Working on policy DSL

src/delegation.rs

@@ -13,6 +13,7 @@
 //! - [`store`] is an interface for caching [`Delegation`]s.
 
 pub mod condition;
+pub mod policy;
 pub mod store;
 
 mod agent;

src/delegation/condition.rs

@@ -27,6 +27,7 @@ pub use traits::Condition;
 use crate::ability::arguments;
 use libipld_core::{error::SerdeError, ipld::Ipld, serde as ipld_serde};
 use serde_derive::{Deserialize, Serialize};
+use std::collections::BTreeMap;
 
 /// The union of the common [`Condition`]s that ship directly with this library.
 #[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]

src/delegation/policy.rs

@@ -0,0 +1,2 @@
+pub mod frontend;
+pub mod ir;

src/delegation/policy/frontend.rs

@@ -0,0 +1,62 @@
+use super::ir;
+use libipld_core::ipld::Ipld;
+use serde::{Deserialize, Serialize};
+use std::collections::BTreeMap;
+
+#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
+pub enum Term {
+    // Leaves
+    Args, // $
+    Literal(Ipld),
+    Variable(Variable),
+
+    Selector(Selector),
+
+    // Connectives
+    Not(Box<Term>),
+    And(Vec<Term>),
+    Or(Vec<Term>),
+
+    // Comparison
+    Equal(Value, Value),
+    GreaterThan(Value, Value),
+    GreaterOrEqual(Value, Value),
+    LessThan(Value, Value),
+    LessOrEqual(Value, Value),
+
+    // String Matcher
+    Glob(Value, String),
+
+    // Existential Quantification
+    Exists(Variable, Collection), // ∃x ∈ xs
+}
+
+#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
+pub struct Variable(String); // ?x
+
+#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
+pub enum Collection {
+    Array(Vec<Ipld>),
+    Map(BTreeMap<String, Ipld>),
+    Variable(Variable),
+    Selector(Selector),
+}
+
+#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
+pub struct Selector(Vec<Index>); // .foo.bar[].baz
+
+#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
+pub enum Index {
+    This,
+    // RecDesend,    // ..
+    FlattenAll,   // .[]
+    Index(usize), // .[2]
+    Key(String),  // .key
+}
+
+#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
+pub enum Value {
+    Literal(Ipld),
+    Variable(Variable),
+    ImplicitBind(Selector),
+}