Separate error

parser/src/error.rs

@@ -0,0 +1,18 @@
+use crate::Rule;
+
+pub type ParseResult<'a, T> = Result<T, ParseError<'a>>;
+
+#[derive(Debug, Clone)]
+pub enum ParseError<'a> {
+    PreAst(pest::error::Error<Rule>),
+    Ast {
+        span: pest::Span<'a>,
+        error_code: ErrorCode,
+        error_message: String,
+    },
+}
+
+#[derive(Debug, Clone)]
+pub enum ErrorCode {
+    InvalidStatement = 200,
+}