Implement unary slash expressions (#2349 and #2384)

Author: mgreter

src/ast.hpp

@@ -1281,7 +1281,7 @@ namespace Sass {
   ////////////////////////////////////////////////////////////////////////////
   class Unary_Expression : public Expression {
   public:
-    enum Type { PLUS, MINUS, NOT };
+    enum Type { PLUS, MINUS, NOT, SLASH };
   private:
     HASH_PROPERTY(Type, optype)
     HASH_PROPERTY(Expression_Obj, operand)
@@ -1300,6 +1300,7 @@ namespace Sass {
       switch (optype_) {
         case PLUS: return "plus";
         case MINUS: return "minus";
+        case SLASH: return "slash";
         case NOT: return "not";
         default: return "invalid";
       }

src/eval.cpp

@@ -892,6 +892,10 @@ namespace Sass {
         cpy->value( - cpy->value() ); // negate value
         return cpy.detach(); // return the copy
       }
+      else if (u->optype() == Unary_Expression::SLASH) {
+        std::string str = '/' + nr->to_string(ctx.c_options);
+        return SASS_MEMORY_NEW(String_Constant, u->pstate(), str);
+      }
       // nothing for positive
       return nr.detach();
     }

src/inspect.cpp

@@ -475,8 +475,9 @@ namespace Sass {
 
   void Inspect::operator()(Unary_Expression_Ptr expr)
   {
-    if (expr->optype() == Unary_Expression::PLUS) append_string("+");
-    else                                          append_string("-");
+    if (expr->optype() == Unary_Expression::PLUS)       append_string("+");
+    else if (expr->optype() == Unary_Expression::SLASH) append_string("/");
+    else                                                append_string("-");
     expr->operand()->perform(this);
   }
 

src/parser.cpp

@@ -1433,6 +1433,11 @@ namespace Sass {
       if (ex && ex->operand()) ex->is_delayed(ex->operand()->is_delayed());
       return ex;
     }
+    else if (lex< exactly<'/'> >()) {
+      Unary_Expression_Ptr ex = SASS_MEMORY_NEW(Unary_Expression, pstate, Unary_Expression::SLASH, parse_factor());
+      if (ex && ex->operand()) ex->is_delayed(ex->operand()->is_delayed());
+      return ex;
+    }
     else if (lex< sequence< kwd_not > >()) {
       Unary_Expression_Ptr ex = SASS_MEMORY_NEW(Unary_Expression, pstate, Unary_Expression::NOT, parse_factor());
       if (ex && ex->operand()) ex->is_delayed(ex->operand()->is_delayed());