From efaab433309170e8330a7722e90c26a93dbec252 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Edvard=20Th=C3=B6rnros?= <edvard.thornros@gmail.com>
Date: Sat, 9 Jan 2021 17:30:09 +0100
Subject: Start on compiler

---
 src/compiler.rs | 77 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 77 insertions(+)
 create mode 100644 src/compiler.rs

(limited to 'src/compiler.rs')

diff --git a/src/compiler.rs b/src/compiler.rs
new file mode 100644
index 0000000..59659f4
--- /dev/null
+++ b/src/compiler.rs
@@ -0,0 +1,77 @@
+use crate::tokenizer::{Token, TokenStream};
+use crate::vm::{Value, Block, Op};
+
+struct Compiler {
+    curr: usize,
+    tokens: TokenStream,
+}
+
+impl Compiler {
+    pub fn new(tokens: TokenStream) -> Self {
+        Self {
+            curr: 0,
+            tokens,
+        }
+    }
+
+    fn error(&self, msg: &str) -> ! {
+        println!("ERROR: {}", msg);
+        panic!();
+    }
+
+    fn peek(&self) -> Token {
+        if self.tokens.len() < self.curr {
+            crate::tokenizer::Token::EOF
+        } else {
+            self.tokens[self.curr].0.clone()
+        }
+    }
+
+    fn eat(&mut self) -> Token {
+        let t = self.peek();
+        self.curr += 1;
+        t
+    }
+
+    fn value(&mut self) -> Value {
+        match self.eat() {
+            Token::Float(f) => { Value::Float(f) },
+            Token::Int(f) => { Value::Int(f) }
+            _ => { self.error("Invalid value.") }
+        }
+    }
+
+    fn expression(&mut self, block: &mut Block) {
+        let a = self.value();
+        block.add(Op::Constant(a));
+
+        loop {
+            println!("{:?}", self.peek());
+            let op = match self.eat() {
+                Token::Plus => Op::Add,
+                Token::Minus => Op::Sub,
+                Token::Star => Op::Mul,
+                Token::Slash => Op::Div,
+                _ => { break; }
+            };
+
+            let b = self.value();
+            block.add(Op::Constant(b));
+            block.add(op);
+        }
+    }
+
+    pub fn compile(&mut self, name: &str) -> Block {
+        let mut block = Block::new(name);
+
+        self.expression(&mut block);
+        block.add(Op::Print);
+        block.add(Op::Return);
+
+        block
+    }
+}
+
+pub fn compile(name: &str, tokens: TokenStream) -> Block {
+    Compiler::new(tokens).compile(name)
+}
-- 
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