postgres.git / summary / log / commit / refs
commit ff9398052df511e7789b697e1be3bd940d45d74a
Author: Tom Lane <tgl@sss.pgh.pa.us>
Date: Mon Apr 10 17:51:29 2017 +0000
Improve castNode notation by introducing list-extraction-specific variants.
This extends the castNode() notation introduced by commit 5bcab1114 to
provide, in one step, extraction of a list cell's pointer and coercion to
a concrete node type. For example, "lfirst_node(Foo, lc)" is the same
as "castNode(Foo, lfirst(lc))". Almost half of the uses of castNode
that have appeared so far include a list extraction call, so this is
pretty widely useful, and it saves a few more keystrokes compared to the
old way.
As with the previous patch, back-patch the addition of these macros to
pg_list.h, so that the notation will be available when back-patching.
Patch by me, after an idea of Andrew Gierth's.
Discussion: https://postgr.es/m/14197.1491841216@sss.pgh.pa.us
src/include/nodes/pg_list.h | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/src/include/nodes/pg_list.h b/src/include/nodes/pg_list.h
index 16040f48dc1..67204b4c2e0 100644
--- a/src/include/nodes/pg_list.h
+++ b/src/include/nodes/pg_list.h
@@ -115,26 +115,32 @@ list_length(const List *l)
#define lfirst(lc) ((lc)->data.ptr_value)
#define lfirst_int(lc) ((lc)->data.int_value)
#define lfirst_oid(lc) ((lc)->data.oid_value)
+#define lfirst_node(type,lc) castNode(type, lfirst(lc))
#define linitial(l) lfirst(list_head(l))
#define linitial_int(l) lfirst_int(list_head(l))
#define linitial_oid(l) lfirst_oid(list_head(l))
+#define linitial_node(type,l) castNode(type, linitial(l))
#define lsecond(l) lfirst(lnext(list_head(l)))
#define lsecond_int(l) lfirst_int(lnext(list_head(l)))
#define lsecond_oid(l) lfirst_oid(lnext(list_head(l)))
+#define lsecond_node(type,l) castNode(type, lsecond(l))
#define lthird(l) lfirst(lnext(lnext(list_head(l))))
#define lthird_int(l) lfirst_int(lnext(lnext(list_head(l))))
#define lthird_oid(l) lfirst_oid(lnext(lnext(list_head(l))))
+#define lthird_node(type,l) castNode(type, lthird(l))
#define lfourth(l) lfirst(lnext(lnext(lnext(list_head(l)))))
#define lfourth_int(l) lfirst_int(lnext(lnext(lnext(list_head(l)))))
#define lfourth_oid(l) lfirst_oid(lnext(lnext(lnext(list_head(l)))))
+#define lfourth_node(type,l) castNode(type, lfourth(l))
#define llast(l) lfirst(list_tail(l))
#define llast_int(l) lfirst_int(list_tail(l))
#define llast_oid(l) lfirst_oid(list_tail(l))
+#define llast_node(type,l) castNode(type, llast(l))
/*
* Convenience macros for building fixed-length lists
@@ -209,6 +215,7 @@ extern List *list_truncate(List *list, int new_size);
extern void *list_nth(const List *list, int n);
extern int list_nth_int(const List *list, int n);
extern Oid list_nth_oid(const List *list, int n);
+#define list_nth_node(type,list,n) castNode(type, list_nth(list, n))
extern bool list_member(const List *list, const void *datum);
extern bool list_member_ptr(const List *list, const void *datum);
[parent: 649cd9085efb]