add file write function

src/gpsl/external_function.rs

@@ -38,6 +38,18 @@ pub const STD_FUNC: fn(
 ) -> ExternalFuncReturn = |name, args, accept, reject, data| {
     let name = name.as_str();
     match name {
+        "write" => {
+            let file_name = args[0].clone();
+            let content = args[1].clone();
+            let mut file =
+                std::fs::File::create(file_name.extract_text().unwrap().as_str()).unwrap();
+            file.write_all(content.extract_text().unwrap().as_bytes())
+                .unwrap();
+            ExternalFuncReturn {
+                status: ExternalFuncStatus::SUCCESS,
+                value: None,
+            }
+        }
         "length" => {
             let vec = args[0].clone();
             match vec {

src/gpsl/variable.rs

@@ -54,4 +54,22 @@ impl Variable {
             _ => None,
         }
     }
+
+    pub fn extract_text(&self) -> Option<String> {
+        match self {
+            Variable::Text { value } => Some(value.clone()),
+            Variable::Number { value } => Some(value.to_string()),
+            Variable::PureEncrypted { value } => Some(value.to_string()),
+            Variable::PairedEncrypted { value } => Some(value.to_string()),
+            Variable::U512 { value } => Some(value.to_string()),
+            Variable::Vec { value, .. } => {
+                let mut result = String::new();
+                for v in value {
+                    result.push_str(&v.extract_text().unwrap());
+                }
+                Some(result)
+            }
+            _ => None,
+        }
+    }
 }