From a1a046f9dde731e6e3d0ffe825ad01aeb1c9e70e Mon Sep 17 00:00:00 2001
From: Johannes Stoelp <johannes.stoelp@gmail.com>
Date: Fri, 3 Sep 2021 00:06:38 +0200
Subject: ch2: added parser following chapter 2

---
 src/main.rs | 66 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 61 insertions(+), 5 deletions(-)

(limited to 'src/main.rs')

diff --git a/src/main.rs b/src/main.rs
index 361f76f..0e91734 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,18 +1,74 @@
 mod lexer;
+mod parser;
 
-use lexer::Lexer;
+use lexer::{Lexer, Token};
+use parser::Parser;
 use std::io::Read;
 
+fn handle_definition<I>(p: &mut Parser<I>)
+where
+    I: Iterator<Item = char>,
+{
+    match p.parse_definition() {
+        Ok(expr) => println!("Parse 'def'\n{:?}", expr),
+        Err(err) => {
+            eprintln!("Error: {:?}", err);
+            p.get_next_token();
+        }
+    }
+}
+
+fn handle_extern<I>(p: &mut Parser<I>)
+where
+    I: Iterator<Item = char>,
+{
+    match p.parse_extern() {
+        Ok(expr) => println!("Parse 'extern'\n{:?}", expr),
+        Err(err) => {
+            eprintln!("Error: {:?}", err);
+            p.get_next_token();
+        }
+    }
+}
+
+fn handle_top_level_expression<I>(p: &mut Parser<I>)
+where
+    I: Iterator<Item = char>,
+{
+    match p.parse_top_level_expr() {
+        Ok(expr) => println!("Parse top-level expression\n{:?}", expr),
+        Err(err) => {
+            eprintln!("Error: {:?}", err);
+            p.get_next_token();
+        }
+    }
+}
+
 fn main() {
-    println!("Lex stdin.");
-    println!("ENTER to lex current input.");
+    println!("Parse stdin.");
+    println!("ENTER to parse current input.");
     println!("C-c   to exit.");
-    let mut lex = Lexer::new(std::io::stdin().bytes().filter_map(|v| {
+
+    let lexer = Lexer::new(std::io::stdin().bytes().filter_map(|v| {
         let v = v.ok()?;
         Some(v.into())
     }));
 
+    let mut parser = Parser::new(lexer);
+
+    // Throw first coin and initialize cur_tok.
+    parser.get_next_token();
+
     loop {
-        println!("{:?}", lex.gettok());
+        match *parser.cur_tok() {
+            Token::Eof => break,
+            Token::Char(';') => {
+                // Ignore top-level semicolon.
+                parser.get_next_token()
+            }
+            Token::Def => handle_definition(&mut parser),
+            Token::Extern => handle_extern(&mut parser),
+            _ => handle_top_level_expression(&mut parser),
+        }
     }
 }
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