database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-07-18 17:42:25 +03:00
Code Activity

Represent BETWEEN as a special node type in raw parse trees.

Browse Source 
Previously, gram.y itself converted BETWEEN into AND (or AND/OR) nests of
expression comparisons.  This was always as bogus as could be, but fixing
it hasn't risen to the top of the to-do list.  The present patch invents an
A_Expr representation for BETWEEN expressions, and does the expansion to
comparison trees in parse_expr.c which is at least a slightly saner place
to be doing semantic conversions.  There should be no change in the post-
parse-analysis results.

This does nothing for the semantic issues with BETWEEN (dubious connection
to btree-opclass semantics, and multiple evaluation of possibly volatile
subexpressions) ... but it's a necessary preliminary step before we could
fix any of that.  The main immediate benefit is that preserving BETWEEN as
an identifiable raw-parse-tree construct will enable better error messages.

While at it, fix the code so that multiply-referenced subexpressions are
physically duplicated before being passed through transformExpr().  This
gets rid of one of the principal reasons why transformExpr() has
historically had to allow already-processed input.
This commit is contained in:
Tom Lane
2015-02-22 13:57:56 -05:00
parent 74811c4050
commit 34af082f95
4 changed files with 144 additions and 36 deletions
Download Patch File Download Diff File Expand all files Collapse all files

16
src/backend/nodes/outfuncs.c
View File

@ -2512,6 +2512,22 @@ _outAExpr(StringInfo str, const A_Expr *node)
appendStringInfoString(str, " IN ");
WRITE_NODE_FIELD(name);
break;
case AEXPR_BETWEEN:
appendStringInfoString(str, " BETWEEN ");
WRITE_NODE_FIELD(name);
break;
case AEXPR_NOT_BETWEEN:
appendStringInfoString(str, " NOT_BETWEEN ");
WRITE_NODE_FIELD(name);
break;
case AEXPR_BETWEEN_SYM:
appendStringInfoString(str, " BETWEEN_SYM ");
WRITE_NODE_FIELD(name);
break;
case AEXPR_NOT_BETWEEN_SYM:
appendStringInfoString(str, " NOT_BETWEEN_SYM ");
WRITE_NODE_FIELD(name);
break;
default:
appendStringInfoString(str, " ??");
break;