Indentation and funcdefs

rust/src/parser.rs

@@ -9,13 +9,19 @@ pub enum Expr<'a> {
     Id(&'a str),
     Num(f64),
     Funcall(&'a str, Vec<Expr<'a>>),
-    Funcdef(Option<&'a str>, Vec<Stmt<'a>>),
+    Funcdef(Option<&'a str>, Fun<'a>),
     Plus(Box<Expr<'a>>, Box<Expr<'a>>),
     Minus(Box<Expr<'a>>, Box<Expr<'a>>),
     Mult(Box<Expr<'a>>, Box<Expr<'a>>),
     Div(Box<Expr<'a>>, Box<Expr<'a>>),
 }
 
+#[derive(Debug,PartialEq)]
+pub enum Fun<'a> {
+    Oner(Box<Expr<'a>>),
+    Block(Vec<Stmt<'a>>),
+}
+
 peg::parser! {
     grammar deelang_parser() for str {
         pub rule program() -> Vec<Stmt<'input>>
@@ -31,8 +37,8 @@ peg::parser! {
             e1:(@) "/" _ e2:@ { Expr::Div(Box::new(e1), Box::new(e2)) }
             --
             "(" _ e:expr() ")" _ { e }
-            f:funcall() _ { f }
-            i:id()? "->" _ s:stmt() { Expr::Funcdef(i, vec![s]) }
+            f:funcall() { f }
+            f:funcdef() { f } 
             i:id() _ { Expr::Id(i) }
             n:num() _ { Expr::Num(n) }
         }
@@ -43,6 +49,9 @@ peg::parser! {
             = n:$(digit()+ "."? digit()* / "." digit()+) _ { n.parse().unwrap() }
         rule funcall() -> Expr<'input>
             = i:id() "(" _ e:(expr() ** ("," _)) ")" _ { Expr::Funcall(i, e) }
+        rule funcdef() -> Expr<'input>
+            = i:id()? "->" _ e:expr() { Expr::Funcdef(i, Fun::Oner(Box::new(e))) } /
+              i:id()? "->" _ stop() indent() __* s:stmt()+ dedent() { Expr::Funcdef(i, Fun::Block(s)) }
 
         rule letter()
             = ['A'..='Z'] / ['a'..='z']
@@ -50,6 +59,10 @@ peg::parser! {
             = ['0'..='9']
         rule stop()
             = __+ / eof()
+        rule indent()
+            = ">>>"
+        rule dedent()
+            = "<<<"
         rule _ // Non-meaningful whitespace
             = ['\t'|' ']*
         rule __ // End Of Statement (comment, newline, eof, TODO semicolon)
@@ -155,14 +168,52 @@ four <- (3 - 1) * 2";
     #[test]
     fn test_funcdef() {
         let prgm = r"foo <- -> bar()
-";
+foo <- ->
+>>>
+bar()
+baz()
+<<<
+foo <- x -> y -> x * y";
         let expected = vec![
-            Stmt::Assignment("foo",
-                             Expr::Funcdef(
-                                 None,
-                                 vec![
-                                     Stmt::Funcall(Expr::Funcall("bar", vec![])),
-                                 ])
+            Stmt::Assignment(
+                "foo",
+                Expr::Funcdef(
+                    None,
+                    Fun::Oner(
+                        Box::new(Expr::Funcall("bar", vec![])),
+                    )
+                )
+            ),
+            Stmt::Assignment(
+                "foo",
+                Expr::Funcdef(
+                    None,
+                    Fun::Block(vec![
+                        Stmt::Funcall(Expr::Funcall("bar", vec![])),
+                        Stmt::Funcall(Expr::Funcall("baz", vec![])),
+                    ])
+                )
+            ),
+            Stmt::Assignment(
+                "foo",
+                Expr::Funcdef(
+                    Some("x"),
+                    Fun::Oner(
+                        Box::new(
+                            Expr::Funcdef(
+                                Some("y"),
+                                Fun::Oner(
+                                    Box::new(
+                                        Expr::Mult(
+                                            Box::new(Expr::Id("x")),
+                                            Box::new(Expr::Id("y")),
+                                        )
+                                    )
+                                )
+                            )
+                        )
+                    )
+                )
             )
         ];