From 9f34a3f5acfde207c5c51b14aaba3e3302bc482c Mon Sep 17 00:00:00 2001
From: Danila Fedorin <danila.fedorin@gmail.com>
Date: Tue, 14 Aug 2018 19:12:35 -0700
Subject: [PATCH] Add operator support.

---
 src/main.cpp | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/src/main.cpp b/src/main.cpp
index 725382e..4b49efe 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -222,6 +222,9 @@ class abacus {
     public:
         abacus();
         void add_function(const std::string& name, libab_function_ptr ptr, const std::string& type);
+        void add_operator_infix(const std::string& op, const std::string& func, int assoc, int prec);
+        void add_operator_prefix(const std::string& op, const std::string& func);
+        void add_operator_postfix(const std::string& op, const std::string& func);
         abacus_ref run(const std::string& code);
         template <typename ... Ts>
         abacus_ref call(const std::string& bane, Ts...params);
@@ -251,6 +254,16 @@ void abacus::add_function(const std::string& name, libab_function_ptr ptr, const
     }
 }
 
+void abacus::add_operator_infix(const std::string& op, const std::string& func, int assoc, int prec) {
+    libab_register_operator_infix(&ab, op.c_str(), prec, assoc, func.c_str());
+}
+void abacus::add_operator_prefix(const std::string& op, const std::string& func) {
+    libab_register_operator_prefix(&ab, op.c_str(), func.c_str());
+}
+void abacus::add_operator_postfix(const std::string& op, const std::string& func) {
+    libab_register_operator_postfix(&ab, op.c_str(), func.c_str());
+}
+
 abacus_ref abacus::run(const std::string& code) {
     abacus_ref value;
     libab_run_scoped(&ab, code.c_str(), scope, value);
@@ -302,6 +315,12 @@ int main() {
     ab.add_function("divide", function_divide, "(num, num)->num");
     ab.add_function("negate", function_negate, "(num)->num");
 
+    ab.add_operator_infix("+", "plus", 1, -1);
+    ab.add_operator_infix("-", "minus", 1, -1);
+    ab.add_operator_infix("*", "times", 2, -1);
+    ab.add_operator_infix("/", "divide", 2, -1);
+    ab.add_operator_prefix("-", "negate");
+
     while(!close_requested) {
         std::cout << "> ";
         std::getline(std::cin, buffer);