Change how word splitting works when completing

Previously, I relied on replxx to correctly split words based on
word-splitting characters. However, as completion gets more complex and
completions possibly insert word-splitting characters, it starts to do
weird stuff like deleting some of your input. Fortunately, replxx allows
you to set the context length for completion - that is, how many
character it should consider as part of the word you're completing.

Change-Id: I035ac5059c8ab125efedb90cbeb2910f20da04a7
diff --git a/src/parser.hpp b/src/parser.hpp
index 3c009e6..c2cd8d6 100644
--- a/src/parser.hpp
+++ b/src/parser.hpp
@@ -24,6 +24,12 @@
     ~TooManyArgumentsException() override;
 };
 
+struct Completions {
+    bool operator==(const Completions& b) const;
+    std::set<std::string> m_completions;
+    int m_contextLength;
+};
+
 class Parser {
 public:
     Parser(const std::shared_ptr<const Schema> schema);
@@ -31,7 +37,7 @@
     void changeNode(const dataPath_& name);
     std::string currentNode() const;
     std::set<std::string> availableNodes(const boost::optional<boost::variant<boost::variant<dataPath_, schemaPath_>, module_>>& path, const Recursion& option) const;
-    std::set<std::string> completeCommand(const std::string& line, std::ostream& errorStream) const;
+    Completions completeCommand(const std::string& line, std::ostream& errorStream) const;
 
 private:
     const std::shared_ptr<const Schema> m_schema;