Initial commit.

src/l0/l0_parser.lalrpop

@@ -0,0 +1,30 @@
+use l0::ast::{Atom, Term, TopLevel, Var};
+
+grammar;
+
+pub TopLevel: TopLevel = {
+    "?-" <t:Term> "." => TopLevel::Query(t),
+    <t:Term> "."      => TopLevel::Fact(t),
+};
+
+Atom : Atom = {
+     r"[a-z][a-z0-9_]*" => <>.trim().to_string(),
+};
+
+Var : Var = {
+     r"[A-Z][a-z0-9_]*" => <>.trim().to_string(),
+};	
+
+BoxedTerm : Box<Term> = {
+     <t:Term> => Box::new(t),
+};
+
+Term : Term = {
+     <a:Atom> "(" <ts: (<BoxedTerm> ",")*> <t:BoxedTerm> ")" => {
+     	      let mut ts = ts;
+     	      ts.push(t);
+	      Term::Clause(a, ts)
+     },
+     <Atom> => Term::Atom(<>),
+     <Var>  => Term::Var(<>),
+};