Added CHANGELOG entry and doc.

CHANGES

@@ -3,6 +3,8 @@ x.y.z ()
 
 New:
 
+- Added support for recursive functions (#406)
+
 - Add peak and peak.stereo operators (#364)
 
 - Change `track_sensitive` parameter to a boolean getter (fixed value or anonymous function).

doc/content/language.txt

@@ -24,11 +24,25 @@ The constants and their syntax are quite common:
 
 Strings might be surrounded by double or single quotes. In both cases, you can escape the quote you're using: <code>"He said: \"Hello, you\"."</code> is valid but <code>'He said: "Hello, you".'</code> is equivalent and nicer.
 
-Also, you can include variables in a string using the <code>#{...}</code>
+You can include variables in a string using the <code>#{...}</code>
 syntax:
 <code>"foo #{quote(my_var)} bar"</code> is equivalent to
 <code>"foo " ^ quote(my_var) ^ " bar"</code>.
 
+Finally, strings can be interpolated using the following syntax:
+
+%%
+# s = 'This is an $(name) string. \
+       This is a $(if $(value),"$(value)","undefined") value.';;
+# s % [("name","interpolated")];;
+- : string = "This is an interpolated string.This is a undefined value."
+# s % [("name","interpolated"),("value","defined")];;
+- : string = "This is an interpolated string.This is a defined value."
+%%
+
+Most notably, <code>output.file</code> can use string interpolation to specify a different file name
+using the source's metadata.
+
 h4. Expressions
 
 You can form expressions by using:
@@ -59,6 +73,17 @@ end
 # The full type of foo is ()->string.
 %%
 
+Recursive functions can be defined using the <code>rec</code> keywork:
+%%(lan_rec_func.liq)
+def rec fact(n) =
+  if n == 1 then
+    1
+  else
+    n * fact(n-1)
+  end
+end
+%%
+
 
 **Type of an application.** The type of an application is the return type of function if all mandatory arguments are applied. With the function @foo@ previously defined, @foo()@ is a string. Otherwise, the application is "partial", and the expression still has a function type.