utils: use dhall substitutes for config typesdhall-substitutes

this uses my own version of dhall_rust [1], which has actual support for
adding in new types in rust code, which are derived via serde, instead
of just gluing in extra code for every file that is read in (in
particular, this results in actually useful error messages).

1 files changed, 6 insertions, 2 deletions

diff --git a/utils/src/main.rs b/utils/src/main.rs
index 4428ac3..ea267d8 100644
--- a/utils/src/main.rs
+++ b/utils/src/main.rs
@@ -64,13 +64,17 @@ fn main () {
     // imported: just wrap our input code into a dhall "let"-statement.
     // Probably doesn't scale very vell, though ...
     let code = format!(
-        "let Question = {} \nlet Answers = {} \nlet Lang = {}\nin {}",
+        "let Question = {} \nlet Lang = {}\nin {}",
         Question::static_type(),
-        AnswerSpace::static_type(),
         Lang::static_type(),
         config_file
     );
     match serde_dhall::from_str(&code)
+        .substitute_names(vec![
+            ("Question".to_string(),Question::static_type()),
+            ("Answers".to_string(), AnswerSpace::static_type()),
+            ("Lang".to_string(), Lang::static_type())
+        ].iter().cloned().collect())
         .static_type_annotation()
         .parse::<Survey>()
     {