add lua sandbox, tabs, stuff

computers/commands/expr/conf.json

@@ -0,0 +1,7 @@
+{
+    "name": "expr",
+    "license": "MIT",
+    "version": 0.1,
+    "engine": 0.42,
+    "help": "exicutes mathmatical expresions"
+}

computers/commands/expr/init.lua

@@ -0,0 +1,14 @@
+function expr(pos, input, data)
+    local output
+    local func = computers.sandbox.loadstring("return " .. input, {env={}})
+
+    if func then output = func() end
+
+    if type(output) ~= "number" or output == nil then
+        return "Error: invalid or missing input"
+    end
+
+    return tostring(output)
+end
+
+return expr