PL/PGSQL: Dynamic Record Introspection - Mailing list pgsql-patches

From Titus von Boxberg
Subject PL/PGSQL: Dynamic Record Introspection
Date
Msg-id 42D5B297.7090804@bhi-hamburg.de
Whole thread Raw
Responses Re: PL/PGSQL: Dynamic Record Introspection
Re: PL/PGSQL: Dynamic Record Introspection
List pgsql-patches
Hi all,

I needed introspection capabilities for record types to write more generic
trigger procedures in PL/PGSQL.

With the following patch it's possible to
- extract all field names of a record into an array
- extract field count of a record
- address a single field of a record with a variable
   containing the field name (additional to the usual record.fieldname
   notation where the fieldname is hardcoded).

The syntax is
- record%NFIELDS gives the number of fields in the record
- record%FIELDNAMES gives the array of the field names
- record%scalarvariable extracts the field whose name
   is equal to the contents of scalarvariable

------------

The patch is nonintrusive in the sense that it only adds things
with one exception:
In function exec_eval_datum(), file pl_exec.c, line 3557 (after the patch)
I chose to convert the record field values to TEXT if the caller does
not require a certain type (expectedtypeid == InvalidOid).
Additionally, I cast the value from the record field type if
the destination Datum is of different type.

As far as I can see, this does no harm because in most cases
the expectedtypeid is correctly set. I just wanted to avoid that
if it is not set, the returned datum is of a more restrictive type
than TEXT.

------------

The patch is against a HEAD checkout from 07/12/05
The output comes from difforig.

Test code for the patch can be extracted from an example I put into
plpgsql.sgml

------------

Here is a summary of things that get patched by the file:
- add three new special parsing functions to pl_comp.c
   (plpgsql_parse_wordpercentword, plpgsql_parse_wordnfields,
   plpgsql_parse_wordfieldnames).
- modify PLpgSQL_recfield in plpgsql.h to either hold
   a conventional field name (record.fieldname) or a dno
   for the variable (record%variable).
- add two PLPGSQL_DTYPEs for the two new % notations
- modify "case PLPGSQL_DTYPE_RECFIELD:"
   in exec_eval_datum() and exec_assign_value()
   to deal with index strings from a variable
- add "case PLPGSQL_DTYPE_RECFIELDNAMES"
   and "case PLPGSQL_DTYPE_NRECFIELD"
   to exec_eval_datum() to evaluate  %FIELDNAMES
   and %NFIELDS expressions.
- update plpgsql.sgml in the docs directory

------------

Please notify me if I can be of further assistance.

Regards
Titus
*** ./doc/src/sgml/plpgsql.sgml.orig    Thu Jul 14 00:49:33 2005
--- ./doc/src/sgml/plpgsql.sgml    Thu Jul 14 01:15:41 2005
***************
*** 867,872 ****
--- 867,941 ----
     </para>

     <para>
+     To obtain the values of the fields the record is made up of,
+     the record variable can be qualified with the column or field
+     name. This can be done either literally with the usual dot notation
+     or the column name for indexing the record can be taken out of a scalar
+     variable. The syntax for this notation is Record_variable%IndexVariable.
+     To get information about the column fields, two special
+     notations exist that return all column names as an array (RecordVariable%FIELDNAMES)
+     and the count of fields stored in a record (RecordVariable%NFIELDS).
+     Thus, the RECORD can be viewed
+     as an associative array that allows for introspection of it's contents.
+     This feature is especially useful for writing generic triggers that
+     operate on records with unknown structure.
+     Here is an example that operates on the predefined record NEW in
+     a trigger procedure:
+ <programlisting>
+ CREATE OR REPLACE FUNCTION show_associative_records() RETURNS TRIGGER AS $ztt_u$
+     DECLARE
+         wmsg        TEXT;
+         column        TEXT;
+         colcontent    TEXT;
+         colnames    TEXT[];
+         coln        INT4;
+         coli        INT4;
+         testint8    INT8;
+     BEGIN
+ -- get the number of fields
+         coln := NEW%NFIELDS;
+         RAISE NOTICE 'Record type has % fields', coln;
+
+ -- obtain an array with all field names of the record
+         colnames := NEW%FIELDNAMES;
+         RAISE NOTICE 'All column names of test record: %', colnames;
+
+ -- show field names and contents of record
+         coli := 1;
+         LOOP
+             column := colnames[coli];
+             colcontent := NEW%column;
+             IF colcontent IS NULL
+             THEN
+                 colcontent := '<NULL>';
+             END IF;
+             RAISE NOTICE 'column name % of NEW: value %', column, colcontent;
+             coli := coli + 1;
+             EXIT WHEN coli > coln;
+         END LOOP;
+
+ -- get a single record field value indexed by the contents of the variable "column"
+ -- raises an error if the record does not have the field name from "column"
+         column := 'SomeFieldNameInYourRecord';
+ -- testint8 will contain NULL if the value of this column
+ -- has a different type and cannot be casted to int8!
+ -- use a TEXT scalar variable to avoid this problem.
+         testint8 := NEW%column;
+         RAISE WARNING 'Column name = %, Column content = %', column, testint8;
+
+ -- the "normal" way with fixed field name with dot notation:
+         wmsg := NEW.SomeFieldNameInYourRecord;
+         RAISE NOTICE 'Column content NEW.SomeFieldNameInYourRecord = %', wmsg;
+
+         RETURN NULL;
+     END;
+ $ztt_u$ LANGUAGE plpgsql;
+

+
+ </programlisting>
+    </para>
+
+    <para>
      Note that <literal>RECORD</> is not a true data type, only a placeholder.
      One should also realize that when a <application>PL/pgSQL</application>
      function is declared to return type <type>record</>, this is not quite the
*** ./src/pl/plpgsql/src/pl_comp.c.orig    Wed Jul 13 19:22:43 2005
--- ./src/pl/plpgsql/src/pl_comp.c    Thu Jul 14 00:25:42 2005
***************
*** 995,1001 ****

                  new = palloc(sizeof(PLpgSQL_recfield));
                  new->dtype = PLPGSQL_DTYPE_RECFIELD;
!                 new->fieldname = pstrdup(cp[1]);
                  new->recparentno = ns->itemno;

                  plpgsql_adddatum((PLpgSQL_datum *) new);
--- 995,1002 ----

                  new = palloc(sizeof(PLpgSQL_recfield));
                  new->dtype = PLPGSQL_DTYPE_RECFIELD;
!                 new->fieldindex.fieldname = strdup(cp[1]);
!                 new->fieldindex_flag = RECFIELD_USE_FIELDNAME;
                  new->recparentno = ns->itemno;

                  plpgsql_adddatum((PLpgSQL_datum *) new);
***************
*** 1101,1107 ****

                  new = palloc(sizeof(PLpgSQL_recfield));
                  new->dtype = PLPGSQL_DTYPE_RECFIELD;
!                 new->fieldname = pstrdup(cp[2]);
                  new->recparentno = ns->itemno;

                  plpgsql_adddatum((PLpgSQL_datum *) new);
--- 1102,1109 ----

                  new = palloc(sizeof(PLpgSQL_recfield));
                  new->dtype = PLPGSQL_DTYPE_RECFIELD;
!                 new->fieldindex.fieldname = strdup(cp[2]);
!                 new->fieldindex_flag = RECFIELD_USE_FIELDNAME;
                  new->recparentno = ns->itemno;

                  plpgsql_adddatum((PLpgSQL_datum *) new);
***************
*** 1551,1556 ****
--- 1553,1736 ----
      return T_DTYPE;
  }

+ /* ----------
+  * plpgsql_parse_wordpercentword
+  * lookup associative index into record
+  * ----------
+  */
+ int
+ plpgsql_parse_wordpercentword(char *word)
+ {
+     PLpgSQL_nsitem *ns1, *ns2;
+     char       *cp[2];
+     int        ret = T_ERROR;
+
+     /* convert % to . for plpgsql_convert_ident */
+     char * percl = strchr(word, '%');
+     if ( percl == NULL )
+         return T_ERROR;
+     *percl = '.';
+
+     /* Do case conversion and word separation */
+     plpgsql_convert_ident(word, cp, 2);
+     *percl = '%';
+
+     /*
+      * Lookup the first word
+      */
+     ns1 = plpgsql_ns_lookup(cp[0], NULL);
+     if ( ns1 == NULL )
+     {
+         pfree(cp[0]);
+         pfree(cp[1]);
+         return T_ERROR;
+     }
+
+     ns2 = plpgsql_ns_lookup(cp[1], NULL);
+     pfree(cp[0]);
+     pfree(cp[1]);
+     if ( ns2 == NULL )    /* name lookup failed */
+         return T_ERROR;
+
+     switch (ns1->itemtype)
+     {
+         case PLPGSQL_NSTYPE_REC:
+             {
+                 /*
+                  * First word is a record name, so second word must be an
+                  * variable holding the field name in this record.
+                  */
+                 if ( ns2->itemtype == PLPGSQL_NSTYPE_VAR ) {
+                     PLpgSQL_recfield *new;
+
+                     new = malloc(sizeof(PLpgSQL_recfield));
+                     new->dtype = PLPGSQL_DTYPE_RECFIELD;
+                     new->fieldindex.indexvar_no = ns2->itemno;
+                     new->fieldindex_flag = RECFIELD_USE_INDEX_VAR;
+                     new->recparentno = ns1->itemno;
+
+                     plpgsql_adddatum((PLpgSQL_datum *) new);
+
+                     plpgsql_yylval.scalar = (PLpgSQL_datum *) new;
+                     ret =  T_SCALAR;
+                 } /* IF VAR */
+                 break;
+             }
+         default:
+             break;
+     }
+     return ret;
+ } /* plpgsql_parse_wordpercentword */
+
+ /* ----------
+  * plpgsql_parse_wordnfields
+  * create # of fields in a record
+  * ----------
+  */
+ int
+ plpgsql_parse_wordnfields(char *word)
+ {
+     PLpgSQL_nsitem    *ns1;
+     char        *cp[2];
+     int        ret = T_ERROR;
+
+     /* convert % to . for plpgsql_convert_ident */
+     int        i = strlen(word) - 8;
+     Assert(word[i] == '%');
+     word[i] = '.';
+     /* Do case conversion and word separation */
+     plpgsql_convert_ident(word, cp, 2);
+     word[i] = '%';
+
+     /*
+      * Lookup the first word
+      */
+     ns1 = plpgsql_ns_lookup(cp[0], NULL);
+     if ( ns1 == NULL )
+     {
+         pfree(cp[0]);
+         pfree(cp[1]);
+         return T_ERROR;
+     }
+
+     pfree(cp[0]);
+     pfree(cp[1]);
+     switch (ns1->itemtype)
+     {
+         case PLPGSQL_NSTYPE_REC:
+             {
+                 PLpgSQL_recfieldproperties *new;
+
+                 new = malloc(sizeof(PLpgSQL_recfieldproperties));
+                 new->dtype = PLPGSQL_DTYPE_NRECFIELD;
+                 new->recparentno = ns1->itemno;
+                 plpgsql_adddatum((PLpgSQL_datum *) new);
+                 plpgsql_yylval.scalar = (PLpgSQL_datum *) new;
+                 ret =  T_SCALAR;    /* ??? */
+                 break;
+             }
+         default:
+             break;
+     }
+     return ret;
+ } /* plpgsql_parse_wordnfields */
+
+
+ /* ----------
+  * plpgsql_parse_wordfieldnames
+  * create fieldnames of a record
+  * ----------
+  */
+ int
+ plpgsql_parse_wordfieldnames(char *word)
+ {
+     PLpgSQL_nsitem    *ns1;
+     char        *cp[2];
+     int        ret = T_ERROR;
+
+     /* convert % to . for plpgsql_convert_ident */
+     int        i = strlen(word) - 11;
+     Assert(word[i] == '%');
+     word[i] = '.';
+     /* Do case conversion and word separation */
+     plpgsql_convert_ident(word, cp, 2);
+     word[i] = '%';
+
+     /*
+      * Lookup the first word
+      */
+     ns1 = plpgsql_ns_lookup(cp[0], NULL);
+     if ( ns1 == NULL )
+     {
+         pfree(cp[0]);
+         pfree(cp[1]);
+         return T_ERROR;
+     }
+
+     pfree(cp[0]);
+     pfree(cp[1]);
+
+     switch (ns1->itemtype)
+     {
+         case PLPGSQL_NSTYPE_REC:
+             {
+                 PLpgSQL_recfieldproperties *new;
+
+                 new = malloc(sizeof(PLpgSQL_recfieldproperties));
+                 new->dtype = PLPGSQL_DTYPE_RECFIELDNAMES;
+                 new->recparentno = ns1->itemno;
+                 plpgsql_adddatum((PLpgSQL_datum *) new);
+                 plpgsql_yylval.scalar = (PLpgSQL_datum *) new;
+                 ret =  T_SCALAR;    /* ??? */
+                 break;
+             }
+         default:
+             break;
+     }
+     return ret;
+ } /* plpgsql_parse_wordfieldnames */
+
+
  /*
   * plpgsql_build_variable - build a datum-array entry of a given
   * datatype
*** ./src/pl/plpgsql/src/pl_exec.c.orig    Wed Jul 13 19:22:08 2005
--- ./src/pl/plpgsql/src/pl_exec.c    Thu Jul 14 00:42:51 2005
***************
*** 716,721 ****
--- 716,723 ----
          case PLPGSQL_DTYPE_RECFIELD:
          case PLPGSQL_DTYPE_ARRAYELEM:
          case PLPGSQL_DTYPE_TRIGARG:
+         case PLPGSQL_DTYPE_NRECFIELD:
+         case PLPGSQL_DTYPE_RECFIELDNAMES:
              /*
               * These datum records are read-only at runtime, so no need
               * to copy them
***************
*** 825,830 ****
--- 827,834 ----

              case PLPGSQL_DTYPE_RECFIELD:
              case PLPGSQL_DTYPE_ARRAYELEM:
+             case PLPGSQL_DTYPE_NRECFIELD:
+             case PLPGSQL_DTYPE_RECFIELDNAMES:
                  break;

              default:
***************
*** 3154,3165 ****
                   * Get the number of the records field to change and the
                   * number of attributes in the tuple.
                   */
!                 fno = SPI_fnumber(rec->tupdesc, recfield->fieldname);
!                 if (fno == SPI_ERROR_NOATTRIBUTE)
                      ereport(ERROR,
!                             (errcode(ERRCODE_UNDEFINED_COLUMN),
!                              errmsg("record \"%s\" has no field \"%s\"",
!                                     rec->refname, recfield->fieldname)));
                  fno--;
                  natts = rec->tupdesc->natts;

--- 3158,3192 ----
                   * Get the number of the records field to change and the
                   * number of attributes in the tuple.
                   */
!                 if ( recfield->fieldindex_flag == RECFIELD_USE_FIELDNAME ) {
!                     fno = SPI_fnumber(rec->tupdesc, recfield->fieldindex.fieldname);
!                     if (fno == SPI_ERROR_NOATTRIBUTE)
!                         ereport(ERROR,
!                                 (errcode(ERRCODE_UNDEFINED_COLUMN),
!                                  errmsg("record \"%s\" has no field \"%s\"",
!                                         rec->refname, recfield->fieldindex.fieldname)));
!                 }
!                 else if ( recfield->fieldindex_flag == RECFIELD_USE_INDEX_VAR ) {
!                     PLpgSQL_var * idxvar = (PLpgSQL_var *) (estate->datums[recfield->fieldindex.indexvar_no]);
!                     char * fname = convert_value_to_string(idxvar->value, idxvar->datatype->typoid);
!                     if ( fname == NULL )
!                         ereport(ERROR,
!                                 (errcode(ERRCODE_UNDEFINED_COLUMN),
!                                 errmsg("record \"%s\": cannot evaluate variable to record index string",
!                                         rec->refname)));
!                     fno = SPI_fnumber(rec->tupdesc, fname);
!                     pfree(fname);
!                     if (fno == SPI_ERROR_NOATTRIBUTE)
!                         ereport(ERROR,
!                                 (errcode(ERRCODE_UNDEFINED_COLUMN),
!                                  errmsg("record \"%s\" has no field \"%s\"",
!                                         rec->refname, fname)));
!                 }
!                 else
                      ereport(ERROR,
!                         (errcode(ERRCODE_UNDEFINED_COLUMN),
!                         errmsg("record \"%s\": internal error",
!                                     rec->refname)));
                  fno--;
                  natts = rec->tupdesc->natts;

***************
*** 3497,3515 ****
                         errmsg("record \"%s\" is not assigned yet",
                                rec->refname),
                         errdetail("The tuple structure of a not-yet-assigned record is indeterminate.")));
!                 fno = SPI_fnumber(rec->tupdesc, recfield->fieldname);
!                 if (fno == SPI_ERROR_NOATTRIBUTE)
                      ereport(ERROR,
!                             (errcode(ERRCODE_UNDEFINED_COLUMN),
!                              errmsg("record \"%s\" has no field \"%s\"",
!                                     rec->refname, recfield->fieldname)));
!                 *typeid = SPI_gettypeid(rec->tupdesc, fno);
!                 *value = SPI_getbinval(rec->tup, rec->tupdesc, fno, isnull);
!                 if (expectedtypeid != InvalidOid && expectedtypeid != *typeid)
                      ereport(ERROR,
                              (errcode(ERRCODE_DATATYPE_MISMATCH),
!                              errmsg("type of \"%s.%s\" does not match that when preparing the plan",
!                                     rec->refname, recfield->fieldname)));
                  break;
              }

--- 3524,3670 ----
                         errmsg("record \"%s\" is not assigned yet",
                                rec->refname),
                         errdetail("The tuple structure of a not-yet-assigned record is indeterminate.")));
!                 if ( recfield->fieldindex_flag == RECFIELD_USE_FIELDNAME ) {
!                     fno = SPI_fnumber(rec->tupdesc, recfield->fieldindex.fieldname);
!                     if (fno == SPI_ERROR_NOATTRIBUTE)
!                         ereport(ERROR,
!                                 (errcode(ERRCODE_UNDEFINED_COLUMN),
!                                  errmsg("record \"%s\" has no field \"%s\"",
!                                         rec->refname, recfield->fieldindex.fieldname)));
!                 }
!                 else if ( recfield->fieldindex_flag == RECFIELD_USE_INDEX_VAR ) {
!                     PLpgSQL_var * idxvar = (PLpgSQL_var *) (estate->datums[recfield->fieldindex.indexvar_no]);
!                     char * fname = convert_value_to_string(idxvar->value, idxvar->datatype->typoid);
!                     if ( fname == NULL )
!                         ereport(ERROR,
!                                 (errcode(ERRCODE_UNDEFINED_COLUMN),
!                                 errmsg("record \"%s\": cannot evaluate variable to record index string",
!                                         rec->refname)));
!                     fno = SPI_fnumber(rec->tupdesc, fname);
!                     pfree(fname);
!                     if (fno == SPI_ERROR_NOATTRIBUTE)
!                         ereport(ERROR,
!                                 (errcode(ERRCODE_UNDEFINED_COLUMN),
!                                  errmsg("record \"%s\" has no field \"%s\"",
!                                         rec->refname, fname)));
!                 }
!                 else
                      ereport(ERROR,
!                         (errcode(ERRCODE_UNDEFINED_COLUMN),
!                         errmsg("record \"%s\": internal error",
!                                 rec->refname)));
!
!                 /* Do not allow typeids to become "narrowed" by InvalidOids
!                 causing specialized typeids from the tuple restricting the destination */
!                 if ( expectedtypeid == InvalidOid )
!                     expectedtypeid = TEXTOID;    /* TEXT should be able to cope with anything */
!                 /* Want to be able store the value in any compatible variable */
!                 if ( expectedtypeid != SPI_gettypeid(rec->tupdesc, fno) ) {
!                     Datum cval = SPI_getbinval(rec->tup, rec->tupdesc, fno, isnull);
!                     /* elog(WARNING, "casting record field value to expected value!"); */
!                     cval =   exec_simple_cast_value(cval,
!                                     SPI_gettypeid(rec->tupdesc, fno),
!                                     expectedtypeid,
!                                     -1,
!                                     isnull);
!
!                     *value = cval;
!                     *typeid = expectedtypeid;
!                     /* ereport(ERROR,
!                             (errcode(ERRCODE_DATATYPE_MISMATCH),
!                              errmsg("type of \"%s\" does not match that when preparing the plan",
!                                     rec->refname)));
!                     */
!                 } /* IF expected typeid is valid but does not match! */
!                 else { /* expected typeid matches */
!                     *value = SPI_getbinval(rec->tup, rec->tupdesc, fno, isnull);
!                     *typeid = SPI_gettypeid(rec->tupdesc, fno);
!                 } /* ELSE */
!                 break;
!             }
!
!         case PLPGSQL_DTYPE_RECFIELDNAMES:
!             /* Construct array datum from record field names */
!             {
!                 Oid            arraytypeid,
!                             arrayelemtypeid = TEXTOID;
!                 int16            arraytyplen,
!                             elemtyplen;
!                 bool            elemtypbyval;
!                 char            elemtypalign;
!                 ArrayType        *arrayval;
!
!                 PLpgSQL_rec        *rec = (PLpgSQL_rec *) (estate->datums[((PLpgSQL_recfieldproperties *)
datum)->recparentno]);
!                 int            fc, tfc = 0;
!                 Datum            *arrayelems;
!                 char            *fieldname;
!
!                 if (!HeapTupleIsValid(rec->tup))
!                     ereport(ERROR,
!                       (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
!                        errmsg("record \"%s\" is not assigned yet",
!                               rec->refname),
!                        errdetail("The tuple structure of a not-yet-assigned record is indeterminate.")));
!                 arrayelems = palloc(sizeof(Datum) * rec->tupdesc->natts);
!                 arraytypeid = get_array_type(arrayelemtypeid);
!                 arraytyplen = get_typlen(arraytypeid);
!                 get_typlenbyvalalign(arrayelemtypeid,
!                              &elemtyplen,
!                              &elemtypbyval,
!                              &elemtypalign);
!
!                 if ( expectedtypeid != InvalidOid && expectedtypeid != arraytypeid )
!                     ereport(ERROR,
!                             (errcode(ERRCODE_DATATYPE_MISMATCH),
!                              errmsg("type of \"%s\" does not match array type when preparing the plan",
!                                     rec->refname)));
!                 for ( fc = 0; fc < rec->tupdesc->natts; ++fc ) {
!                     fieldname = SPI_fname(rec->tupdesc, fc+1);
!                     if ( fieldname ) {
!                         arrayelems[fc] = DirectFunctionCall1(textin, CStringGetDatum(fieldname));
!                         pfree(fieldname);
!                         ++tfc;
!                     } /* IF */
!                 } /* FOR */
!
!                 arrayval = construct_array(arrayelems, tfc,
!                              arrayelemtypeid,
!                              elemtyplen,
!                              elemtypbyval,
!                              elemtypalign);
!
!
!                 /* construct_array copies data; free temp elem array */
! #if    0
!                 for ( fc = 0; fc < tfc; ++fc )
!                     pfree(DatumGetPointer(arrayelems[fc]);
!                 pfree(arrayelems);
! #endif
!                 *value = PointerGetDatum(arrayval);
!                 *typeid = arraytypeid;
!                 *isnull = false;
!                 break;
!             }
!
!         case PLPGSQL_DTYPE_NRECFIELD:
!             /* Get # of fields in a record */
!             {
!                 PLpgSQL_rec        *rec = (PLpgSQL_rec *) (estate->datums[((PLpgSQL_recfieldproperties *)
datum)->recparentno]);
!
!                 if (!HeapTupleIsValid(rec->tup))
!                     ereport(ERROR,
!                       (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
!                        errmsg("record \"%s\" is not assigned yet",
!                               rec->refname),
!                        errdetail("The tuple structure of a not-yet-assigned record is indeterminate.")));
!                 if ( expectedtypeid != InvalidOid && expectedtypeid != INT4OID )
                      ereport(ERROR,
                              (errcode(ERRCODE_DATATYPE_MISMATCH),
!                              errmsg("type of \"%s\" does not match scalar type",
!                                     rec->refname)));
!                 *value = Int32GetDatum(rec->tupdesc->natts);
!                 *typeid = INT4OID;
!                 *isnull = false;
                  break;
              }

*** ./src/pl/plpgsql/src/pl_funcs.c.orig    Wed Jul 13 19:23:08 2005
--- ./src/pl/plpgsql/src/pl_funcs.c    Wed Jul 13 19:32:17 2005
***************
*** 1066,1074 ****
                  printf("REC %s\n", ((PLpgSQL_rec *) d)->refname);
                  break;
              case PLPGSQL_DTYPE_RECFIELD:
!                 printf("RECFIELD %-16s of REC %d\n",
!                        ((PLpgSQL_recfield *) d)->fieldname,
!                        ((PLpgSQL_recfield *) d)->recparentno);
                  break;
              case PLPGSQL_DTYPE_ARRAYELEM:
                  printf("ARRAYELEM of VAR %d subscript ",
--- 1066,1078 ----
                  printf("REC %s\n", ((PLpgSQL_rec *) d)->refname);
                  break;
              case PLPGSQL_DTYPE_RECFIELD:
!                 if ( ((PLpgSQL_recfield *) d)->fieldindex_flag == RECFIELD_USE_FIELDNAME )
!                     printf("RECFIELD %-16s of REC %d\n",
!                            ((PLpgSQL_recfield *) d)->fieldindex.fieldname,
!                            ((PLpgSQL_recfield *) d)->recparentno);
!                 else
!                     printf("RECFIELD Variable of REC %d\n",
!                            ((PLpgSQL_recfield *) d)->recparentno);
                  break;
              case PLPGSQL_DTYPE_ARRAYELEM:
                  printf("ARRAYELEM of VAR %d subscript ",
*** ./src/pl/plpgsql/src/plpgsql.h.orig    Wed Jul 13 19:21:32 2005
--- ./src/pl/plpgsql/src/plpgsql.h    Wed Jul 13 19:19:30 2005
***************
*** 73,79 ****
      PLPGSQL_DTYPE_RECFIELD,
      PLPGSQL_DTYPE_ARRAYELEM,
      PLPGSQL_DTYPE_EXPR,
!     PLPGSQL_DTYPE_TRIGARG
  };

  /* ----------
--- 73,81 ----
      PLPGSQL_DTYPE_RECFIELD,
      PLPGSQL_DTYPE_ARRAYELEM,
      PLPGSQL_DTYPE_EXPR,
!     PLPGSQL_DTYPE_TRIGARG,
!     PLPGSQL_DTYPE_RECFIELDNAMES,
!     PLPGSQL_DTYPE_NRECFIELD
  };

  /* ----------
***************
*** 269,278 ****
  {                                /* Field in record */
      int            dtype;
      int            rfno;
!     char       *fieldname;
      int            recparentno;    /* dno of parent record */
  } PLpgSQL_recfield;


  typedef struct
  {                                /* Element of array variable */
--- 271,294 ----
  {                                /* Field in record */
      int            dtype;
      int            rfno;
!     union {
!         char    *fieldname;
!         int    indexvar_no;        /* dno of variable holding index string */
!     } fieldindex;
!     enum {
!         RECFIELD_USE_FIELDNAME,
!         RECFIELD_USE_INDEX_VAR,
!     }    fieldindex_flag;
      int            recparentno;    /* dno of parent record */
  } PLpgSQL_recfield;

+ typedef struct
+ {                                /* Field in record */
+     int            dtype;
+     int            rfno;
+     int            recparentno;            /* dno of parent record */
+ } PLpgSQL_recfieldproperties;
+

  typedef struct
  {                                /* Element of array variable */
***************
*** 678,683 ****
--- 694,702 ----
  extern int    plpgsql_parse_tripwordtype(char *word);
  extern int    plpgsql_parse_wordrowtype(char *word);
  extern int    plpgsql_parse_dblwordrowtype(char *word);
+ extern int    plpgsql_parse_wordnfields(char *word);
+ extern int    plpgsql_parse_wordfieldnames(char *word);
+ extern int    plpgsql_parse_wordpercentword(char *word);
  extern PLpgSQL_type *plpgsql_parse_datatype(const char *string);
  extern PLpgSQL_type *plpgsql_build_datatype(Oid typeOid, int32 typmod);
  extern PLpgSQL_variable *plpgsql_build_variable(const char *refname, int lineno,
*** ./src/pl/plpgsql/src/scan.l.orig    Wed Jul 13 19:21:59 2005
--- ./src/pl/plpgsql/src/scan.l    Wed Jul 13 19:33:30 2005
***************
*** 243,248 ****
--- 243,257 ----
  {param}{space}*\.{space}*{identifier}{space}*%ROWTYPE    {
      plpgsql_error_lineno = plpgsql_scanner_lineno();
      return plpgsql_parse_dblwordrowtype(yytext); }
+ {identifier}{space}*%NFIELDS        {
+     plpgsql_error_lineno = plpgsql_scanner_lineno();
+     return plpgsql_parse_wordnfields(yytext); }
+ {identifier}{space}*%FIELDNAMES        {
+     plpgsql_error_lineno = plpgsql_scanner_lineno();
+     return plpgsql_parse_wordfieldnames(yytext); }
+ {identifier}{space}*%{identifier}        {
+     plpgsql_error_lineno = plpgsql_scanner_lineno();
+     return plpgsql_parse_wordpercentword(yytext); }

  {digit}+        { return T_NUMBER;            }


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