Fix #2. Disallow multiple expressions in a placeable.

fluent.asdl

@@ -7,9 +7,7 @@ module Fluent
           | Comment(comment)
           | Junk(string body)
 
-    pat = Pattern(elem* elements, bool quoted)
-    elem = Text(string)
-         | Placeable(expr* expressions)
+    pat = Pattern(expr* elements, bool quoted)
 
     expr = MessageReference(iden id)
          | ExternalArgument(iden id)

fluent.ebnf

@@ -32,22 +32,19 @@ unquoted-text        ::= ([^{] | '\{')+;
 quoted-text          ::= ([^{"] | '\{' | '\"')+;
 block-text           ::= NL __ '|' unquoted-pattern;
 
-placeable            ::= '{' __ placeable-list __ '}';
-placeable-list       ::= placeable-expression (__ ',' __ placeable-list)?;
-placeable-expression ::= expression
-                      |  select-expression
-                      ;
+placeable            ::= '{' __ expression __ '}';
 expression           ::= quoted-pattern
                       |  number
                       |  identifier
                       |  variable
-                      |  call-expression
+                      |  select-expression
                       |  member-expression
+                      |  call-expression
                       ;
 select-expression    ::= expression __ ' ->' __ variants-list;
+member-expression    ::= identifier '[' keyword ']';
 call-expression      ::= builtin '(' __ arglist? __ ')';
 arglist              ::= argument (__ ',' __ arglist)?;
 argument             ::= expression
                       |  keyword-argument;
 keyword-argument     ::= identifier __ ':' __ quoted-pattern;
-member-expression    ::= identifier '[' keyword ']';

functions.rst

@@ -153,9 +153,6 @@ Implicit use
 In order to simplify most common scenarios, FTL will run some default
 functions while resolving placeables.
 
-For the list of implicit functions, the implict example has exactly the same
-result as the explicit one.
-
 ``NUMBER``
     If the variable passed from the developer is a number and is used in
     a placeable, FTL will implicitly call a `NUMBER` function on it.
@@ -198,18 +195,11 @@ result as the explicit one.
       log-time2 = Entry time: { DATETIME($date) }
 
 ``LIST``
-    If the variable passed from the developer is a number and is used in
+    If the variable passed from the developer is an array and is used in
     a placeable, FTL will implicitly call a `LIST` function on it.
 
-    Also, if the placeable is a list of variables, FTL will implicitly
-    call a `LIST` function on it.
-
     Example::
 
-      users = { LIST($user1, $user2, $user3) }
-
-      users2 = { $user1, $user2, $user3 }
-
       users = { LIST($users) }
 
       users2 = { $users }

guide.rst

@@ -361,14 +361,15 @@ Complex Example
     liked-photo = { LEN($people) ->
         [1]     { $people } likes
         [2]     { $people } like
-        [3]     { TAKE(2, $people), "one more person" } like
-
-       *[other] { TAKE(2, $people),
-                  "{ LEN(DROP(2, $people)) ->
-                      [1]    one more person like
-                     *[other]  { LEN(DROP(2, $people)) } more people like
-                   }"
-                }
+        [3]     { LIST(TAKE(2, $people), "one more person") } like
+
+       *[other] { LIST(
+            TAKE(2, $people),
+            "{ LEN(DROP(2, $people)) ->
+                [1]    one more person like
+               *[other]  { LEN(DROP(2, $people)) } more people like
+            }"
+        )}
     } your photo.
 
 ::
@@ -388,7 +389,10 @@ people.
 
 This example is very sophisticated and in fact could be simplified like so::
 
-    liked-photo = { LEN($people) } like your photo
+    liked-photo = { LEN($people) ->
+        [one] One person likes
+       *[other] { LEN($people) } people like
+    } your photo.
 
 It would work well enough for English and could work for other languages 
 without increasing its complexity.