Add auto-vertical layout when table exceeds terminal width

README.md

@@ -86,6 +86,10 @@ The return value is a native PG::Result object, which supports mapping or extrac
 => #<PG::Result:0x000000012ebf6a38 status=PGRES_TUPLES_OK ntuples=3 nfields=1 cmd_tuples=3>
 ```
 
+## TODO
+
+- [ ] `--list` / `--table` CLI flags to override auto-detection
+
 ## Development
 
 After checking out the repo, run `bin/setup` to install dependencies. Then, run `rake test` to run the tests. You can also run `bin/console` for an interactive prompt that will allow you to experiment.

lib/taql.rb

@@ -1,4 +1,6 @@
+require "io/console"
 require_relative "taql/cli"
+require_relative "taql/list"
 require_relative "taql/table"
 require_relative "taql/version"
 require_relative "taql/railtie" if defined?(Rails)
@@ -10,13 +12,26 @@ class << self
     def execute(query, options = {}, connection: nil)
       (connection || default_connection).execute(query).tap do |result|
         if (results = result.entries).any?
-          $stdout.puts Table.new(results, markdown: options[:markdown])
+          $stdout.puts formatter(results, markdown: options[:markdown])
         end
       end
     end
 
     private
 
+    def formatter(results, markdown: false)
+      table = Table.new(results, markdown: markdown)
+      if !markdown && table.table_width > terminal_width
+        List.new(results, terminal_width: terminal_width)
+      else
+        table
+      end
+    end
+
+    def terminal_width
+      IO.console&.winsize&.last || Float::INFINITY
+    end
+
     def default_connection
       @default_connection&.call || raise("Taql not properly initialized with Rails")
     end

lib/taql/list.rb

@@ -0,0 +1,49 @@
+module Taql
+  class List
+    DASH = "-".freeze
+    PIPE = " | ".freeze
+
+    def initialize(entries, terminal_width: nil)
+      @entries = entries.map { |entry| entry.transform_values(&:to_s) }
+      @terminal_width = terminal_width
+    end
+
+    def print
+      output if entries.any?
+    end
+
+    private
+
+    attr_reader :entries
+
+    def headers
+      @headers ||= entries.flat_map(&:keys).uniq
+    end
+
+    def max_header_width
+      @max_header_width ||= headers.map(&:length).max
+    end
+
+    def divider_width
+      @terminal_width&.finite? ? @terminal_width : 32
+    end
+
+    def output
+      records = entries.map { |entry| [separator, *rows(entry)].join("\n") }
+
+      [*records, separator].join("\n")
+    end
+
+    def separator
+      DASH * divider_width
+    end
+
+    def rows(entry)
+      headers.map do |header|
+        "#{header.upcase.rjust(max_header_width)}#{PIPE}#{entry[header]}"
+      end
+    end
+
+    alias_method :to_s, :print
+  end
+end

lib/taql/table.rb

@@ -12,6 +12,10 @@ def initialize(entries, markdown: false)
       @markdown = markdown
     end
 
+    def table_width
+      column_widths.sum + (3 * columns.count) + 1
+    end
+
     def body
       entries.map(&:values)
     end

test/test_list.rb

@@ -0,0 +1,74 @@
+require "test_helper"
+
+class TestList < Minitest::Test
+  def test_vertical_output
+    list = Taql::List.new([
+      {"name" => "Alice", "age" => 30},
+      {"name" => "Bob", "age" => 25}
+    ], terminal_width: 40)
+
+    result = list.print
+
+    assert_includes result, "NAME | Alice"
+    assert_includes result, " AGE | 25"
+  end
+
+  def test_single_record
+    list = Taql::List.new([
+      {"name" => "Alice", "age" => 30}
+    ], terminal_width: 40)
+
+    result = list.print
+
+    assert_includes result, "NAME | Alice"
+    assert_includes result, " AGE | 30"
+  end
+
+  def test_divider_fills_terminal_width
+    list = Taql::List.new([
+      {"name" => "Alice"}
+    ], terminal_width: 40)
+
+    lines = list.print.lines.map(&:chomp)
+
+    assert_equal 40, lines.first.length
+    assert_equal 40, lines.last.length
+  end
+
+  def test_trailing_separator
+    list = Taql::List.new([
+      {"name" => "Alice"}
+    ], terminal_width: 40)
+
+    last_line = list.print.lines.last.chomp
+
+    assert_match(/\A-+\z/, last_line)
+  end
+
+  def test_renders_nothing_when_empty
+    list = Taql::List.new([])
+
+    assert_nil list.print
+  end
+
+  def test_default_divider_without_terminal_width
+    list = Taql::List.new([
+      {"name" => "Alice"}
+    ])
+
+    result = list.print
+
+    assert_match(/\A-+\n/, result)
+  end
+
+  def test_headers_are_right_padded
+    list = Taql::List.new([
+      {"name" => "Alice", "email" => "alice@example.com"}
+    ], terminal_width: 40)
+
+    result = list.print
+
+    assert_includes result, " NAME | Alice"
+    assert_includes result, "EMAIL | alice@example.com"
+  end
+end

test/test_table.rb

@@ -77,4 +77,12 @@ def test_headers_with_heterogeneous_entries
 
     assert_equal ["name", "age", "email"], table.headers
   end
+
+  def test_table_width_calculation
+    table = Taql::Table.new([
+      {"name" => "Alice", "age" => 30}
+    ])
+
+    assert_equal 15, table.table_width
+  end
 end