ADD: int arith core functions.

core/core.cpp

@@ -1,8 +1,80 @@
+#include <cmath>
 #include "lib/Function.hpp"
 #include "lib/Loader.hpp"
+#include "lib/Value.hpp"
+
+extern "C" void num_arith(jk::Loader& loader)
+{
+  loader.declare("+", [](auto args){
+    int res = 0;
+
+    for (auto arg: args)
+      {
+        res += arg->as_int();
+      }
+
+    return jk::Value::make_int(res);
+  });
+
+  loader.declare("-", [](auto args){
+    int res = args[0]->as_int();
+
+    for (size_t i=1; i<args.size(); i++)
+      {
+        res -= args[i]->as_int();
+      }
+
+    return jk::Value::make_int(res);
+  });
+
+  loader.declare("*", [](auto args){
+    int res = 1;
+
+    for (auto arg: args)
+      {
+        res *= arg->as_int();
+      }
+
+    return jk::Value::make_int(res);
+  });
+
+  loader.declare("/", [](auto args){
+    int res = args[0]->as_int();
+
+    for (size_t i=1; i<args.size(); i++)
+      {
+        res /= args[i]->as_int();
+      }
+
+    return jk::Value::make_int(res);
+  });
+
+  loader.declare("^", [](auto args){
+    int res = args[0]->as_int();
+
+    for (size_t i=1; i<args.size(); i++)
+      {
+        res = std::pow(res, args[i]->as_int());
+      }
+
+    return jk::Value::make_int(res);
+  });
+
+  loader.declare("%", [](auto args){
+    int res = args[0]->as_int();
+
+    for (size_t i=1; i<args.size(); i++)
+      {
+        res %= args[i]->as_int();
+      }
+
+    return jk::Value::make_int(res);
+  });
+}
 
 extern "C" void lib(jk::Loader& loader)
 {
+  num_arith(loader);
   loader.declare("dump", [](auto args){
     std::string sep;
 

lib/Lexer.cpp

@@ -175,6 +175,10 @@ namespace jk
       return std::isalpha(c)
         || c == '_'
         || c == '-'
+        || c == '+'
+        || c == '*'
+        || c == '^'
+        || c == '%'
         || c == '?'
         || c == '!'
         || c == '/';