format-width-20130305.patch

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 @@
          <primary>format</primary>
         </indexterm>
         <literal><function>format</function>(<parameter>formatstr</parameter> <type>text</type>
-        [, <parameter>str</parameter> <type>"any"</type> [, ...] ])</literal>
+        [, <parameter>formatarg</parameter> <type>"any"</type> [, ...] ])</literal>
        </entry>
        <entry><type>text</type></entry>
        <entry>
          Format arguments according to a format string.
-         This function is similar to the C function
-         <function>sprintf</>, but only the following conversion specifications
-         are recognized: <literal>%s</literal> interpolates the corresponding
-         argument as a string; <literal>%I</literal> escapes its argument as
-         an SQL identifier; <literal>%L</literal> escapes its argument as an
-         SQL literal; <literal>%%</literal> outputs a literal <literal>%</>.
-         A conversion can reference an explicit parameter position by preceding
-         the conversion specifier with <literal><replaceable>n</>$</>, where
-         <replaceable>n</replaceable> is the argument position.
-         See also <xref linkend="plpgsql-quote-literal-example">.
+         This function is similar to the C function <function>sprintf</>.
+         See <xref linkend="functions-string-format">.
        </entry>
        <entry><literal>format('Hello %s, %1$s', 'World')</literal></entry>
        <entry><literal>Hello World, World</literal></entry>
@@ -2847,6 +2839,186 @@
     </tgroup>
    </table>
 
+   <sect2 id="functions-string-format">
+    <title><function>format</function></title>
+
+    <indexterm>
+     <primary>format</primary>
+    </indexterm>
+
+    <para>
+     The function <function>format</> produces formatted output according to
+     a format string in a similar way to the C function <function>sprintf</>.
+    </para>
+
+    <para>
+<synopsis>
+format(<parameter>formatstr</> <type>text</> [, <parameter>formatarg</> <type>"any"</> [, ...] ])
+</synopsis>
+     <replaceable>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 <firstterm>format specifiers</> are used.
+     Format specifiers act as placeholders in the string, allowing subsequent
+     function arguments to be formatted and inserted into the result.
+    </para>
+
+    <para>
+     Format specifiers are introduced by a <literal>%</> character and take
+     the form
+<synopsis>
+%[<replaceable>parameter</>][<replaceable>flags</>][<replaceable>width</>]<replaceable>type</>
+</synopsis>
+     <variablelist>
+      <varlistentry>
+       <term><replaceable>parameter</replaceable> (optional)</term>
+       <listitem>
+        <para>
+         An expression of the form <literal><replaceable>n</>$</> where
+         <replaceable>n</> is the index of the argument to use for the format
+         specifier's value.  An index of 1 means the first argument after
+         <replaceable>formatstr</>.  If the <replaceable>parameter</> field is
+         omitted, the default is to use the next argument.
+        </para>
+<screen>
+SELECT format('Testing %s, %s, %s', 'one', 'two', 'three');
+<lineannotation>Result: </><computeroutput>Testing one, two, three</>
+
+SELECT format('Testing %3$s, %2$s, %1$s', 'one', 'two', 'three');
+<lineannotation>Result: </><computeroutput>Testing three, two, one</>
+</screen>
+
+        <para>
+         Note that unlike the C function <function>sprintf</> defined in the
+         Single UNIX Specification, the <function>format</> function in
+         <productname>PostgreSQL</> allows format specifiers with and without
+         explicit <replaceable>parameter</> fields to be mixed in the same
+         format string.  A format specifier without a
+         <replaceable>parameter</> field always uses the next argument after
+         the last argument consumed.  In addition, the
+         <productname>PostgreSQL</> <function>format</> function does not
+         require all function arguments to be referred to in the format
+         string.
+        </para>
+<screen>
+SELECT format('Testing %3$s, %2$s, %s', 'one', 'two', 'three');
+<lineannotation>Result: </><computeroutput>Testing three, two, three</>
+</screen>
+       </listitem>
+      </varlistentry>
+
+      <varlistentry>
+       <term><replaceable>flags</replaceable> (optional)</term>
+       <listitem>
+        <para>
+         Additional options controlling how the format specifier's output is
+         formatted.  Currently the only supported flag is an minus sign
+         (<literal>-</>) which will cause the format specifier's output to be
+         left-aligned.  This has no effect unless the <replaceable>width</>
+         field is also specified.
+        </para>
+<screen>
+SELECT format('|%10s|%-10s|', 'foo', 'bar');
+<lineannotation>Result: </><computeroutput>|       foo|bar       |</>
+</screen>
+       </listitem>
+      </varlistentry>
+
+      <varlistentry>
+       <term><replaceable>width</replaceable> (optional)</term>
+       <listitem>
+        <para>
+         Specifies the <emphasis>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
+         (<literal>*</>) to use the next function argument as the width; or an
+         expression of the form <literal>*<replaceable>n</>$</> to use the
+         <replaceable>n</>th function argument as the width.
+        </para>
+
+        <para>
+         If the width comes from a function argument, that argument is
+         consumed <emphasis>before</> the argument that is used for the format
+         specifier's value.  If the width argument is negative, the result is
+         left aligned, as if the <literal>-</> flag had been specified.
+        </para>
+<screen>
+SELECT format('|%10s|', 'foo');
+<lineannotation>Result: </><computeroutput>|       foo|</>
+
+SELECT format('|%*s|', 10, 'foo');
+<lineannotation>Result: </><computeroutput>|       foo|</>
+
+SELECT format('|%*s|', -10, 'foo');
+<lineannotation>Result: </><computeroutput>|foo       |</>
+
+SELECT format('|%-*s|', 10, 'foo');
+<lineannotation>Result: </><computeroutput>|foo       |</>
+
+SELECT format('|%-*s|', -10, 'foo');
+<lineannotation>Result: </><computeroutput>|foo       |</>
+
+SELECT format('|%*2$s|', 'foo', 10, 'bar');
+<lineannotation>Result: </><computeroutput>|       bar|</>
+
+SELECT format('|%3$*2$s|', 'foo', 10, 'bar');
+<lineannotation>Result: </><computeroutput>|       bar|</>
+</screen>
+       </listitem>
+      </varlistentry>
+
+      <varlistentry>
+       <term><replaceable>type</replaceable> (required)</term>
+       <listitem>
+        <para>
+         The type of format conversion to use to produce the format
+         specifier's output.  The following types are supported:
+         <itemizedlist>
+          <listitem>
+           <para>
+            <literal>s</literal> formats the argument value as a simple
+            string.  A null value is treated as an empty string.
+           </para>
+          </listitem>
+          <listitem>
+           <para>
+            <literal>I</literal> escapes the value as an SQL identifier.  It
+            is an error for the value to be null.
+           </para>
+          </listitem>
+          <listitem>
+           <para>
+            <literal>L</literal> escapes the value as an SQL literal.  A null
+            value is displayed as the literal value <literal>NULL</>.
+           </para>
+          </listitem>
+         </itemizedlist>
+        </para>
+<screen>
+SELECT format('Hello %s', 'World');
+<lineannotation>Result: </lineannotation><computeroutput>Hello World</computeroutput>
+
+SELECT format('DROP TABLE %I', 'Foo bar');
+<lineannotation>Result: </lineannotation><computeroutput>DROP TABLE "Foo bar"</computeroutput>
+
+SELECT format('SELECT %L', E'O\'Reilly');
+<lineannotation>Result: </lineannotation><computeroutput>SELECT 'O''Reilly'</computeroutput>
+</screen>
+
+        <para>
+         The <literal>%I</> and <literal>%L</> format specifiers may be used
+         to safely construct dynamic SQL statements.  See
+         <xref linkend="plpgsql-quote-literal-example">.
+        </para>
+       </listitem>
+      </varlistentry>
+     </variablelist>
+    </para>
+
+    <para>
+     In addition to the format specifiers above, the special escape sequence
+     <literal>%%</> may be used to output a literal <literal>%</> character.
+    </para>
+   </sect2>
   </sect1>
 
 
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');