transition to l2

src/l2/l2_parser.lalrpop

@@ -0,0 +1,42 @@
+use l2::ast::*;
+
+use std::cell::Cell;
+
+grammar;
+
+pub TopLevel: TopLevel = {
+    "?-" <t:Term> "." => TopLevel::Query(t),
+    <r:Rule> "."      => TopLevel::Rule(r),
+    <t:Term> "."      => TopLevel::Fact(t),
+};
+
+Atom : Atom = {
+    r"[a-z][a-z0-9_]*" => <>.trim().to_string(),
+};
+
+BoxedTerm : Box<Term> = {
+    <t:Term> => Box::new(t),
+};
+
+Clause : Term = {
+    <a:Atom> "(" <ts: (<BoxedTerm> ",")*> <t:BoxedTerm> ")" => {
+     	let mut ts = ts;
+     	ts.push(t);
+	Term::Clause(Cell::new(RegType::Temp(0)), a, ts)
+    },
+};
+
+Rule : Rule = {
+    <c:Clause> ":-" <h:Term> <cs: ("," <Term>)*> =>
+         Rule { head: (c, h), clauses: cs },
+};
+
+Term : Term = {
+    <Clause> => <>,
+    <Atom> => Term::Atom(Cell::new(RegType::Temp(0)), <>),
+    <Var>  => Term::Var(Cell::new(VarReg::Norm(RegType::Temp(0))), <>),
+};
+
+Var : Var = {
+    r"[A-Z][a-z0-9_]*" => <>.trim().to_string(),
+};