1 files changed, 57 insertions, 0 deletions
diff --git a/sloth/src/parser/mod.rs b/sloth/src/parser/mod.rs
new file mode 100644
index 0000000..9d77acc
--- /dev/null
+++ b/sloth/src/parser/mod.rs
@@ -0,0 +1,57 @@
+pub mod ast;
+pub mod expr;
+pub mod stmt;
+
+use crate::lexer::{Token, TokenType};
+#[derive(Debug)]
+pub struct AstParser<'a> {
+    tokens: Vec<Token<'a>>,
+    index: usize,
+}
+
+/// Implementation containing utilities used by the parsers internal components
+impl<'a> AstParser<'a> {
+    pub fn new(tokens: Vec<Token<'a>>) -> Self {
+        Self { tokens, index: 0 }
+    }
+    pub fn peek(&self) -> &Token {
+        &self.tokens[self.index]
+    }
+
+    pub fn advance(&mut self) -> Option<&Token> {
+        if self.eof() {
+            return None;
+        }
+
+        self.index += 1;
+        Some(&self.tokens[self.index - 1])
+    }
+
+    pub fn advance_if(&mut self, next: impl FnOnce(&Token) -> bool) -> bool {
+        if self.eof() {
+            return false;
+        }
+
+        if next(self.peek()) {
+            self.advance();
+            return true;
+        }
+
+        false
+    }
+
+    pub fn advance_if_eq(&mut self, next: &TokenType) -> bool {
+        self.advance_if(|it| it.tt == *next)
+    }
+
+    pub fn consume(&mut self, next: TokenType, error: &str) {
+        if std::mem::discriminant(&self.peek().tt) != std::mem::discriminant(&next) {
+            panic!("{error} at index {:?}", self.index);
+        }
+        self.advance();
+    }
+
+    pub fn eof(&self) -> bool {
+        self.index >= self.tokens.len()
+    }
+}