Re: Readline and conditional tab results based on input

Hi,

On 2008/08/11, at 13:42, Takao Kouji wrote:
>> And with Readline.completion_proc i have code that will return only dirs
>> in this directory. But I would like to invoke this specific code part
>> only
>> when a user typed in i.e. "cd "
>>
>> So if i have a directory called "foobar" it should work here:
>>
>>
>> "cd foo<TAB>"  # completed to foobar
>>
>> but if the user would type
>>
>> "blabalblabla foo<TAB>" # there should be no result
>
> I want to add some methods that satisfy the Marc Heiler's demands.
> The patch contributed to the RubyForge is taken. 
>
>  [#3212] Readline does not provide enough context to the completion_proc
>  http://rubyforge.org/tracker/index.php?func=detail&aid=3212&group_id=426&atid=1698
>
> First of all, I will take it into ruby 1.9. Afterwards, backport to 1.8.

I will add the follows methods.
* line_buffer: Returns the full line that is being edited.
  (same as rl_line_buffer)
* point: Returns the index of the current cursor position 
  in Readline.line_buffer. (same as rl_point)

The match_start is computed by subtracting the length of input-string
from Readline.point.
The match_end and Readline.line_buffer are same.

Attached the patch for ruby 1.9 (r18525).

Thanks, TAKAO Kouji.
-----

Index: ext/readline/readline.c
===================================================================
--- ext/readline/readline.c	(revision 18525)
+++ ext/readline/readline.c	(working copy)
@@ -367,6 +367,56 @@
     return rb_attr_get(mReadline, completion_case_fold);
 }
 
+/*
+ * call-seq:
+ *   Readline.line_buffer -> string
+ *
+ * Returns the full line that is being edited. This is useful from
+ * within the complete_proc for determining the context of the
+ * completion request.
+ *
+ * The length of +Readline.line_buffer+ and GNU Readline's rl_end are
+ * same.
+ */
+static VALUE
+readline_s_get_line_buffer(VALUE self)
+{
+#ifdef HAVE_RL_LINE_BUFFER
+    rb_secure(4);
+    if (rl_line_buffer == NULL)
+	return Qnil;
+    return rb_tainted_str_new2(rl_line_buffer);
+#else
+    rb_notimplement();
+    return Qnil; /* not reached */
+#endif /* HAVE_RL_LINE_BUFFER */
+}
+
+/*
+ * call-seq:
+ *   Readline.point -> int
+ *
+ * Returns the index of the current cursor position in
+ * +Readline.line_buffer+.
+ *
+ * The index in +Readline.line_buffer+ which matches the start of
+ * input-string passed to completion_proc is computed by subtracting
+ * the length of input-string from +Readline.point+.
+ *
+ *   start = (the length of input-string) - Readline.point
+ */
+static VALUE
+readline_s_get_point(VALUE self)
+{
+#ifdef HAVE_RL_POINT
+    rb_secure(4);
+    return INT2NUM(rl_point);
+#else
+    rb_notimplement();
+    return Qnil; /* not reached */
+#endif /* HAVE_RL_POINT */
+}
+
 static char **
 readline_attempted_completion_function(const char *text, int start, int end)
 {
@@ -1196,6 +1246,10 @@
 			       readline_s_set_completion_case_fold, 1);
     rb_define_singleton_method(mReadline, "completion_case_fold",
 			       readline_s_get_completion_case_fold, 0);
+    rb_define_singleton_method(mReadline, "line_buffer",
+			       readline_s_get_line_buffer, 0);
+    rb_define_singleton_method(mReadline, "point",
+			       readline_s_get_point, 0);
     rb_define_singleton_method(mReadline, "vi_editing_mode",
 			       readline_s_vi_editing_mode, 0);
     rb_define_singleton_method(mReadline, "vi_editing_mode?",
Index: ext/readline/extconf.rb
===================================================================
--- ext/readline/extconf.rb	(revision 18525)
+++ ext/readline/extconf.rb	(working copy)
@@ -59,6 +59,8 @@
 have_readline_var("rl_attempted_completion_over")
 have_readline_var("rl_library_version")
 have_readline_var("rl_editing_mode")
+have_readline_var("rl_line_buffer")
+have_readline_var("rl_point")
 # workaround for native windows.
 /mswin|bccwin|mingw/ !~ RUBY_PLATFORM && have_readline_var("rl_event_hook")
 have_readline_func("rl_cleanup_after_signal")
Index: test/readline/test_readline.rb
===================================================================
--- test/readline/test_readline.rb	(revision 18525)
+++ test/readline/test_readline.rb	(working copy)
@@ -3,6 +3,8 @@
 =begin
   class << Readline
     [
+     "line_buffer",
+     "point",
      "vi_editing_mode",
      "emacs_editing_mode",
      "completion_append_character=",
@@ -61,6 +63,8 @@
        ["completer_quote_characters"],
        ["filename_quote_characters=", "\\"],
        ["filename_quote_characters"],
+       ["line_buffer"],
+       ["point"],
       ]
     method_args.each do |method_name, *args|
       assert_raises(SecurityError, NotImplementedError,
@@ -74,41 +78,83 @@
     end
   end
 
-  def test_readline
-    stdin = Tempfile.new("test_readline_stdin")
-    stdout = Tempfile.new("test_readline_stdout")
-    begin
-      stdin.write("hello\n")
-      stdin.close
-      stdout.close
-      line = replace_stdio(stdin.path, stdout.path) {
-        Readline.readline("> ", true)
-      }
-      assert_equal("hello", line)
-      assert_equal(true, line.tainted?)
-      stdout.open
-      assert_equal("> ", stdout.read(2))
-      assert_equal(1, Readline::HISTORY.length)
-      assert_equal("hello", Readline::HISTORY[0])
-      assert_raises(SecurityError) do
-        Thread.start {
-          $SAFE = 1
-          replace_stdio(stdin.path, stdout.path) do
-            Readline.readline("> ".taint)
-          end
-        }.join
+  if !/EditLine/n.match(Readline::VERSION)
+    def test_readline
+      stdin = Tempfile.new("test_readline_stdin")
+      stdout = Tempfile.new("test_readline_stdout")
+      begin
+        stdin.write("hello\n")
+        stdin.close
+        stdout.close
+        line = replace_stdio(stdin.path, stdout.path) {
+          Readline.readline("> ", true)
+        }
+        assert_equal("hello", line)
+        assert_equal(true, line.tainted?)
+        stdout.open
+        assert_equal("> ", stdout.read(2))
+        assert_equal(1, Readline::HISTORY.length)
+        assert_equal("hello", Readline::HISTORY[0])
+        assert_raises(SecurityError) do
+          Thread.start {
+            $SAFE = 1
+            replace_stdio(stdin.path, stdout.path) do
+              Readline.readline("> ".taint)
+            end
+          }.join
+        end
+        assert_raises(SecurityError) do
+          Thread.start {
+            $SAFE = 4
+            replace_stdio(stdin.path, stdout.path) { Readline.readline("> ") }
+          }.join
+        end
+      ensure
+        stdin.close(true)
+        stdout.close(true)
       end
-      assert_raises(SecurityError) do
-        Thread.start {
-          $SAFE = 4
-          replace_stdio(stdin.path, stdout.path) { Readline.readline("> ") }
-        }.join
+    end 
+
+    # line_buffer
+    # point
+    def test_line_buffer__point
+      begin
+        Readline.line_buffer
+        Readline.point
+      rescue NotImplementedError
+        return
       end
-    ensure
-      stdin.close(true)
-      stdout.close(true)
+
+      stdin = Tempfile.new("test_readline_stdin")
+      stdout = Tempfile.new("test_readline_stdout")
+      begin
+        actual_text = nil
+        actual_line_buffer = nil
+        actual_point = nil
+        Readline.completion_proc = proc { |text|
+          actual_text = text
+          actual_point = Readline.point
+          actual_buffer_line = Readline.line_buffer
+          stdin.write(" finish\n")
+          stdin.close
+          stdout.close
+          return ["complete"]
+        }
+        stdin.write("first second\t")
+        stdin.flush
+        line = replace_stdio(stdin.path, stdout.path) {
+          Readline.readline("> ", false)
+        }
+        assert_equal("first second", actual_line_buffer)
+        assert_equal(12, actual_point)
+        assert_equal("first complete finish", Readline.line_buffer)
+        assert_equal(21, Readline.point)
+      ensure
+        stdin.close(true)
+        stdout.close(true)
+      end
     end
-  end if !/EditLine/n.match(Readline::VERSION)
+  end
 
   def test_input=
     assert_raise(TypeError) do