Prepare optimizer

Cargo.lock

@@ -76,6 +76,7 @@ name = "entry"
 version = "0.1.0"
 dependencies = [
  "compiler",
+ "lower",
  "parser",
  "vm",
 ]

compiler/src/lib.rs

@@ -157,9 +157,9 @@ impl Compiler {
         }
     }
 
-    pub fn compile_program(&mut self, stmts: Vec<(Stmt, Span)>) -> Vec<Instr> {
+    pub fn compile_program(&mut self, stmts: Vec<Stmt>) -> Vec<Instr> {
         let mut instrs = vec![];
-        for (stmt, _) in stmts {
+        for stmt in stmts {
             instrs.extend(self.compile_stmt(stmt));
         }
         instrs

entry/Cargo.toml

@@ -5,6 +5,7 @@ edition = "2021"
 
 [dependencies]
 parser = { path = "../parser" }
+lower = { path = "../lower" }
 compiler = { path = "../compiler" }
 vm = { path = "../vm" }
 

entry/src/main.rs

@@ -1,4 +1,5 @@
 use compiler::Compiler;
+use lower::Lower;
 use parser::{lex, parse, report};
 use vm::exec::Executor;
 
@@ -11,8 +12,10 @@ fn main() {
         let (ast, parse_errors) = parse(tokens, src.len());
 
         if let Some(ast) = ast {
+            let mut lower = Lower::new();
+            let last = lower.opt_stmts(ast.iter().map(|(s, _)| s.clone()).collect());
             let mut compiler = Compiler::new();
-            let instrs = compiler.compile_program(ast);
+            let instrs = compiler.compile_program(last);
             // instrs.iter().for_each(|i| println!("{:?}", i));
             let mut executor = Executor::new(instrs);
             match executor.run() {

examples/a.hlm

@@ -8,6 +8,5 @@ end
 fun double x = x * 2
 
 fun main = do
-    let add = \x y -> x + y in
-        print(add(double(17), succ(34)))
+    x |> \a -> println(a)
 end

examples/ht.hlm

@@ -1,12 +1,15 @@
+// This is just proof of concept on what the language
+// might look like in the future
+
 import http from "http"
 
--- Define a custom type to represent a user
+// Define a custom type to represent a user
 type User =
     id: number,
     name: string,
 end
 
--- Define a function to handle incoming HTTP requests
+// Define a function to handle incoming HTTP requests
 fun handle_request
     req: http.IncomingMessage,
     res: http.ServerResponse,

lower/src/lib.rs

@@ -1,6 +1,8 @@
 #![allow(clippy::new_without_default)]
 use parser::*;
 
+type SExpr = (Expr, std::ops::Range<usize>);
+
 pub struct Lower {}
 
 impl Lower {
@@ -8,13 +10,39 @@ impl Lower {
         Self {}
     }
 
-    fn fold_pipe(&self, e: Expr) -> Vec<Expr> {
-        if let Expr::Binary((BinaryOp::Pipe, _), left, right) = e {
-            vec![Expr::Call(right, vec![*left])]
-        } else {
-            unreachable!()
+    pub fn opt_stmts(&self, ss: Vec<Stmt>) -> Vec<Stmt> {
+        ss.into_iter()
+            .flat_map(|s| self.opt_stmt(s.clone()).unwrap_or_else(|| vec![s]))
+            .collect()
+    }
+
+    pub fn opt_stmt(&self, s: Stmt) -> Option<Vec<Stmt>> {
+        match s {
+            // Stmt::Fun(name, args, body) => Some(vec![Stmt::Fun(
+            //     name,
+            //     args,
+            //     self.opt_expr(body.0).unwrap_or_else(|| vec![body.0]),
+            // )]),
+            _ => None,
         }
     }
+
+    pub fn opt_exprs(&self, es: Vec<Expr>) -> Vec<Expr> {
+        es.into_iter()
+            .flat_map(|e| self.opt_expr(e.clone()).unwrap_or_else(|| vec![e]))
+            .collect()
+    }
+
+    pub fn opt_expr(&self, e: Expr) -> Option<Vec<Expr>> {
+        match e {
+            Expr::Binary((BinaryOp::Pipe, _), left, right) => Some(self.fold_pipe(*left, *right)),
+            _ => None,
+        }
+    }
+
+    fn fold_pipe(&self, left: SExpr, right: SExpr) -> Vec<Expr> {
+        vec![Expr::Call(Box::new(right), vec![left])]
+    }
 }
 
 #[cfg(test)]
@@ -35,7 +63,7 @@ mod test {
 
         let ex = ex.unwrap();
         let l = Lower::new();
-        let ex = l.fold_pipe(ex.0);
+        let ex = l.opt_expr(ex.0).unwrap();
         println!("{:?}", ex);
     }
 }