add tengri_core; fix errors and warnings; unify deps

dsl/src/dsl_provide.rs

@@ -0,0 +1,44 @@
+use crate::*;
+
+/// Map EDN tokens to parameters of a given type for a given context
+pub trait Dsl<U>: Sized {
+    fn take <'state, 'source> (_: &'state Self, _: &mut TokenIter<'source>) -> Perhaps<U> {
+        Ok(None)
+    }
+}
+
+/// Map EDN tokens to parameters of a given type for a given context
+pub trait Context<'state, U>: Sized {
+    fn get <'source> (&'state self, _iter: &mut TokenIter<'source>) -> Option<U> {
+        None
+    }
+}
+
+impl<'state, T: Context<'state, U>, U> Context<'state, U> for &T {
+    fn get <'source> (&'state self, iter: &mut TokenIter<'source>) -> Option<U> {
+        (*self).get(iter)
+    }
+}
+
+impl<'state, T: Context<'state, U>, U> Context<'state, U> for Option<T> {
+    fn get <'source> (&'state self, iter: &mut TokenIter<'source>) -> Option<U> {
+        self.as_ref().map(|s|s.get(iter)).flatten()
+    }
+}
+
+pub trait TryFromDsl<'state, T>: Sized {
+    fn try_from_expr <'source: 'state> (
+        _state: &'state T, _iter: &mut TokenIter<'source>
+    ) -> Option<Self> {
+        None
+    }
+    fn try_from_atom <'source: 'state> (
+        state: &'state T, value: Value<'source>
+    ) -> Option<Self> {
+        if let Exp(0, mut iter) = value {
+            return Self::try_from_expr(state, &mut iter)
+        }
+        None
+    }
+}
+