diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 9b7e967..b2d2ed6 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -1519,21 +1519,13 @@
format
format(formatstr text
- [, str "any" [, ...] ])
+ [, formatarg "any" [, ...] ])
text
Format arguments according to a format string.
- This function is similar to the C function
- sprintf, but only the following conversion specifications
- are recognized: %s interpolates the corresponding
- argument as a string; %I escapes its argument as
- an SQL identifier; %L escapes its argument as an
- SQL literal; %% outputs a literal %.
- A conversion can reference an explicit parameter position by preceding
- the conversion specifier with n$, where
- n is the argument position.
- See also .
+ This function is similar to the C function sprintf.
+ See .
format('Hello %s, %1$s', 'World')
Hello World, World
@@ -2847,6 +2839,186 @@
+
+ <function>format</function>
+
+
+ format
+
+
+
+ The function format produces formatted output according to
+ a format string in a similar way to the C function sprintf.
+
+
+
+
+format(formatstr text [, formatarg "any" [, ...] ])
+
+ formatstr is a format string that specifies how the
+ result should be formatted. Text in the format string is copied directly
+ to the result, except where format specifiers are used.
+ Format specifiers act as placeholders in the string, allowing subsequent
+ function arguments to be formatted and inserted into the result.
+
+
+
+ Format specifiers are introduced by a % character and take
+ the form
+
+%[parameter][flags][width]type
+
+
+
+ parameter (optional)
+
+
+ An expression of the form n$ where
+ n is the index of the argument to use for the format
+ specifier's value. An index of 1 means the first argument after
+ formatstr. If the parameter field is
+ omitted, the default is to use the next argument.
+
+
+SELECT format('Testing %s, %s, %s', 'one', 'two', 'three');
+Result: Testing one, two, three
+
+SELECT format('Testing %3$s, %2$s, %1$s', 'one', 'two', 'three');
+Result: Testing three, two, one
+
+
+
+ Note that unlike the C function sprintf defined in the
+ Single UNIX Specification, the format function in
+ PostgreSQL allows format specifiers with and without
+ explicit parameter fields to be mixed in the same
+ format string. A format specifier without a
+ parameter field always uses the next argument after
+ the last argument consumed. In addition, the
+ PostgreSQL format function does not
+ require all function arguments to be referred to in the format
+ string.
+
+
+SELECT format('Testing %3$s, %2$s, %s', 'one', 'two', 'three');
+Result: Testing three, two, three
+
+
+
+
+
+ flags (optional)
+
+
+ Additional options controlling how the format specifier's output is
+ formatted. Currently the only supported flag is an minus sign
+ (-) which will cause the format specifier's output to be
+ left-aligned. This has no effect unless the width
+ field is also specified.
+
+
+SELECT format('|%10s|%-10s|', 'foo', 'bar');
+Result: | foo|bar |
+
+
+
+
+
+ width (optional)
+
+
+ Specifies the minimum number of characters to use to
+ display the format specifier's output. The width may be specified
+ using any of the following: a positive integer; an asterisk
+ (*) to use the next function argument as the width; or an
+ expression of the form *n$ to use the
+ nth function argument as the width.
+
+
+
+ If the width comes from a function argument, that argument is
+ consumed before the argument that is used for the format
+ specifier's value. If the width argument is negative, the result is
+ left aligned, as if the - flag had been specified.
+
+
+SELECT format('|%10s|', 'foo');
+Result: | foo|
+
+SELECT format('|%*s|', 10, 'foo');
+Result: | foo|
+
+SELECT format('|%*s|', -10, 'foo');
+Result: |foo |
+
+SELECT format('|%-*s|', 10, 'foo');
+Result: |foo |
+
+SELECT format('|%-*s|', -10, 'foo');
+Result: |foo |
+
+SELECT format('|%*2$s|', 'foo', 10, 'bar');
+Result: | bar|
+
+SELECT format('|%3$*2$s|', 'foo', 10, 'bar');
+Result: | bar|
+
+
+
+
+
+ type (required)
+
+
+ The type of format conversion to use to produce the format
+ specifier's output. The following types are supported:
+
+
+
+ s formats the argument value as a simple
+ string. A null value is treated as an empty string.
+
+
+
+
+ I escapes the value as an SQL identifier. It
+ is an error for the value to be null.
+
+
+
+
+ L escapes the value as an SQL literal. A null
+ value is displayed as the literal value NULL.
+
+
+
+
+
+SELECT format('Hello %s', 'World');
+Result: Hello World
+
+SELECT format('DROP TABLE %I', 'Foo bar');
+Result: DROP TABLE "Foo bar"
+
+SELECT format('SELECT %L', E'O\'Reilly');
+Result: SELECT 'O''Reilly'
+
+
+
+ The %I and %L format specifiers may be used
+ to safely construct dynamic SQL statements. See
+ .
+
+
+
+
+
+
+
+ In addition to the format specifiers above, the special escape sequence
+ %% may be used to output a literal % character.
+
+
diff --git a/src/backend/utils/adt/varlena.c b/src/backend/utils/adt/varlena.c
index e69b7dd..19b8049 100644
--- a/src/backend/utils/adt/varlena.c
+++ b/src/backend/utils/adt/varlena.c
@@ -78,7 +78,8 @@ static bytea *bytea_overlay(bytea *t1, bytea *t2, int sp, int sl);
static StringInfo makeStringAggState(FunctionCallInfo fcinfo);
static void text_format_string_conversion(StringInfo buf, char conversion,
FmgrInfo *typOutputInfo,
- Datum value, bool isNull);
+ Datum value, bool isNull,
+ int flags, int width);
static Datum text_to_array_internal(PG_FUNCTION_ARGS);
static text *array_to_text_internal(FunctionCallInfo fcinfo, ArrayType *v,
const char *fldsep, const char *null_string);
@@ -3996,6 +3997,135 @@ text_reverse(PG_FUNCTION_ARGS)
PG_RETURN_TEXT_P(result);
}
+#define FORWARD_PARSE_POINT(ptr) \
+do { \
+ if (++(ptr) >= (end_ptr)) \
+ ereport(ERROR, \
+ (errcode(ERRCODE_INVALID_PARAMETER_VALUE), \
+ errmsg("unterminated conversion specifier"))); \
+} while (0)
+
+/*
+ * Parse congiguous digits into decimal number.
+ *
+ * Returns true if some digits could be parsed and *ptr moved to the next
+ * character to be parsed. The value is returned into *value.
+ */
+static bool
+text_format_parse_digits(const char **ptr, const char *end_ptr, int *value)
+{
+ const char *cp = *ptr;
+ int wval = 0;
+ bool found;
+
+ /*
+ * continue, only when start_ptr is less than end_ptr.
+ * Overrun of cp is checked in FORWARD_PARSE_POINT.
+ */
+ while (*cp >= '0' && *cp <= '9')
+ {
+ int newnum = wval * 10 + (*cp - '0');
+
+ if (newnum / 10 != wval) /* overflow? */
+ ereport(ERROR,
+ (errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
+ errmsg("number is out of range")));
+ wval = newnum;
+ FORWARD_PARSE_POINT(cp);
+ }
+
+ found = (cp > *ptr);
+ *value = wval;
+ *ptr = cp;
+
+ return found;
+}
+
+#define TEXT_FORMAT_FLAG_MINUS 0x0001 /* is minus in format string? */
+
+/*
+ * parse format specification
+ * [argpos][flags][width]type
+ *
+ * Return values are,
+ * static const char * : Address to be parsed next.
+ * valarg : argument position for value to be printed. -1 means missing.
+ * widtharg : argument position for width. Zero means that argument position
+ * is not specified and -1 means missing.
+ * flags : flags
+ * width : the value for direct width specification, zero means that width
+ * is not specified.
+ */
+static const char *
+text_format_parse_format(const char *start_ptr, const char *end_ptr,
+ int *valarg, int *widtharg, int *flags, int *width)
+{
+ const char *cp = start_ptr;
+ int n;
+
+ /* set defaults to out parameters */
+ *valarg = -1;
+ *widtharg = -1;
+ *flags = 0;
+ *width = 0;
+
+ /* try to identify first number */
+ if (text_format_parse_digits(&cp, end_ptr, &n))
+ {
+ if (*cp != '$')
+ {
+ *width = n; /* The number should be width */
+ return cp;
+ }
+ /* Explicit 0 for argument index is immediately refused */
+ if (n == 0)
+ ereport(ERROR,
+ (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+ errmsg("conversion specifies argument 0, but arguments are numbered from 1")));
+ *valarg = n; /* The number was argument position */
+ FORWARD_PARSE_POINT(cp);
+ }
+
+ /* Check for flags, only minus is supported now. */
+ while (*cp == '-')
+ {
+ *flags = *flags | TEXT_FORMAT_FLAG_MINUS;
+ FORWARD_PARSE_POINT(cp);
+ }
+
+ /* try to parse indirect width */
+ if (*cp == '*')
+ {
+ FORWARD_PARSE_POINT(cp);
+
+ if (text_format_parse_digits(&cp, end_ptr, &n)){
+ /* number in this position should be closed by $ */
+ if (*cp != '$')
+ ereport(ERROR,
+ (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+ errmsg("unexpected char \"%c\".",*cp)));
+ FORWARD_PARSE_POINT(cp);
+
+ /* Explicit 0 for argument index is immediately refused */
+ if (n == 0)
+ ereport(ERROR,
+ (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+ errmsg("conversion specifies argument 0, but arguments are numbered from 1")));
+ *widtharg = n;
+ }
+ else
+ *widtharg = 0; /* 0 means argument position is not specified */
+
+ return cp;
+ }
+
+ /* last possible number - width */
+ if (text_format_parse_digits(&cp, end_ptr, &n))
+ *width = n;
+
+ return cp;
+}
+
/*
* Returns a formated string
*/
@@ -4016,6 +4146,8 @@ text_format(PG_FUNCTION_ARGS)
Oid element_type = InvalidOid;
Oid prev_type = InvalidOid;
FmgrInfo typoutputfinfo;
+ FmgrInfo typoutputinfo_width;
+ Oid prev_type_width = InvalidOid;
/* When format string is null, returns null */
if (PG_ARGISNULL(0))
@@ -4077,7 +4209,7 @@ text_format(PG_FUNCTION_ARGS)
}
/* Setup for main loop. */
- fmt = PG_GETARG_TEXT_PP(0);
+ fmt = PG_GETARG_TEXT_PP(arg++);
start_ptr = VARDATA_ANY(fmt);
end_ptr = start_ptr + VARSIZE_ANY_EXHDR(fmt);
initStringInfo(&str);
@@ -4088,6 +4220,10 @@ text_format(PG_FUNCTION_ARGS)
Datum value;
bool isNull;
Oid typid;
+ int valarg;
+ int widtharg;
+ int flags;
+ int width;
/*
* If it's not the start of a conversion specifier, just copy it to
@@ -4099,11 +4235,7 @@ text_format(PG_FUNCTION_ARGS)
continue;
}
- /* Did we run off the end of the string? */
- if (++cp >= end_ptr)
- ereport(ERROR,
- (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
- errmsg("unterminated conversion specifier")));
+ FORWARD_PARSE_POINT(cp);
/* Easy case: %% outputs a single % */
if (*cp == '%')
@@ -4112,69 +4244,84 @@ text_format(PG_FUNCTION_ARGS)
continue;
}
- /*
- * If the user hasn't specified an argument position, we just advance
- * to the next one. If they have, we must parse it.
- */
- if (*cp < '0' || *cp > '9')
+ cp = text_format_parse_format(cp, end_ptr,
+ &valarg, &widtharg, &flags, &width);
+
+ if (widtharg >= 0)
{
- ++arg;
- if (arg <= 0) /* overflow? */
- {
- /*
- * Should not happen, as you can't pass billions of arguments
- * to a function, but better safe than sorry.
- */
+ if (widtharg > 0)
+ /* be consistent, move ordered argument together with
+ * positional */
+ arg = widtharg;
+
+ if (arg >= nargs)
ereport(ERROR,
- (errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
- errmsg("argument number is out of range")));
- }
- }
- else
- {
- bool unterminated = false;
+ (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+ errmsg("too few arguments for format")));
- /* Parse digit string. */
- arg = 0;
- do
+ if (!funcvariadic)
{
- int newarg = arg * 10 + (*cp - '0');
+ value = PG_GETARG_DATUM(arg);
+ isNull = PG_ARGISNULL(arg);
+ typid = get_fn_expr_argtype(fcinfo->flinfo, arg);
+ }
+ else
+ {
+ value = elements[arg - 1];
+ isNull = nulls[arg - 1];
+ typid = element_type;
+ }
+ if (!OidIsValid(typid))
+ elog(ERROR, "could not determine data type of format() input");
- if (newarg / 10 != arg) /* overflow? */
- ereport(ERROR,
- (errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
- errmsg("argument number is out of range")));
- arg = newarg;
- ++cp;
- } while (cp < end_ptr && *cp >= '0' && *cp <= '9');
+ arg++;
/*
- * If we ran off the end, or if there's not a $ next, or if the $
- * is the last character, the conversion specifier is improperly
- * terminated.
+ * we don't need to different between NULL and zero in this moment,
+ * NULL means ignore this width - same as zero.
*/
- if (cp == end_ptr || *cp != '$')
- unterminated = true;
+ if (isNull)
+ width = 0;
+ else if (typid == INT4OID)
+ width = DatumGetInt32(value);
+ else if (typid == INT2OID)
+ width = DatumGetInt16(value);
else
{
- ++cp;
- if (cp == end_ptr)
- unterminated = true;
- }
- if (unterminated)
- ereport(ERROR,
- (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
- errmsg("unterminated conversion specifier")));
+ char *str;
- /* There's no argument 0. */
- if (arg == 0)
- ereport(ERROR,
- (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
- errmsg("conversion specifies argument 0, but arguments are numbered from 1")));
+ /* simple IO cast to int */
+ if (typid != prev_type_width)
+ {
+ Oid typoutputfunc;
+ bool typIsVarlena;
+
+ getTypeOutputInfo(typid, &typoutputfunc, &typIsVarlena);
+ fmgr_info(typoutputfunc, &typoutputinfo_width);
+ prev_type_width = typid;
+ }
+
+ /* Stringify. */
+ str = OutputFunctionCall(&typoutputinfo_width, value);
+
+ /* get int value */
+ width = pg_atoi(str, sizeof(int32), '\0');
+ pfree(str);
+ }
}
- /* Not enough arguments? Deduct 1 to avoid counting format string. */
- if (arg > nargs - 1)
+ /* We calculate -width later but -INT_MIN is undefined for int. */
+ if (width <= INT_MIN)
+ ereport(ERROR,
+ (errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
+ errmsg("number is out of range")));
+
+ if (valarg >= 0)
+ /* be consistent, move ordered argument together with
+ * positional */
+ arg = valarg;
+
+ if (arg >= nargs)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("too few arguments for format")));
@@ -4195,6 +4342,8 @@ text_format(PG_FUNCTION_ARGS)
if (!OidIsValid(typid))
elog(ERROR, "could not determine data type of format() input");
+ arg++;
+
/*
* Get the appropriate typOutput function, reusing previous one if
* same type as previous argument. That's particularly useful in the
@@ -4221,7 +4370,7 @@ text_format(PG_FUNCTION_ARGS)
case 'I':
case 'L':
text_format_string_conversion(&str, *cp, &typoutputfinfo,
- value, isNull);
+ value, isNull, flags, width);
break;
default:
ereport(ERROR,
@@ -4244,23 +4393,65 @@ text_format(PG_FUNCTION_ARGS)
PG_RETURN_TEXT_P(result);
}
+/*
+ * Add spaces on begin or on end when it is necessary
+ */
+static void
+text_format_append_string(StringInfo buf, const char *str,
+ int flags, int width)
+{
+ bool align_to_left = false;
+ int len;
+
+ /* fast path */
+ if (width == 0)
+ {
+ appendStringInfoString(buf, str);
+ return;
+ }
+ else if (width < 0 || (flags & TEXT_FORMAT_FLAG_MINUS))
+ {
+ align_to_left = true;
+ if (width < 0)
+ width = -width;
+ }
+
+ len = pg_mbstrlen(str);
+ if (align_to_left)
+ {
+ appendStringInfoString(buf, str);
+ if (len < width)
+ appendStringInfoSpaces(buf, width - len);
+ }
+ else
+ {
+ /* align_to_right */
+ if (len < width)
+ appendStringInfoSpaces(buf, width - len);
+ appendStringInfoString(buf, str);
+ }
+}
+
/* Format a %s, %I, or %L conversion. */
static void
text_format_string_conversion(StringInfo buf, char conversion,
FmgrInfo *typOutputInfo,
- Datum value, bool isNull)
+ Datum value, bool isNull,
+ int flags, int width)
{
char *str;
- /* Handle NULL arguments before trying to stringify the value. */
if (isNull)
{
- if (conversion == 'L')
- appendStringInfoString(buf, "NULL");
+ if (conversion == 's')
+ text_format_append_string(buf, "", flags, width);
+ else if (conversion == 'L')
+ text_format_append_string(buf, "NULL", flags, width);
else if (conversion == 'I')
ereport(ERROR,
(errcode(ERRCODE_NULL_VALUE_NOT_ALLOWED),
errmsg("null values cannot be formatted as an SQL identifier")));
+
return;
}
@@ -4271,18 +4462,18 @@ text_format_string_conversion(StringInfo buf, char conversion,
if (conversion == 'I')
{
/* quote_identifier may or may not allocate a new string. */
- appendStringInfoString(buf, quote_identifier(str));
+ text_format_append_string(buf, quote_identifier(str), flags, width);
}
else if (conversion == 'L')
{
char *qstr = quote_literal_cstr(str);
- appendStringInfoString(buf, qstr);
+ text_format_append_string(buf, qstr, flags, width);
/* quote_literal_cstr() always allocates a new string */
pfree(qstr);
}
else
- appendStringInfoString(buf, str);
+ text_format_append_string(buf, str, flags, width);
/* Cleanup. */
pfree(str);
diff --git a/src/test/regress/expected/text.out b/src/test/regress/expected/text.out
index b756583..e05a1e5 100644
--- a/src/test/regress/expected/text.out
+++ b/src/test/regress/expected/text.out
@@ -256,12 +256,20 @@ select format('%1$s %4$s', 1, 2, 3);
ERROR: too few arguments for format
select format('%1$s %13$s', 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12);
ERROR: too few arguments for format
+select format('%0$s', 'Hello');
+ERROR: conversion specifies argument 0, but arguments are numbered from 1
+select format('%*0$s', 'Hello');
+ERROR: conversion specifies argument 0, but arguments are numbered from 1
select format('%1s', 1);
-ERROR: unterminated conversion specifier
+ format
+--------
+ 1
+(1 row)
+
select format('%1$', 1);
ERROR: unterminated conversion specifier
select format('%1$1', 1);
-ERROR: unrecognized conversion specifier "1"
+ERROR: unterminated conversion specifier
-- check mix of positional and ordered placeholders
select format('Hello %s %1$s %s', 'World', 'Hello again');
format
@@ -328,3 +336,74 @@ from generate_series(1,200) g(i);
1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99,100,101,102,103,104,105,106,107,108,109,110,111,112,113,114,115,116,117,118,119,120,121,122,123,124,125,126,127,128,129,130,131,132,133,134,135,136,137,138,139,140,141,142,143,144,145,146,147,148,149,150,151,152,153,154,155,156,157,158,159,160,161,162,163,164,165,166,167,168,169,170,171,172,173,174,175,176,177,178,179,180,181,182,183,184,185,186,187,188,189,190,191,192,193,194,195,196,197,198,199,200
(1 row)
+-- left, right align
+select format('>>%10s<<', 'Hello')
+union all
+select format('>>%10s<<', NULL)
+union all
+select format('>>%10s<<', '')
+union all
+select format('>>%-10s<<', '')
+union all
+select format('>>%-10s<<', 'Hello')
+union all
+select format('>>%-10s<<', NULL)
+union all
+select format('>>%1$10s<<', 'Hello')
+union all
+select format('>>%1$-10I<<', 'Hello')
+union all
+select format('>>%2$*1$L<<', 10, 'Hello')
+union all
+select format('>>%2$*1$L<<', 10, NULL)
+union all
+select format('>>%2$*1$L<<', -10, NULL)
+union all
+select format('>>%*s<<', 10, 'Hello');
+ format
+----------------
+ >> Hello<<
+ >> <<
+ >> <<
+ >> <<
+ >>Hello <<
+ >> <<
+ >> Hello<<
+ >>"Hello" <<
+ >> 'Hello'<<
+ >> NULL<<
+ >>NULL <<
+ >> Hello<<
+(12 rows)
+
+select format('>>%*1$s<<', 10, 'Hello');
+ format
+----------------
+ >> Hello<<
+(1 row)
+
+select format('>>%-s<<', 'Hello');
+ format
+-----------
+ >>Hello<<
+(1 row)
+
+-- NULL is not different to zero here
+select format('>>%10L<<', NULL);
+ format
+----------------
+ >> NULL<<
+(1 row)
+
+select format('>>%2$*1$L<<', NULL, 'Hello');
+ format
+-------------
+ >>'Hello'<<
+(1 row)
+
+select format('>>%2$*1$L<<', 0, 'Hello');
+ format
+-------------
+ >>'Hello'<<
+(1 row)
+
diff --git a/src/test/regress/sql/text.sql b/src/test/regress/sql/text.sql
index a96e9f7..1c68754 100644
--- a/src/test/regress/sql/text.sql
+++ b/src/test/regress/sql/text.sql
@@ -78,6 +78,8 @@ select format('%1$s %12$s', 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12);
-- should fail
select format('%1$s %4$s', 1, 2, 3);
select format('%1$s %13$s', 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12);
+select format('%0$s', 'Hello');
+select format('%*0$s', 'Hello');
select format('%1s', 1);
select format('%1$', 1);
select format('%1$1', 1);
@@ -97,3 +99,36 @@ select format('Hello', variadic NULL);
-- variadic argument allows simulating more than FUNC_MAX_ARGS parameters
select format(string_agg('%s',','), variadic array_agg(i))
from generate_series(1,200) g(i);
+
+-- left, right align
+select format('>>%10s<<', 'Hello')
+union all
+select format('>>%10s<<', NULL)
+union all
+select format('>>%10s<<', '')
+union all
+select format('>>%-10s<<', '')
+union all
+select format('>>%-10s<<', 'Hello')
+union all
+select format('>>%-10s<<', NULL)
+union all
+select format('>>%1$10s<<', 'Hello')
+union all
+select format('>>%1$-10I<<', 'Hello')
+union all
+select format('>>%2$*1$L<<', 10, 'Hello')
+union all
+select format('>>%2$*1$L<<', 10, NULL)
+union all
+select format('>>%2$*1$L<<', -10, NULL)
+union all
+select format('>>%*s<<', 10, 'Hello');
+
+select format('>>%*1$s<<', 10, 'Hello');
+select format('>>%-s<<', 'Hello');
+
+-- NULL is not different to zero here
+select format('>>%10L<<', NULL);
+select format('>>%2$*1$L<<', NULL, 'Hello');
+select format('>>%2$*1$L<<', 0, 'Hello');