Add rename_file/2 predicate to the files library

src/clause_types.rs

@@ -175,6 +175,7 @@ pub(crate) enum SystemClauseType {
     MakeDirectory,
     MakeDirectoryPath,
     DeleteFile,
+	RenameFile,
     DeleteDirectory,
     WorkingDirectory,
     PathCanonical,
@@ -338,6 +339,7 @@ impl SystemClauseType {
             &SystemClauseType::MakeDirectory => clause_name!("$make_directory"),
             &SystemClauseType::MakeDirectoryPath => clause_name!("$make_directory_path"),
             &SystemClauseType::DeleteFile => clause_name!("$delete_file"),
+            &SystemClauseType::RenameFile => clause_name!("$rename_file"),
             &SystemClauseType::DeleteDirectory => clause_name!("$delete_directory"),
             &SystemClauseType::WorkingDirectory => clause_name!("$working_directory"),
             &SystemClauseType::PathCanonical => clause_name!("$path_canonical"),
@@ -749,6 +751,7 @@ impl SystemClauseType {
             ("$make_directory", 1) => Some(SystemClauseType::MakeDirectory),
             ("$make_directory_path", 1) => Some(SystemClauseType::MakeDirectoryPath),
             ("$delete_file", 1) => Some(SystemClauseType::DeleteFile),
+            ("$rename_file", 2) => Some(SystemClauseType::RenameFile),
             ("$delete_directory", 1) => Some(SystemClauseType::DeleteDirectory),
             ("$working_directory", 2) => Some(SystemClauseType::WorkingDirectory),
             ("$path_canonical", 2) => Some(SystemClauseType::PathCanonical),

src/lib/files.pl

@@ -51,6 +51,7 @@
                   file_exists/1,
                   directory_exists/1,
                   delete_file/1,
+				  rename_file/2,
 				  delete_directory/1,
                   make_directory/1,
                   make_directory_path/1,
@@ -101,6 +102,12 @@ delete_file(File) :-
         list_of_chars(File),
         '$delete_file'(File).
 
+rename_file(File, Renamed) :-
+        file_must_exist(File, rename_file/2),
+        list_of_chars(File),
+		list_of_chars(Renamed),
+        '$rename_file'(File, Renamed).
+
 delete_directory(Directory) :-
         directory_must_exist(Directory, delete_directory/1),
         list_of_chars(Directory),

src/machine/system_calls.rs

@@ -900,6 +900,18 @@ impl MachineState {
                     }
                 }
             }
+            &SystemClauseType::RenameFile => {
+                let file = self.heap_pstr_iter(self[temp_v!(1)]).to_string();
+                let renamed = self.heap_pstr_iter(self[temp_v!(2)]).to_string();
+
+                match fs::rename(file, renamed) {
+                    Ok(_) => {}
+                    _ => {
+                        self.fail = true;
+                        return Ok(());
+                    }
+                }
+            }
             &SystemClauseType::DeleteDirectory => {
                 let directory = self.heap_pstr_iter(self[temp_v!(1)]).to_string();