parser beta

src/parser.rs

@@ -0,0 +1,79 @@
+// use std::collections::HashMap;
+use  crate::lexer::{Token, TokenType};
+use std::fmt;
+
+#[derive(Debug, Clone)]
+pub enum AstTypes {
+    FunctionDecleration
+}
+
+pub struct Ast {
+    pub type_: AstTypes,
+    pub values: Vec<Token>
+}
+
+impl<'a> fmt::Debug for Ast {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(f, "type={:?} values={:?}", self.type_, self.values)
+    }
+}
+
+#[derive(Debug, PartialEq, Clone, Copy)]
+pub enum AstDef {
+    Normal(TokenType),
+    Repeated(TokenType),
+    Optional(TokenType)
+}
+
+pub struct PNode {
+    ast_type: AstTypes,
+    ast_match: Vec<AstDef>
+}
+
+pub fn parse(tokens: &mut Vec<Token>) -> Box<Vec<Ast>> {
+    let ast_def: Vec<PNode> = vec![
+        PNode {
+            ast_type: AstTypes::FunctionDecleration,
+            ast_match: vec![AstDef::Normal(TokenType::Identifier), AstDef::Normal(TokenType::Identifier), AstDef::Normal(TokenType::Round), AstDef::Normal(TokenType::Curly)]
+        },
+        PNode {
+            ast_type: AstTypes::FunctionDecleration,
+            ast_match: vec![AstDef::Normal(TokenType::Keyword)]
+        },
+    ];
+    let tokens_len = tokens.len();
+    let mut ast: Vec<Ast> = Vec::new(); 
+    let mut current = 0;
+    let mut i = 0;
+    while tokens.len()>0 {
+        for ast_node in &ast_def {
+            if tokens_len < ast_node.ast_match.len() {
+                continue;
+            }
+            let mut ast_types: Vec<AstTypes> = vec![];
+            let mut is_match = false;
+            let mut matched: Vec<Token> = Vec::new();
+            for ast_match in &ast_node.ast_match {
+                match ast_match {
+                    AstDef::Normal(token_type) => {
+                        if &tokens[i].token_type == token_type {
+                            matched.push(tokens[i].clone());
+                            tokens.drain(0..1);
+                            is_match = true;
+                        } else {
+                            is_match = false;
+                        }
+                    }
+                    _ => {}
+                }
+            }
+            if is_match {
+                i = 0;
+                ast.push(Ast {values: matched, type_: ast_node.ast_type.clone()});
+                matched = Vec::new();
+                break;
+            }
+        }
+    }
+    Box::new(ast)
+}