More trying out peg

Cargo.lock

@@ -558,6 +558,33 @@ dependencies = [
  "winapi 0.3.8",
 ]
 
+[[package]]
+name = "peg"
+version = "0.7.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "07c0b841ea54f523f7aa556956fbd293bcbe06f2e67d2eb732b7278aaf1d166a"
+dependencies = [
+ "peg-macros",
+ "peg-runtime",
+]
+
+[[package]]
+name = "peg-macros"
+version = "0.7.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b5aa52829b8decbef693af90202711348ab001456803ba2a98eb4ec8fb70844c"
+dependencies = [
+ "peg-runtime",
+ "proc-macro2 1.0.30",
+ "quote 1.0.10",
+]
+
+[[package]]
+name = "peg-runtime"
+version = "0.7.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c719dcf55f09a3a7e764c6649ab594c18a177e3599c467983cdf644bfc0a4088"
+
 [[package]]
 name = "phf"
 version = "0.7.24"
@@ -895,6 +922,7 @@ dependencies = [
  "ena",
  "failure",
  "itertools",
+ "peg",
  "pretty_assertions",
  "radix_trie",
  "schala-lang-codegen",

schala-lang/language/src/parsing/new.rs

@@ -1,8 +1,72 @@
 use crate::ast::*;
 
 peg::parser! {
-    grammar yolo() for str {
+    grammar schala_parser() for str {
-        rule number() ->
+
+        pub rule program() -> AST =
+            n:(statement() ** delimiter() ) { AST { id: Default::default(), statements: n.into() } }
+
+        rule delimiter() = ";" / "\n"
+
+        rule statement() -> Statement =
+            expr:expression() { Statement {
+                id: Default::default(), location: Default::default(), kind: StatementKind::Expression(expr) }
+            }
+
+        pub rule expression() -> Expression =
+            kind:expression_kind() { Expression { id: Default::default(), type_anno: None, kind: kind } }
+
+        rule expression_kind() -> ExpressionKind =
+            primary()
+
+        rule primary() -> ExpressionKind =
+           float_literal() / nat_literal()
+
+        rule nat_literal() -> ExpressionKind =
+            ("0x" / "0b")? digits:digits() { ExpressionKind::NatLiteral(digits.parse().unwrap()) }
+
+        rule float_literal() -> ExpressionKind =
+            ds:$( digits() "." digits()? / "." digits() ) { ExpressionKind::FloatLiteral(ds.parse().unwrap()) }
+
+        rule digits() -> &'input str =
+            $((digit_group() "_"*)+)
+
+        rule digit_group() -> &'input str = $(['0'..='9']+)
 
     }
 }
+
+#[cfg(test)]
+mod test {
+    use super::*;
+
+    #[test]
+    fn new_parser() {
+        let parsed = schala_parser::expression("4");
+        assert_eq!(parsed.unwrap(), Expression { id: Default::default(), type_anno: None, kind: ExpressionKind::NatLiteral(4) });
+
+        let parsed = schala_parser::program("56.1");
+        if let Err(ref err) = parsed {
+            println!("{}", err);
+        }
+        assert_eq!(parsed.unwrap(), AST {
+            id: Default::default(), statements: vec![
+                Statement {
+                    id: Default::default(),
+                    location: Default::default(),
+                    kind: StatementKind::Expression(Expression { id: Default::default(), type_anno: None, kind:
+                        ExpressionKind::FloatLiteral(56.1) })
+                }
+
+            ].into() });
+
+        /*
+        let parsed = schala_parser::expression("quincy");
+        println!("{:?}", parsed.unwrap_err());
+
+        assert_eq!(1, 2);
+        */
+
+    }
+
+}