Relax whitespace requirement around operators.

Fixes #637 #397

spec/examples/pipe

@@ -64,3 +64,15 @@ component Main {
     ""
   }
 }
+-------------------------------------------------------------------------------
+component Main {
+  fun test (value : String) {
+    value
+  }
+
+  fun render : Html {
+    "test" |> test
+
+    <div/>
+  }
+}

src/parser/top_level.cr

@@ -79,7 +79,6 @@ module Mint
             component ||
             constant ||
             property ||
-            operator ||
             provider ||
             function ||
             comment ||

src/parsers/operator.cr

@@ -26,19 +26,6 @@ module Mint
       "!"  => 16,
     }
 
-    # Parses an operator.
-    #
-    # All operators must follow a whitespace because we don't have an end of
-    # line token, so the expression can leak through to the next entity, for
-    # example:
-    #
-    #   const NAME = "Joe"
-    #
-    #   /* This is a comment. */
-    #   fun greet (name : String = NAME) { ... }
-    #
-    # In this case the start token of the comment (/*) can be interpreted as an
-    # operation (/) and the whitespace prevents that.
     def operator : String?
       parse do
         whitespace
@@ -47,10 +34,22 @@ module Mint
           position
 
         operator =
-          OPERATORS.keys.find { |item| word! item }
+          OPERATORS.keys.find { |item| word? item }
 
         next unless operator
-        next if operator != "|>" && !whitespace?
+
+        # It's not an operator if it's a closing tag `</div>`
+        # or fragment `<>` or anything starting with `<`
+        # or a comment `// comment`, `/* comment */`.
+        case operator
+        when "<"
+          next if base_expression
+          next if next_char == '/'
+        when "/"
+          next if next_char.in?('*', '/')
+        end
+
+        word! operator
 
         case operator
         when "or"