feat: partially implemented parser

src/parser/errors.rs

@@ -0,0 +1,13 @@
+use thiserror::Error;
+use crate::lexer::errors::LexerErrors;
+use crate::lexer::tokens::Token;
+
+#[derive(Debug, Error)]
+pub enum ParserErrors {
+    #[error("unexpected token: {0:?} in procedure {1}")]
+    UnexpectedTokenError(Token, String),
+    #[error("input ended prematurely")]
+    MissingTokenError,
+    #[error("lexer error")]
+    LexerError(#[from] LexerErrors),
+}