Improve formatting of array output

Before this change, e.g. `SELECT '{1}'::numeric` would output `[Decimal(1)]`.
Now it instead outputs `{1}`.

changelog.rst

@@ -5,6 +5,7 @@ Features:
 ---------
 
 * Add fish-style auto-suggestion from history. (Thanks: `Amjith Ramanujam`_)
+* Improved formatting of arrays in output (Thanks: `Joakim Koljonen`_)
 * Remove the ``...`` in the continuation prompt and use empty space instead. (Thanks: `Amjith Ramanujam`_)
 
 Bug Fixes:

pgcli/main.py

@@ -946,6 +946,19 @@ def format_output(title, cur, headers, status, settings):
     case_function = settings.case_function
     formatter = TabularOutputFormatter(format_name=table_format)
 
+    def format_array(val):
+        if val is None:
+            return settings.missingval
+        if not isinstance(val, list):
+            return val
+        return '{' + ','.join(unicode(format_array(e)) for e in val) + '}'
+
+    def format_arrays(data, headers, column_types, **kwargs):
+        for row in data:
+            row[:] = [format_array(val) if isinstance(val, list) else val for val in row]
+
+        return data, headers
+
     output_kwargs = {
         'sep_title': 'RECORD {n}',
         'sep_character': '-',
@@ -953,7 +966,7 @@ def format_output(title, cur, headers, status, settings):
         'missing_value': settings.missingval,
         'integer_format': settings.dcmlfmt,
         'float_format': settings.floatfmt,
-        'preprocessors': (format_numbers, ),
+        'preprocessors': (format_numbers, format_arrays),
         'disable_numparse': True,
         'preserve_whitespace': True
     }

tests/test_main.py

@@ -1,6 +1,8 @@
+# coding=utf-8
 import os
 import platform
 import mock
+from decimal import Decimal
 
 import pytest
 try:
@@ -56,6 +58,52 @@ def test_format_output():
     assert results == expected
 
 
+def test_format_array_output(executor):
+    statement = u"""
+    SELECT
+        array[1, 2, 3]::bigint[] as bigint_array,
+        '{{1,2},{3,4}}'::numeric[] as nested_numeric_array,
+        '{å,魚,текст}'::text[] as 配列
+    UNION ALL
+    SELECT '{}', NULL, array[NULL]
+    """
+    results = run(executor, statement)
+    expected = [
+        u'+----------------+------------------------+--------------+\n'
+        u'| bigint_array   | nested_numeric_array   | 配列         |\n'
+        u'|----------------+------------------------+--------------|\n'
+        u'| {1,2,3}        | {{1,2},{3,4}}          | {å,魚,текст} |\n'
+        u'| {}             | <null>                 | {<null>}     |\n'
+        u'+----------------+------------------------+--------------+',
+        u'SELECT 2'
+    ]
+    assert results == expected
+
+
+def test_format_array_output_expanded(executor):
+    statement = u"""
+    SELECT
+        array[1, 2, 3]::bigint[] as bigint_array,
+        '{{1,2},{3,4}}'::numeric[] as nested_numeric_array,
+        '{å,魚,текст}'::text[] as 配列
+    UNION ALL
+    SELECT '{}', NULL, array[NULL]
+    """
+    results = run(executor, statement, expanded=True)
+    expected = [
+        u'-[ RECORD 1 ]-------------------------\n'
+        u'bigint_array         | {1,2,3}\n'
+        u'nested_numeric_array | {{1,2},{3,4}}\n'
+        u'配列                   | {å,魚,текст}\n'
+        u'-[ RECORD 2 ]-------------------------\n'
+        u'bigint_array         | {}\n'
+        u'nested_numeric_array | <null>\n'
+        u'配列                   | {<null>}\n',
+        u'SELECT 2'
+    ]
+    assert results == expected
+
+
 def test_format_output_auto_expand():
     settings = OutputSettings(
         table_format='psql', dcmlfmt='d', floatfmt='g', max_width=100)