[Python3] Added support to make book at python 3 environment, change instruction for describe the process how to make with python 3.

Author: TheVice

README.md

@@ -3,19 +3,19 @@ Issues and pull requests are more than welcome!
 
 ## Building the Book
 
-The book is written in Markdown (in `book/`). A little Python script (`script/format.py`) converts that along with a SASS file (`asset/style.scss`) and HTML template (`asset/template.html`) to the final HTML (in `html/`). To run the format script locally, you'll need to have Python 2.7-ish, and install Python Markdown, Pygments, and SmartyPants:
+The book is written in Markdown (in `book/`). A little Python script (`script/format.py`) converts that along with a SASS file (`asset/style.scss`) and HTML template (`asset/template.html`) to the final HTML (in `html/`). To run the format script locally, you'll need to have Python 3.5-ish, and install Python Markdown, Pygments, and SmartyPants:
 
-    $ pip install markdown
-    $ pip install pygments
-    $ pip install smartypants
+    $ pip3 install markdown
+    $ pip3 install pygments
+    $ pip3 install smartypants
 
 You may need `sudo` for those. Once that's done, you can run:
 
-    $ python script/format.py
+    $ python3 script/format.py
 
 Make sure to run this from the root directory of the repo. That will regenerate all of the chapter and section intro HTML files. If you're editing stuff, the script can also be run in watch mode:
 
-    $ python script/format.py --watch
+    $ python3 script/format.py --watch
 
 That will monitor the file system for changes to the markdown files, SASS file, or HTML template, and reprocess them as needed.
 

script/format.py

@@ -152,15 +152,18 @@ def format_file(path, nav, skip_up_to_date):
         elif command == 'outline':
           isoutline = True
         else:
-          print "UNKNOWN COMMAND:", command, args
+          print ("UNKNOWN COMMAND:", command, args)
 
       elif extension != "xml" and stripped.startswith('#'):
         # Build the page navigation from the headers.
         index = stripped.find(" ")
         headertype = stripped[:index]
         header = pretty(stripped[index:].strip())
         anchor = header.lower().replace(' ', '-')
-        anchor = anchor.translate(None, '.?!:/"')
+        if 2 == sys.version_info[0]:
+          anchor = anchor.translate(None, '.?!:/"')
+        else:
+          anchor = anchor.translate('.?!:/"')
 
         # Add an anchor to the header.
         contents += indentation + headertype
@@ -224,19 +227,19 @@ def format_file(path, nav, skip_up_to_date):
     num_chapters += 1
     if word_count < 50:
       empty_chapters += 1
-      print "  {}".format(basename)
+      print ("  {}".format(basename))
     elif word_count < 2000:
       empty_chapters += 1
-      print "{}-{} {} ({} words)".format(
-        YELLOW, DEFAULT, basename, word_count)
+      print ("{}-{} {} ({} words)".format(
+        YELLOW, DEFAULT, basename, word_count))
     else:
       total_words += word_count
-      print "{}✓{} {} ({} words)".format(
-        GREEN, DEFAULT, basename, word_count)
+      print ("{}✓{} {} ({} words)".format(
+        GREEN, DEFAULT, basename, word_count))
   else:
     # Section header chapters aren't counted like regular chapters.
-    print "{}•{} {} ({} words)".format(
-      GREEN, DEFAULT, basename, word_count)
+    print ("{}•{} {} ({} words)".format(
+      GREEN, DEFAULT, basename, word_count))
 
 
 def clean_up_xml(output):
@@ -417,8 +420,8 @@ def include_code(pattern, index, indentation):
         else:
           code_line = line[blockindent:]
           if len(code_line) > 64:
-            print "Warning long source line ({} chars):\n{}".format(
-                len(code_line), code_line)
+            print ("Warning long source line ({} chars):\n{}".format(
+                len(code_line), code_line))
           code += indentation + '    ' + code_line
 
     else:
@@ -466,7 +469,7 @@ def check_sass():
     return
 
   subprocess.call(['sass', 'asset/style.scss', 'html/style.css'])
-  print "{}✓{} style.css".format(GREEN, DEFAULT)
+  print ("{}✓{} style.css".format(GREEN, DEFAULT))
 
 
 searchpath = ('book/*.markdown')
@@ -494,5 +497,5 @@ def check_sass():
   estimated_word_count = total_words + (empty_chapters * average_word_count)
   percent_finished = total_words * 100 / estimated_word_count
 
-  print "{}/~{} words ({}%)".format(
-    total_words, estimated_word_count, percent_finished)
+  print ("{}/~{} words ({}%)".format(
+    total_words, estimated_word_count, percent_finished))