Rethink \crosstabview's argument parsing logic.

\crosstabview interpreted its arguments in an unusual way, including
doing case-insensitive matching of unquoted column names, which is
surely not the right thing.  Rip that out in favor of doing something
equivalent to the dequoting/case-folding rules used by other psql
commands.  To keep it simple, change the syntax so that the optional
sort column is specified as a separate argument, instead of the
also-quite-unusual syntax that attached it to the colH argument with
a colon.

Also, rework the error messages to be closer to project style.

src/test/regress/expected/psql_crosstab.out

@@ -35,7 +35,7 @@ SELECT v, EXTRACT(year FROM d), count(*)
 -- ordered months in horizontal header, quoted column name
 SELECT v, to_char(d, 'Mon') AS "month name", EXTRACT(month FROM d) AS num,
  count(*) FROM ctv_data  GROUP BY 1,2,3 ORDER BY 1
- \crosstabview v "month name":num 4
+ \crosstabview v "month name" 4 num
  v  | Jan | Apr | Jul | Dec 
 ----+-----+-----+-----+-----
  v0 |     |     |   2 |   1
@@ -50,7 +50,7 @@ SELECT EXTRACT(year FROM d) AS year, to_char(d,'Mon') AS "month name",
   FROM ctv_data
   GROUP BY EXTRACT(year FROM d), to_char(d,'Mon'), EXTRACT(month FROM d)
 ORDER BY month
-\crosstabview "month name" year:year format
+\crosstabview "month name" year format year
  month name |      2014       |      2015      
 ------------+-----------------+----------------
  Jan        |                 | sum=3 avg=3.0
@@ -74,7 +74,7 @@ SELECT v, h, string_agg(c, E'\n') FROM ctv_data GROUP BY v, h ORDER BY 1,2,3
 -- horizontal ASC order from window function
 SELECT v,h, string_agg(c, E'\n') AS c, row_number() OVER(ORDER BY h) AS r
 FROM ctv_data GROUP BY v, h ORDER BY 1,3,2
- \crosstabview v h:r c
+ \crosstabview v h c r
  v  | h0  | h1  |  h2  | h4  |     
 ----+-----+-----+------+-----+-----
  v0 |     |     |      | qux+| qux
@@ -87,7 +87,7 @@ FROM ctv_data GROUP BY v, h ORDER BY 1,3,2
 -- horizontal DESC order from window function
 SELECT v, h, string_agg(c, E'\n') AS c, row_number() OVER(ORDER BY h DESC) AS r
 FROM ctv_data GROUP BY v, h ORDER BY 1,3,2
- \crosstabview v h:r c
+ \crosstabview v h c r
  v  |     | h4  |  h2  | h1  | h0  
 ----+-----+-----+------+-----+-----
  v0 | qux | qux+|      |     | 
@@ -100,7 +100,7 @@ FROM ctv_data GROUP BY v, h ORDER BY 1,3,2
 -- horizontal ASC order from window function, NULLs pushed rightmost
 SELECT v,h, string_agg(c, E'\n') AS c, row_number() OVER(ORDER BY h NULLS LAST) AS r
 FROM ctv_data GROUP BY v, h ORDER BY 1,3,2
- \crosstabview v h:r c
+ \crosstabview v h c r
  v  | h0  | h1  |  h2  | h4  |     
 ----+-----+-----+------+-----+-----
  v0 |     |     |      | qux+| qux
@@ -112,7 +112,7 @@ FROM ctv_data GROUP BY v, h ORDER BY 1,3,2
 
 -- only null, no column name, 2 columns: error
 SELECT null,null \crosstabview
-The query must return at least two columns to be shown in crosstab
+\crosstabview: query must return at least three columns
 -- only null, no column name, 3 columns: works
 SELECT null,null,null \crosstabview
  ?column? |  
@@ -163,23 +163,39 @@ FROM ctv_data GROUP BY v, h ORDER BY h,v
     |     |     |      | dbl | 
 (3 rows)
 
+-- refer to columns by quoted names, check downcasing of unquoted name
+SELECT 1 as "22", 2 as b, 3 as "Foo"
+ \crosstabview "22" B "Foo"
+ 22 | 2 
+----+---
+  1 | 3
+(1 row)
+
 -- error: bad column name
 SELECT v,h,c,i FROM ctv_data
  \crosstabview v h j
-Invalid column name: j
+\crosstabview: column name not found: "j"
+-- error: need to quote name
+SELECT 1 as "22", 2 as b, 3 as "Foo"
+ \crosstabview 1 2 Foo
+\crosstabview: column name not found: "foo"
+-- error: need to not quote name
+SELECT 1 as "22", 2 as b, 3 as "Foo"
+ \crosstabview 1 "B" "Foo"
+\crosstabview: column name not found: "B"
 -- error: bad column number
 SELECT v,h,i,c FROM ctv_data
  \crosstabview 2 1 5
-Invalid column number: 5
+\crosstabview: invalid column number: "5"
 -- error: same H and V columns
 SELECT v,h,i,c FROM ctv_data
  \crosstabview 2 h 4
-The same column cannot be used for both vertical and horizontal headers
+\crosstabview: vertical and horizontal headers must be different columns
 -- error: too many columns
 SELECT a,a,1 FROM generate_series(1,3000) AS a
  \crosstabview
-Maximum number of columns (1600) exceeded
+\crosstabview: maximum number of columns (1600) exceeded
 -- error: only one column
 SELECT 1 \crosstabview
-The query must return at least two columns to be shown in crosstab
+\crosstabview: query must return at least three columns
 DROP TABLE ctv_data;

src/test/regress/sql/psql_crosstab.sql

@@ -23,7 +23,7 @@ SELECT v, EXTRACT(year FROM d), count(*)
 -- ordered months in horizontal header, quoted column name
 SELECT v, to_char(d, 'Mon') AS "month name", EXTRACT(month FROM d) AS num,
  count(*) FROM ctv_data  GROUP BY 1,2,3 ORDER BY 1
- \crosstabview v "month name":num 4
+ \crosstabview v "month name" 4 num
 
 -- ordered months in vertical header, ordered years in horizontal header
 SELECT EXTRACT(year FROM d) AS year, to_char(d,'Mon') AS "month name",
@@ -32,7 +32,7 @@ SELECT EXTRACT(year FROM d) AS year, to_char(d,'Mon') AS "month name",
   FROM ctv_data
   GROUP BY EXTRACT(year FROM d), to_char(d,'Mon'), EXTRACT(month FROM d)
 ORDER BY month
-\crosstabview "month name" year:year format
+\crosstabview "month name" year format year
 
 -- combine contents vertically into the same cell (V/H duplicates)
 SELECT v, h, string_agg(c, E'\n') FROM ctv_data GROUP BY v, h ORDER BY 1,2,3
@@ -41,17 +41,17 @@ SELECT v, h, string_agg(c, E'\n') FROM ctv_data GROUP BY v, h ORDER BY 1,2,3
 -- horizontal ASC order from window function
 SELECT v,h, string_agg(c, E'\n') AS c, row_number() OVER(ORDER BY h) AS r
 FROM ctv_data GROUP BY v, h ORDER BY 1,3,2
- \crosstabview v h:r c
+ \crosstabview v h c r
 
 -- horizontal DESC order from window function
 SELECT v, h, string_agg(c, E'\n') AS c, row_number() OVER(ORDER BY h DESC) AS r
 FROM ctv_data GROUP BY v, h ORDER BY 1,3,2
- \crosstabview v h:r c
+ \crosstabview v h c r
 
 -- horizontal ASC order from window function, NULLs pushed rightmost
 SELECT v,h, string_agg(c, E'\n') AS c, row_number() OVER(ORDER BY h NULLS LAST) AS r
 FROM ctv_data GROUP BY v, h ORDER BY 1,3,2
- \crosstabview v h:r c
+ \crosstabview v h c r
 
 -- only null, no column name, 2 columns: error
 SELECT null,null \crosstabview
@@ -76,10 +76,22 @@ SELECT v,h, string_agg(i::text, E'\n') AS i, string_agg(c, E'\n') AS c
 FROM ctv_data GROUP BY v, h ORDER BY h,v
  \crosstabview 1 "h" 4
 
+-- refer to columns by quoted names, check downcasing of unquoted name
+SELECT 1 as "22", 2 as b, 3 as "Foo"
+ \crosstabview "22" B "Foo"
+
 -- error: bad column name
 SELECT v,h,c,i FROM ctv_data
  \crosstabview v h j
 
+-- error: need to quote name
+SELECT 1 as "22", 2 as b, 3 as "Foo"
+ \crosstabview 1 2 Foo
+
+-- error: need to not quote name
+SELECT 1 as "22", 2 as b, 3 as "Foo"
+ \crosstabview 1 "B" "Foo"
+
 -- error: bad column number
 SELECT v,h,i,c FROM ctv_data
  \crosstabview 2 1 5