Change the way blocks are handled, i.e. not expressions but something else

src/emitter.rs

@@ -42,7 +42,7 @@ pub fn emit_all(w: &mut dyn Write, ast: &Vec<parser::Stmt>, ctx: &mut LexicalCon
 
 pub fn emit(w: &mut dyn Write, stmt: &parser::Stmt, ctx: &mut LexicalContext) -> std::io::Result<()> {
     match &stmt {
-	parser::Stmt::ReplPrint(expr) => {
+	parser::Stmt::BareExpr(expr) => {
 	    write!(w, "console.log((")?;
 	    emit_expr(w, expr, ctx)?;
 	    writeln!(w, "));")?;
@@ -72,13 +72,13 @@ pub fn emit(w: &mut dyn Write, stmt: &parser::Stmt, ctx: &mut LexicalContext) ->
 		emit_expr(w, &if_block.guard, ctx)?;
 		writeln!(w, ") {{")?;
 		let mut block_ctx = LexicalContext::new(ctx);
-		emit_expr(w, &if_block.block, &mut block_ctx)?;
+		emit_all(w, &if_block.block, &mut block_ctx)?;
 		writeln!(w, "}}")?;
 	    }
 	    if let Some(block) = else_block {
 		writeln!(w, "else {{")?;
 		let mut block_ctx = LexicalContext::new(ctx);
-		emit_expr(w, block, &mut block_ctx)?;
+		emit_all(w, block, &mut block_ctx)?;
 		writeln!(w, "}}")?;
 	    }
 	}
@@ -113,18 +113,9 @@ pub fn emit_expr(w: &mut dyn Write, expr: &parser::Expr, ctx: &mut LexicalContex
 	    }
 	    let mut fun_ctx = LexicalContext::new(ctx);
 	    fun_ctx.is_tail = true;
-	    emit_expr(w, body.as_ref(), &mut fun_ctx)?;
+	    emit_all(w, body.as_ref(), &mut fun_ctx)?;
 	    write!(w, "}}")?;
 	}
-	parser::Expr::Block(stmts) => {
-	    let mut peek_iter = stmts.iter().peekable();
-	    while let Some(stmt) = peek_iter.next() {
-		if peek_iter.peek().is_none() {
-		    write!(w, "return ")?;
-		}
-		emit(w, stmt, ctx)?;
-	    }
-	}   
 	parser::Expr::Plus(e1, e2) => {
 	    emit_expr(w, e1.as_ref(), ctx)?;
 	    write!(w, " + ")?;

src/evaluator.rs

@@ -38,7 +38,7 @@ impl<'a> Env<'a> {
 
 pub fn eval(ast: &parser::Stmt, env: &mut Env) {
     match &ast {
-        parser::Stmt::ReplPrint(expr) =>
+        parser::Stmt::BareExpr(expr) =>
             println!("{}", eval_expr(expr, env)),
         parser::Stmt::Assignment(id, expr) =>
             env.set(id.clone(), eval_expr(expr, env)),
@@ -49,11 +49,9 @@ pub fn eval(ast: &parser::Stmt, env: &mut Env) {
                 match res {
                     Atom::Bool(true) => {
                         matched = true;
-			if let parser::Expr::Block(block) = block {
+                        for stmt in block {
-                            for stmt in block {
+			    eval(stmt, env);
-				eval(stmt, env);
+                        }
-                            }
-			}
                         break;
                     }
                     Atom::Bool(false) => continue,
@@ -62,7 +60,9 @@ pub fn eval(ast: &parser::Stmt, env: &mut Env) {
             }
             if !matched {
                 if let Some(block) = default_block {
-                    eval_expr(block, env);
+		    for stmt in block {
+			eval(stmt, env);
+		    }
                 }
             }
         }

src/parser.rs

@@ -4,8 +4,8 @@ use std::fmt;
 pub enum Stmt {
     Assignment(String, Expr),
     Funcall(Expr),
-    Conditional(Vec<GuardedBlock>, Option<Expr>),
+    Conditional(Vec<GuardedBlock>, Option<Block>),
-    ReplPrint(Expr),
+    BareExpr(Expr),
 }
 
 #[derive(Debug,PartialEq,Clone)]
@@ -13,15 +13,16 @@ pub enum Expr {
     Id(String),
     Atom(Atom),
     Funcall(String, Vec<Expr>),
-    Funcdef(Option<String>, Box<Expr>),
+    Funcdef(Option<String>, Block),
     UnaryMinus(Box<Expr>),
     Plus(Box<Expr>, Box<Expr>),
     Minus(Box<Expr>, Box<Expr>),
     Mult(Box<Expr>, Box<Expr>),
     Div(Box<Expr>, Box<Expr>),
-    Block(Vec<Stmt>),
 }
 
+pub type Block = Vec<Stmt>;
+
 #[derive(Debug,PartialEq,Clone)]
 pub enum Atom {
     String(String),
@@ -42,7 +43,7 @@ impl fmt::Display for Atom {
 #[derive(Debug,PartialEq,Clone)]
 pub struct GuardedBlock {
     pub guard: Expr,
-    pub block: Expr,
+    pub block: Block,
 }
 
 peg::parser! {
@@ -53,7 +54,7 @@ peg::parser! {
             = a:assignment() { a } /
             f:funcall() stop() { Stmt::Funcall(f) } /
             c:conditional() { c } /
-            e:expr() stop() { Stmt::ReplPrint(e) }
+            e:expr() stop() { Stmt::BareExpr(e) }
         rule expr() -> Expr = precedence! {
             "-" _ e1:@ { Expr::UnaryMinus(Box::new(e1)) }
             --
@@ -84,7 +85,7 @@ peg::parser! {
         rule funcall() -> Expr
             = i:id() "(" _ e:(expr() ** ("," _)) ")" _ { Expr::Funcall(i, e) }
         rule funcdef() -> Expr
-            = i:id()? "->" _ e:(expr() / block()) { Expr::Funcdef(i, Box::new(e)) }
+            = i:id()? "->" _ b:(block()) { Expr::Funcdef(i, b) }
         rule conditional() -> Stmt
             = i:_if() __* ei:elif()* __* e:_else()? __* { Stmt::Conditional([vec![i], ei].concat(), e) }
         rule _if() -> GuardedBlock
@@ -101,11 +102,12 @@ peg::parser! {
                     block: b
                 }
             }
-        rule _else() -> Expr
+        rule _else() -> Block
             = "else" _ b:block() { b }
-        rule block() -> Expr
+        rule block() -> Block
-            = i:indented_block() { Expr::Block(i) }
+            = i:indented_block() { i } /
-        rule indented_block() -> Vec<Stmt>
+	    e:expr() { vec![Stmt::BareExpr(e)] }
+        rule indented_block() -> Block
             = stop() indent() __* s:stmt()+ dedent() { s }
 
         rule letter()
@@ -280,36 +282,36 @@ foo <- x -> y -> x * y";
                 "foo".to_string(),
                 Expr::Funcdef(
                     None,
-                    Box::new(Expr::Funcall("bar".to_string(), vec![])),
+                    vec![Stmt::BareExpr(Expr::Funcall("bar".to_string(), vec![]))],
-                )
+                ),
             ),
             Stmt::Assignment(
                 "foo".to_string(),
                 Expr::Funcdef(
                     None,
-                    Box::new(Expr::Block(vec![
+		    vec![
                         Stmt::Funcall(Expr::Funcall("bar".to_string(), vec![])),
                         Stmt::Funcall(Expr::Funcall("baz".to_string(), vec![])),
-                    ]))
+                    ],
-                )
+		)
             ),
             Stmt::Assignment(
                 "foo".to_string(),
                 Expr::Funcdef(
                     Some("x".to_string()),
-                    Box::new(
+                    vec![
-                        Expr::Funcdef(
+                        Stmt::BareExpr(Expr::Funcdef(
                             Some("y".to_string()),
-                            Box::new(
+			    vec![
-                                Expr::Mult(
+                                Stmt::BareExpr(Expr::Mult(
                                     Box::new(Expr::Id("x".to_string())),
                                     Box::new(Expr::Id("y".to_string())),
-                                )
+                                ))
-                            )
+                            ],
-                        )
+                        ))
-                    )
+                    ],
                 )
-            )
+            ),
         ];
         assert_eq!(deelang_parser::program(prgm).unwrap(), expected);
     }
@@ -328,14 +330,14 @@ else
             vec![
                 GuardedBlock {
                     guard: Expr::Id("foo".to_string()),
-                    block: Expr::Block(vec![Stmt::Funcall(Expr::Funcall("bar".to_string(), vec![]))])
+                    block: vec![Stmt::Funcall(Expr::Funcall("bar".to_string(), vec![]))]
                 },
                 GuardedBlock {
                     guard: Expr::Id("baz".to_string()),
-                    block: Expr::Block(vec![Stmt::Funcall(Expr::Funcall("foobar".to_string(), vec![]))])
+                    block: vec![Stmt::Funcall(Expr::Funcall("foobar".to_string(), vec![]))],
                 },
             ],
-            Some(Expr::Block(vec![Stmt::Funcall(Expr::Funcall("quux".to_string(), vec![]))])),
+            Some(vec![Stmt::Funcall(Expr::Funcall("quux".to_string(), vec![]))]),
         )];
         assert_eq!(deelang_parser::program(prgm).unwrap(), expected);
     }