Use .. as secondary prompt for ruby

This is a non backward compatibility change.

Before, one or more *consecutive* primary prompts >> were considered a
single example.

This is too fragile and dangerous.

Consider the following (previous this commit)

>> puts "a"     # byexample: +pass
>> puts "b"

Which output is none: the +pass is affecting the 2-lines example.

Now, if you add a single newline (probably for aesthetics purposes)

>> puts "a"     # byexample: +pass

>> puts "b"

The example is split in 2 and the second is has no the +pass option
enabled.

For this reason now each >> is a single example; for multiline examples
we need to use ..

We go from this

>> def f
>>   1
>> end

to this

>> def f
..   1
.. end

byexample/modules/ruby.py

@@ -1,8 +1,8 @@
 """
 Example:
   >> def hello
-  >>     'hello bla world'
-  >> end;
+  ..     'hello bla world'
+  .. end;
 
   >> hello
   => "hello<...>world"
@@ -53,13 +53,13 @@ class RubyPromptFinder(ExampleFinder):
     @constant
     def example_regex(self):
         return re.compile(r'''
-            # Snippet consists of one or more PS1 lines >>
+            # Snippet consists of one PS1 line >> and zero or more PS2 lines
             (?P<snippet>
                 (?:^(?P<indent> [ ]*) >>[ ]     .*)    # PS1 line
-                (?:\n           [ ]*  >>      .*)*)    # and more PS1 lines
+                (?:\n           [ ]*  \.\.    .*)*)    # zero or more PS2 lines
             \n?
             # Want consists of any non-blank lines that do not start with PS1
-            # The '=>' indicator is included (implicitly)
+            # The '=>' indicator is included (implicitly) and may not exist
             (?P<expected> (?:(?![ ]*$)     # Not a blank line
                           (?![ ]*>>)       # Not a line starting with PS1
                          .+$\n?            # But any other line

docs/languages/ruby.md

@@ -7,11 +7,8 @@ Check its [download page](https://www.ruby-lang.org/en/downloads/)
 
 ## Find interactive examples
 
-For ``Ruby``, ``byexample`` uses the ``>>`` string as the primary and
-secondary prompts.
-
-Because of this, all the consecutive lines that start with ``>>`` will belong
-to the same example and they will be executed together.
+For ``Ruby``, ``byexample`` uses the ``>>`` string as the primary prompt
+and ``..`` as the secondary prompt.
 
 
 ```ruby
@@ -21,11 +18,11 @@ to the same example and they will be executed together.
 => 3
 
 >> def g(a, b, c)
->>     c += a
->>     c += b
->>
->>     return c
->> end
+..     c += a
+..     c += b
+..
+..     return c
+.. end
 
 >> g(1, 2, 3)
 => 6
@@ -99,30 +96,6 @@ semicolons. It is easy to get confused with this weird effect.
 
 ```
 
-This is important because you may want to use ``;`` to suppress the expression's
-value in a multi expression example:
-
-
-```ruby
->> a = 1;
->> b = 2;
->> a + b
-=> 3
-
-```
-
-In contrast with:
-
-```ruby
->> a = 1
->> b = 2
->> a + b
-=> 1
-=> 2
-=> 3
-
-```
-
 # Pretty print
 
 ``byexample`` changes the default IRB's ``inspector`` and uses ``pp``

test/test.md

@@ -76,8 +76,8 @@ File docs/languages/cpp.md, 2/2 test ran in <...> seconds
 File docs/languages/gdb.md, 8/8 test ran in <...> seconds
 [PASS] Pass: 8 Fail: 0 Skip: 0
 ~
-File docs/languages/ruby.md, 12/12 test ran in <...> seconds
-[PASS] Pass: 12 Fail: 0 Skip: 0
+File docs/languages/ruby.md, 14/14 test ran in <...> seconds
+[PASS] Pass: 14 Fail: 0 Skip: 0
 ~
 File docs/languages/python.md, 41/41 test ran in <...> seconds
 [PASS] Pass: 40 Fail: 0 Skip: 1