/*
- * Location tracking support --- simpler than bison's default, since we only
- * want to track the start position not the end position of each nonterminal.
+ * Location tracking support. Unlike bison's default, we only want
+ * to track the start position not the end position of each nonterminal.
+ * Nonterminals that reduce to empty receive position "-1". Since a
+ * production's leading RHS nonterminal(s) may have reduced to empty,
+ * we have to scan to find the first one that's not -1.
*/
#define YYLLOC_DEFAULT(Current, Rhs, N) \
do { \
- if ((N) > 0) \
- (Current) = (Rhs)[1]; \
- else \
- (Current) = (-1); \
+ (Current) = (-1); \
+ for (int _i = 1; _i <= (N); _i++) \
+ { \
+ if ((Rhs)[_i] >= 0) \
+ { \
+ (Current) = (Rhs)[_i]; \
+ break; \
+ } \
+ } \
} while (0)
-/*
- * The above macro assigns -1 (unknown) as the parse location of any
- * nonterminal that was reduced from an empty rule, or whose leftmost
- * component was reduced from an empty rule. This is problematic
- * for nonterminals defined like
- * OptFooList: / * EMPTY * / { ... } | OptFooList Foo { ... } ;
- * because we'll set -1 as the location during the first reduction and then
- * copy it during each subsequent reduction, leaving us with -1 for the
- * location even when the list is not empty. To fix that, do this in the
- * action for the nonempty rule(s):
- * if (@$ < 0) @$ = @2;
- * (Although we have many nonterminals that follow this pattern, we only
- * bother with fixing @$ like this when the nonterminal's parse location
- * is actually referenced in some rule.)
- *
- * A cleaner answer would be to make YYLLOC_DEFAULT scan all the Rhs
- * locations until it's found one that's not -1. Then we'd get a correct
- * location for any nonterminal that isn't entirely empty. But this way
- * would add overhead to every rule reduction, and so far there's not been
- * a compelling reason to pay that overhead.
- */
-
/*
* Bison doesn't allocate anything that needs to live across parser calls,
* so we can easily have it use palloc instead of malloc. This prevents
| MODE_PLPGSQL_EXPR PLpgSQL_Expr
{
pg_yyget_extra(yyscanner)->parsetree =
- list_make1(makeRawStmt($2, 0));
+ list_make1(makeRawStmt($2, @2));
}
| MODE_PLPGSQL_ASSIGN1 PLAssignStmt
{
n->nnames = 1;
pg_yyget_extra(yyscanner)->parsetree =
- list_make1(makeRawStmt((Node *) n, 0));
+ list_make1(makeRawStmt((Node *) n, @2));
}
| MODE_PLPGSQL_ASSIGN2 PLAssignStmt
{
n->nnames = 2;
pg_yyget_extra(yyscanner)->parsetree =
- list_make1(makeRawStmt((Node *) n, 0));
+ list_make1(makeRawStmt((Node *) n, @2));
}
| MODE_PLPGSQL_ASSIGN3 PLAssignStmt
{
n->nnames = 3;
pg_yyget_extra(yyscanner)->parsetree =
- list_make1(makeRawStmt((Node *) n, 0));
+ list_make1(makeRawStmt((Node *) n, @2));
}
;
/*
* At top level, we wrap each stmt with a RawStmt node carrying start location
- * and length of the stmt's text. Notice that the start loc/len are driven
- * entirely from semicolon locations (@2). It would seem natural to use
- * @1 or @3 to get the true start location of a stmt, but that doesn't work
- * for statements that can start with empty nonterminals (opt_with_clause is
- * the main offender here); as noted in the comments for YYLLOC_DEFAULT,
- * we'd get -1 for the location in such cases.
- * We also take care to discard empty statements entirely.
+ * and length of the stmt's text.
+ * We also take care to discard empty statements entirely (which among other
+ * things dodges the problem of assigning them a location).
*/
stmtmulti: stmtmulti ';' toplevel_stmt
{
updateRawStmtEnd(llast_node(RawStmt, $1), @2);
}
if ($3 != NULL)
- $$ = lappend($1, makeRawStmt($3, @2 + 1));
+ $$ = lappend($1, makeRawStmt($3, @3));
else
$$ = $1;
}
| toplevel_stmt
{
if ($1 != NULL)
- $$ = list_make1(makeRawStmt($1, 0));
+ $$ = list_make1(makeRawStmt($1, @1));
else
$$ = NIL;
}
OptSchemaEltList:
OptSchemaEltList schema_stmt
{
- if (@$ < 0) /* see comments for YYLLOC_DEFAULT */
- @$ = @2;
$$ = lappend($1, $2);
}
| /* EMPTY */
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