCM scm_weak_key_hash_table_p (SCM h);
SCM_API SCM scm_weak_value_hash_table_p (SCM h);
diff --git a/test-suite/tests/hash.test b/test-suite/tests/hash.test
index 3bd4004..b09c0b8 100644
--- a/test-suite/tests/hash.test
+++ b/test-suite/tests/hash.test
@@ -81,6 +81,33 @@
(write (make-hash-table 100)))))))
;;;
+;;; alist->hash-table
+;;;
+
+(with-test-prefix
+ "alist->hash-table"
+
+ ;; equal? hash table
+ (pass-if (let ((table (alist->hash-table '(("foo" . 1) ("bar" . 2)))))
+ (and (= (hash-ref table "foo") 1)
+ (= (hash-ref table "bar") 2))))
+
+ ;; eq? hash table
+ (pass-if (let ((table (alist->hashq-table '((foo . 1) (bar . 2)))))
+ (and (= (hashq-ref table 'foo) 1)
+ (= (hashq-ref table 'bar) 2))))
+
+ ;; eqv? hash table
+ (pass-if (let ((table (alist->hashv-table '((1 . 1) (2 . 2)))))
+ (and (= (hashv-ref table 1) 1)
+ (= (hashv-ref table 2) 2))))
+
+ ;; custom hash table
+ (pass-if (let ((table (alist->hashx-table hash assoc '((foo . 1) (bar . 2)))))
+ (and (= (hashx-ref hash assoc table 'foo) 1)
+ (= (hashx-ref hash assoc table 'bar) 2)))))
+
+;;;
;;; usual set and reference
;;;
--
1.8.4.rc3
