Limit the allowed sigils

Author: José Valim

CHANGELOG.md

@@ -20,6 +20,7 @@
 * Backwards incompatible changes
   * [Dict] Implementations of `equal?/2` and `merge/2` in `HashDict` and `ListDict` are no longer polymorphic. To get polymorphism, use the functions in `Dict` instead
   * [Kernel] Remove `**` from the list of allowed operators
+  * [Kernel] Limit sigils delimiters to one of the following: `<>`, `{}`, `[]`, `()`, `||`, `//`, `"` and `'`
   * [Range] `Range` is no longer a record, instead use `first .. last` if you need pattern matching
   * [Set] Implementations of `difference/2`, `disjoint?/2`, `equal?/2`, `intersection/2`, `subset?/2` and `union/2` in `HashSet` are no longer polymorphic. To get polymorphism, use the functions in `Set` instead
 

lib/elixir/include/elixir.hrl

@@ -80,7 +80,8 @@
 -define(is_atom(S), ?is_identifier(S) orelse (S == $@)).
 
 -define(is_identifier(S), ?is_digit(S) orelse ?is_upcase(S) orelse ?is_downcase(S) orelse (S == $_)).
--define(is_terminator(S), (S == $?) orelse (S == $!) orelse (S == $:)).
+-define(is_sigil(S), (S == $/) orelse (S == $<) orelse (S == $") orelse (S == $') orelse
+                     (S == $[) orelse (S == $() orelse (S == ${) orelse (S == $|)).
 
 %% Quotes
 -define(is_quote(S), S == $" orelse S == $').

lib/elixir/src/elixir_tokenizer.erl

@@ -145,7 +145,7 @@ tokenize([$%,S,H,H,H|T] = Original, Line, Scope, Tokens) when ?is_quote(H), ?is_
       { error, Reason, Original, Tokens }
   end;
 
-tokenize([$%,S,H|T] = Original, Line, Scope, Tokens) when not(?is_identifier(H)), not(?is_terminator(H)), ?is_upcase(S) orelse ?is_downcase(S) ->
+tokenize([$%,S,H|T] = Original, Line, Scope, Tokens) when ?is_sigil(H), ?is_upcase(S) orelse ?is_downcase(S) ->
   case elixir_interpolation:extract(Line, Scope, ?is_downcase(S), T, sigil_terminator(H)) of
     { NewLine, Parts, Rest } ->
       { Final, Modifiers } = collect_modifiers(Rest, []),

lib/elixir/test/elixir/kernel/sigils_test.exs

@@ -21,6 +21,8 @@ defmodule Kernel.SigilsTest do
     assert %S{foo} == "foo"
     assert %S'foo' == "foo"
     assert %S"foo" == "foo"
+    assert %S<foo> == "foo"
+    assert %S/foo/ == "foo"
     assert %S|foo| == "foo"
     assert %S(f#{o}o) == "f\#{o}o"
     assert %S(f\no) == "f\\no"