Add wrap and get and cell_path parsing

crates/nu-protocol/src/ast/call.rs

@@ -45,4 +45,8 @@ impl Call {
 
         None
     }
+
+    pub fn nth(&self, pos: usize) -> Option<Expression> {
+        self.positional.get(pos).cloned()
+    }
 }

crates/nu-protocol/src/ast/cell_path.rs

@@ -1,13 +1,14 @@
 use super::Expression;
 use crate::Span;
+use serde::{Deserialize, Serialize};
 
-#[derive(Debug, Clone)]
+#[derive(Debug, Clone, Serialize, Deserialize)]
 pub enum PathMember {
     String { val: String, span: Span },
     Int { val: usize, span: Span },
 }
 
-#[derive(Debug, Clone)]
+#[derive(Debug, Clone, Serialize, Deserialize)]
 pub struct CellPath {
     pub members: Vec<PathMember>,
 }

crates/nu-protocol/src/ast/expr.rs

@@ -1,4 +1,4 @@
-use super::{Call, Expression, FullCellPath, Operator, RangeOperator};
+use super::{Call, CellPath, Expression, FullCellPath, Operator, RangeOperator};
 use crate::{BlockId, Signature, Span, VarId};
 
 #[derive(Debug, Clone)]
@@ -24,6 +24,7 @@ pub enum Expr {
     Table(Vec<Expression>, Vec<Vec<Expression>>),
     Keyword(Vec<u8>, Span, Box<Expression>),
     String(String), // FIXME: improve this in the future?
+    CellPath(CellPath),
     FullCellPath(Box<FullCellPath>),
     Signature(Box<Signature>),
     Garbage,