add formatting for unary expression

ast/src/expressions/expression.rs

@@ -66,7 +66,7 @@ impl<'ast> fmt::Display for Expression<'ast> {
         match *self {
             Expression::Value(ref expression) => write!(f, "{}", expression),
             Expression::Identifier(ref expression) => write!(f, "{}", expression),
-            Expression::Unary(ref expression) => write!(f, "!{}", expression.expression),
+            Expression::Unary(ref expression) => write!(f, "{}", expression),
             Expression::Binary(ref expression) => write!(f, "{} == {}", expression.left, expression.right),
             Expression::Ternary(ref expression) => write!(
                 f,

ast/src/expressions/unary_expression.rs

@@ -3,6 +3,7 @@ use crate::{ast::Rule, expressions::Expression, operations::UnaryOperation, Span
 use pest::Span;
 use pest_ast::FromPest;
 use serde::Serialize;
+use std::fmt;
 
 #[derive(Clone, Debug, FromPest, PartialEq, Serialize)]
 #[pest_ast(rule(Rule::expression_unary))]
@@ -13,3 +14,9 @@ pub struct UnaryExpression<'ast> {
     #[serde(with = "SpanDef")]
     pub span: Span<'ast>,
 }
+
+impl<'ast> fmt::Display for UnaryExpression {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "{}{}", self.operation, self.expression)
+    }
+}

ast/src/operations/unary_operation.rs

@@ -2,6 +2,7 @@ use crate::ast::Rule;
 
 use pest_ast::FromPest;
 use serde::Serialize;
+use std::fmt;
 
 #[derive(Clone, Debug, FromPest, PartialEq, Serialize)]
 #[pest_ast(rule(Rule::operation_unary))]
@@ -10,6 +11,15 @@ pub enum UnaryOperation {
     Not(Not),
 }
 
+impl fmt::Display for UnaryOperation {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        match self {
+            UnaryOperation::Minus(_) => write!(f, "-"),
+            UnaryOperation::Not(_) => write!(f, "!"),
+        }
+    }
+}
+
 #[derive(Clone, Debug, FromPest, PartialEq, Serialize)]
 #[pest_ast(rule(Rule::operation_not))]
 pub struct Not {}