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Downgrade implicit casts to text to be assignment-only, except for the ones

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from the other string-category types; this eliminates a lot of surprising
interpretations that the parser could formerly make when there was no directly
applicable operator.

Create a general mechanism that supports casts to and from the standard string
types (text,varchar,bpchar) for *every* datatype, by invoking the datatype's
I/O functions.  These new casts are assignment-only in the to-string direction,
explicit-only in the other, and therefore should create no surprising behavior.
Remove a bunch of thereby-obsoleted datatype-specific casting functions.

The "general mechanism" is a new expression node type CoerceViaIO that can
actually convert between *any* two datatypes if their external text
representations are compatible.  This is more general than needed for the
immediate feature, but might be useful in plpgsql or other places in future.

This commit does nothing about the issue that applying the concatenation
operator || to non-text types will now fail, often with strange error messages
due to misinterpreting the operator as array concatenation.  Since it often
(not always) worked before, we should either make it succeed or at least give
a more user-friendly error; but details are still under debate.

Peter Eisentraut and Tom Lane
This commit is contained in:
Tom Lane
2007-06-05 21:31:09 +00:00
parent 1120b99445
commit 31edbadf4a
60 changed files with 850 additions and 1612 deletions
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85
contrib/isn/isn.c
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@ -7,7 +7,7 @@
* Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
*
* IDENTIFICATION
* $PostgreSQL: pgsql/contrib/isn/isn.c,v 1.5 2007/01/05 22:19:18 momjian Exp $
* $PostgreSQL: pgsql/contrib/isn/isn.c,v 1.6 2007/06/05 21:31:03 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -39,10 +39,6 @@ static const char *isn_names[] = {"EAN13/UPC/ISxN", "EAN13/UPC/ISxN", "EAN13", "
static bool g_weak = false;
static bool g_initialized = false;
/* Macros for converting TEXT to and from c-string */
#define GET_TEXT(cstrp) DatumGetTextP(DirectFunctionCall1(textin, CStringGetDatum(cstrp)))
#define GET_STR(textp) DatumGetCString(DirectFunctionCall1(textout, PointerGetDatum(textp)))
/***********************************************************************
**
@ -1042,30 +1038,6 @@ upc_in(PG_FUNCTION_ARGS)
/* casting functions
*/
PG_FUNCTION_INFO_V1(ean13_cast_to_text);
Datum
ean13_cast_to_text(PG_FUNCTION_ARGS)
{
ean13 val = PG_GETARG_EAN13(0);
char buf[MAXEAN13LEN + 1];
(void) ean2string(val, false, buf, false);
PG_RETURN_TEXT_P(GET_TEXT(buf));
}
PG_FUNCTION_INFO_V1(isn_cast_to_text);
Datum
isn_cast_to_text(PG_FUNCTION_ARGS)
{
ean13 val = PG_GETARG_EAN13(0);
char buf[MAXEAN13LEN + 1];
(void) ean2string(val, false, buf, true);
PG_RETURN_TEXT_P(GET_TEXT(buf));
}
PG_FUNCTION_INFO_V1(isbn_cast_from_ean13);
Datum
isbn_cast_from_ean13(PG_FUNCTION_ARGS)
@ -1115,61 +1087,6 @@ upc_cast_from_ean13(PG_FUNCTION_ARGS)
}
PG_FUNCTION_INFO_V1(ean13_cast_from_text);
Datum
ean13_cast_from_text(PG_FUNCTION_ARGS)
{
const char *str = GET_STR(PG_GETARG_TEXT_P(0));
ean13 result;
(void) string2ean(str, false, &result, EAN13);
PG_RETURN_EAN13(result);
}
PG_FUNCTION_INFO_V1(isbn_cast_from_text);
Datum
isbn_cast_from_text(PG_FUNCTION_ARGS)
{
const char *str = GET_STR(PG_GETARG_TEXT_P(0));
ean13 result;
(void) string2ean(str, false, &result, ISBN);
PG_RETURN_EAN13(result);
}
PG_FUNCTION_INFO_V1(ismn_cast_from_text);
Datum
ismn_cast_from_text(PG_FUNCTION_ARGS)
{
const char *str = GET_STR(PG_GETARG_TEXT_P(0));
ean13 result;
(void) string2ean(str, false, &result, ISMN);
PG_RETURN_EAN13(result);
}
PG_FUNCTION_INFO_V1(issn_cast_from_text);
Datum
issn_cast_from_text(PG_FUNCTION_ARGS)
{
const char *str = GET_STR(PG_GETARG_TEXT_P(0));
ean13 result;
(void) string2ean(str, false, &result, ISSN);
PG_RETURN_EAN13(result);
}
PG_FUNCTION_INFO_V1(upc_cast_from_text);
Datum
upc_cast_from_text(PG_FUNCTION_ARGS)
{
const char *str = GET_STR(PG_GETARG_TEXT_P(0));
ean13 result;
(void) string2ean(str, false, &result, UPC);
PG_RETURN_EAN13(result);
}
/* is_valid - returns false if the "invalid-check-digit-on-input" is set
*/
PG_FUNCTION_INFO_V1(is_valid);