Allow calling functions without arguments

src/context/mod.rs

@@ -102,7 +102,10 @@ impl Context for VariableMap {
                 None
             }
         } else {
-            self.variables.get(identifier)
+            self.variables.get(identifier).or_else(|| {
+                self.call_function(identifier, &Value::Empty);
+                None
+            })
         }
     }
 

src/toolbox.rs

@@ -0,0 +1,37 @@
+use crate::Result;
+
+use std::collections::HashMap;
+
+pub fn build(variables: &HashMap<String, Value>) -> Result<Value> {
+    let name = {
+        let name = if let Some(value) = variables.get("name") {
+            format!("--name {}", value)
+        } else {
+            String::with_capacity(0)
+        };
+
+        Value::String(name)
+    };
+    let image = {
+        let image = if let Some(value) = variables.get("image") {
+            format!("--image {}", value)
+        } else {
+            String::with_capacity(0)
+        };
+
+        Value::String(image)
+    };
+
+    // let toolbox_command = format!("toolbox create --image {} {}", &image, &name);
+    // Command::new("fish")
+    //     .arg("-c")
+    //     .arg(&toolbox_command)
+    //     .spawn()
+    //     .unwrap()
+    //     .wait()
+    //     .unwrap();
+
+    println!("{} {}", image, name);
+
+    Ok(Value::String("Built container.".to_string()))
+}