Refactor alias_markdown_table_generator

README.md

@@ -45,7 +45,7 @@ The aliases are defined in [English.rb](lib/English.rb), and are as follows, fir
 ### Builtin to Alias Table
 
 | Builtin | Alias                    |
-| :-------: | ----------------------   |
+| :-----: | ------------------------ |
 |   $!    | $ERROR_INFO              |
 |   $$    | $PID                     |
 |   $$    | $PROCESS_ID              |

Rakefile

@@ -1 +1,5 @@
 require "bundler/gem_tasks"
+
+file "README.md" => "lib/English.rb" do
+  ruby "bin/alias_markdown_table_generator", "README.md"
+end

exe/alias_markdown_table_generator → bin/alias_markdown_table_generator

@@ -22,46 +22,44 @@ require 'stringio'
 
 # Parses the English.rb file for aliases into an array of alias/builtin tuples.
 class FileParser
-  ALIAS_SOURCE_FILESPEC = File.absolute_path(File.join(File.basename(__FILE__), '../lib/English.rb'))
+  ALIAS_SOURCE_FILESPEC = File.join(__dir__, '../lib/English.rb')
 
   def self.parse(code_text_lines=File.readlines(ALIAS_SOURCE_FILESPEC))
-    lines = code_text_lines \
-      .map(&:strip) \
-      .reject { |line| line.start_with?('#') } \
-      .select { |line| line.match(/^alias/) }
-    tuples = lines.each_with_object([]) do |line, tuples|
-      tuples << line.split[1..2]
-    end
-    tuples.sort
+    code_text_lines.grep(/^\s*alias\s+(\S+)\s+(\S+)/) {$~.captures}
   end
 end
 
 
 class MarkdownTableGenerator
   # Returns a string containing a markdown table of the aliases, with headings "Alias" and "Built-In".
   # @param [Array] tuples array of alias/builtin tuples
-  # @param [Boolean] alias_to_builtin true if alias to builtin, false if builtin to alias
-  def self.generate(tuples_orig, alias_to_builtin=true)
-    col1_label, col2_label = alias_to_builtin ? ['Builtin', 'Alias'] : ['Alias', 'Builtin']
-
-    # Sort by the first column, whatever that is.
-    tuples = alias_to_builtin ? tuples_orig.map(&:reverse).sort.map(&:reverse) : tuples_orig
+  # @param [Boolean] builtin_to_alias true if builtin to alias, false if alias to builtin
+  def self.generate(tuples, builtin_to_alias=true)
 
-    tuples = tuples.map(&:reverse) if alias_to_builtin
+    col1_label, col2_label = 'Alias', 'Builtin'
     col1_length = [tuples.map { |(a, _b)| a.length }.max, col1_label.length].max
     col2_length = [tuples.map { |(_a, b)| b.length }.max, col2_label.length].max
 
-    col1_heading_line = alias_to_builtin ? ":#{'-' * col1_length}:" : ('-' * col1_length)
-    col2_heading_line = alias_to_builtin ? '-' * (col2_length - 2) : ":#{'-' * (col2_length - 2)}:"
+    col1_heading_line = ('-' * col1_length)
+    col2_heading_line = ":#{'-' * (col2_length - 2)}:"
 
-    format_line = ->(item1, item2) do
-      if alias_to_builtin
+    if builtin_to_alias
+      tuples = tuples.map(&:reverse)
+      col1_label, col2_label = col2_label, col1_label
+      col1_length, col2_length = col2_length, col1_length
+      col1_heading_line, col2_heading_line = col2_heading_line, col1_heading_line
+      format_line = ->(item1, item2) do
         "| #{item1.center(col1_length)} | #{item2.ljust(col2_length)} |"
-      else
+      end
+    else
+      format_line = ->(item1, item2) do
         "| #{item1.ljust(col1_length)} | #{item2.center(col2_length)} |"
       end
     end
 
+    # Sort by the first column, whatever that is.
+    tuples.sort!
+
     markdown_string = StringIO.new
     markdown_string << format_line.call(col1_label, col2_label) << "\n"
     markdown_string << format_line.call(col1_heading_line, col2_heading_line) << "\n"
@@ -74,6 +72,14 @@ end
 
 if __FILE__ == $0
   alias_tuples = FileParser.parse
+  replace = !ARGV.empty?
+  if replace
+    ARGF.inplace_mode = "~"
+    ARGF.each do |line|
+      break if /^### Builtin to Alias Table/ =~ line
+      puts line
+    end
+  end
   puts <<~OUTPUT
     ### Builtin to Alias Table
 
@@ -83,4 +89,18 @@ if __FILE__ == $0
 
     #{MarkdownTableGenerator.generate(alias_tuples, false)}
   OUTPUT
+  if replace
+    puts
+    ARGF.each do |line|
+      if replace
+        case line
+        when /^##?\s/, /^### (?!Alias to Builtin Table)/
+          puts line
+          replace = false
+        end
+      else
+        puts line
+      end
+    end
+  end
 end