Rename ClosedFormula to OpenFormula

src/ast.rs

@@ -556,7 +556,7 @@ impl Formula
 	}
 }
 
-pub struct ClosedFormula
+pub struct OpenFormula
 {
 	pub free_variable_declarations: std::rc::Rc<VariableDeclarations>,
 	pub formula: Formula,

src/parse/formulas.rs

@@ -1,8 +1,7 @@
 use super::terms::*;
 use super::tokens::*;
 
-pub fn formula<D>(input: &str, declarations: &D)
+pub fn formula<D>(input: &str, declarations: &D) -> Result<crate::OpenFormula, crate::parse::Error>
-	-> Result<crate::ClosedFormula, crate::parse::Error>
 where
 	D: crate::FindOrCreateFunctionDeclaration + crate::FindOrCreatePredicateDeclaration,
 {
@@ -18,7 +17,7 @@ where
 		_ => unreachable!(),
 	};
 
-	Ok(crate::ClosedFormula
+	Ok(crate::OpenFormula
 	{
 		formula,
 		free_variable_declarations,