Extend format() to handle field width and left/right alignment.

This change adds some more standard sprintf() functionality to format().

Pavel Stehule, reviewed by Dean Rasheed and Kyotaro Horiguchi

2 files changed, 130 insertions, 6 deletions

diff --git a/src/test/regress/expected/text.out b/src/test/regress/expected/text.out
index b7565830d6f..4b1c62bf53c 100644
--- a/src/test/regress/expected/text.out
+++ b/src/test/regress/expected/text.out
@@ -209,7 +209,7 @@ ERROR:  too few arguments for format
 select format('Hello %s');
 ERROR:  too few arguments for format
 select format('Hello %x', 20);
-ERROR:  unrecognized conversion specifier "x"
+ERROR:  unrecognized conversion type specifier "x"
 -- check literal and sql identifiers
 select format('INSERT INTO %I VALUES(%L,%L)', 'mytab', 10, 'Hello');
                  format                 
@@ -256,12 +256,14 @@ 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('%1s', 1);
-ERROR:  unterminated conversion specifier
+select format('%0$s', 'Hello');
+ERROR:  format specifies argument 0, but arguments are numbered from 1
+select format('%*0$s', 'Hello');
+ERROR:  format specifies argument 0, but arguments are numbered from 1
 select format('%1$', 1);
-ERROR:  unterminated conversion specifier
+ERROR:  unterminated format specifier
 select format('%1$1', 1);
-ERROR:  unrecognized conversion specifier "1"
+ERROR:  unterminated format specifier
 -- check mix of positional and ordered placeholders
 select format('Hello %s %1$s %s', 'World', 'Hello again');
             format             
@@ -328,3 +330,106 @@ 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)
 
+-- check field widths and left, right alignment
+select format('>>%10s<<', 'Hello');
+     format     
+----------------
+ >>     Hello<<
+(1 row)
+
+select format('>>%10s<<', NULL);
+     format     
+----------------
+ >>          <<
+(1 row)
+
+select format('>>%10s<<', '');
+     format     
+----------------
+ >>          <<
+(1 row)
+
+select format('>>%-10s<<', '');
+     format     
+----------------
+ >>          <<
+(1 row)
+
+select format('>>%-10s<<', 'Hello');
+     format     
+----------------
+ >>Hello     <<
+(1 row)
+
+select format('>>%-10s<<', NULL);
+     format     
+----------------
+ >>          <<
+(1 row)
+
+select format('>>%1$10s<<', 'Hello');
+     format     
+----------------
+ >>     Hello<<
+(1 row)
+
+select format('>>%1$-10I<<', 'Hello');
+     format     
+----------------
+ >>"Hello"   <<
+(1 row)
+
+select format('>>%2$*1$L<<', 10, 'Hello');
+     format     
+----------------
+ >>   'Hello'<<
+(1 row)
+
+select format('>>%2$*1$L<<', 10, NULL);
+     format     
+----------------
+ >>      NULL<<
+(1 row)
+
+select format('>>%2$*1$L<<', -10, NULL);
+     format     
+----------------
+ >>NULL      <<
+(1 row)
+
+select format('>>%*s<<', 10, 'Hello');
+     format     
+----------------
+ >>     Hello<<
+(1 row)
+
+select format('>>%*1$s<<', 10, 'Hello');
+     format     
+----------------
+ >>     Hello<<
+(1 row)
+
+select format('>>%-s<<', 'Hello');
+  format   
+-----------
+ >>Hello<<
+(1 row)
+
+select format('>>%10L<<', NULL);
+     format     
+----------------
+ >>      NULL<<
+(1 row)
+
+select format('>>%2$*1$L<<', NULL, 'Hello');
+   format    
+-------------
+ >>'Hello'<<
+(1 row)
+
+select format('>>%2$*1$L<<', 0, 'Hello');
+   format    
+-------------
+ >>'Hello'<<
+(1 row)
+
diff --git a/src/test/regress/sql/text.sql b/src/test/regress/sql/text.sql
index a96e9f7d1e7..c4ed74b39d4 100644
--- a/src/test/regress/sql/text.sql
+++ b/src/test/regress/sql/text.sql
@@ -78,7 +78,8 @@ select format('%1$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$s', 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12);
-select format('%1s', 1);
+select format('%0$s', 'Hello');
+select format('%*0$s', 'Hello');
 select format('%1$', 1);
 select format('%1$1', 1);
 -- check mix of positional and ordered placeholders
@@ -97,3 +98,21 @@ 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);
+-- check field widths and left, right alignment
+select format('>>%10s<<', 'Hello');
+select format('>>%10s<<', NULL);
+select format('>>%10s<<', '');
+select format('>>%-10s<<', '');
+select format('>>%-10s<<', 'Hello');
+select format('>>%-10s<<', NULL);
+select format('>>%1$10s<<', 'Hello');
+select format('>>%1$-10I<<', 'Hello');
+select format('>>%2$*1$L<<', 10, 'Hello');
+select format('>>%2$*1$L<<', 10, NULL);
+select format('>>%2$*1$L<<', -10, NULL);
+select format('>>%*s<<', 10, 'Hello');
+select format('>>%*1$s<<', 10, 'Hello');
+select format('>>%-s<<', 'Hello');
+select format('>>%10L<<', NULL);
+select format('>>%2$*1$L<<', NULL, 'Hello');
+select format('>>%2$*1$L<<', 0, 'Hello');