Different approach: optional arguments on hash-isec and hash-uni allow

for more flexible joining of data from the hash tables.

* eval.c (eval_init): Remove hash_guni and hash_gisec. Change
registration for hash_uni and hash_isec to three arguments with
one optional.

* hash.c (hash_uni): Third parameter introduced, join_func.
The default behavior changes: in the two argument case,
clashing keys prefer the value from hash1 rather than hash2.
For this reason, we now iterate over hash2 first, then hash1.
(hash_guni): Removed.
(hash_isec): Third parameter introduced, join_func.
(hash_gisec): Removed.

* hash.h (hash_uni, hash_isec): Declarations updated.
(hash_guni, hash_gisec): Delarations removed.

* txr.1: Documentation updated.

1 files changed, 2 insertions, 4 deletions

diff --git a/hash.h b/hash.h
index 89048457..52783d37 100644
--- a/hash.h
+++ b/hash.h
@@ -53,11 +53,9 @@ val hash_keys(val hash);
 val hash_values(val hash);
 val hash_pairs(val hash);
 val hash_alist(val hash);
-val hash_uni(val hash1, val hash2);
-val hash_guni(val hash1, val hash2);
+val hash_uni(val hash1, val hash2, val join_func);
 val hash_diff(val hash1, val hash2);
-val hash_isec(val hash1, val hash2);
-val hash_gisec(val hash1, val hash2);
+val hash_isec(val hash1, val hash2, val join_func);
 val hash_update(val hash, val fun);
 
 void hash_process_weak(void);