Add select command which opens cell

src/cli.rs

@@ -54,6 +54,7 @@ pub async fn cli() -> Result<(), Box<Error>> {
             command("column", column::column),
             command("split", split::split),
             command("reject", reject::reject),
+            command("select", select::select),
             command("to-array", to_array::to_array),
             command("to-json", to_json::to_json),
             Arc::new(Where),

src/commands.rs

@@ -8,6 +8,7 @@ crate mod ls;
 crate mod open;
 crate mod ps;
 crate mod reject;
+crate mod select;
 crate mod size;
 crate mod skip;
 crate mod sort_by;

src/commands/select.rs

@@ -0,0 +1,36 @@
+use crate::errors::ShellError;
+use crate::object::Value;
+use crate::object::base::select_fields;
+use crate::prelude::*;
+
+pub fn select(args: CommandArgs) -> Result<OutputStream, ShellError> {
+    if args.args.is_empty() {
+        return Err(ShellError::string("select requires a field"));
+    }
+
+    let fields: Result<Vec<String>, _> = args.args.iter().map(|a| a.as_string()).collect();
+    let fields = fields?;
+
+    let stream = args
+        .input
+        .map(move |item| {
+            let mut result = VecDeque::new();
+            let column = select_fields(&item, &fields);
+            for field in &fields {
+                match column.get_data_by_key(&field) {
+                    Some(Value::List(l)) => {
+                        for item in l {
+                            result.push_back(ReturnValue::Value(item.copy()));
+                        }
+                    }
+                    Some(x) => result.push_back(ReturnValue::Value(x.copy())),
+                    None => {}
+                }
+            }
+
+            result
+        })
+        .flatten();
+
+    Ok(stream.boxed())
+}

src/evaluate/evaluator.rs

@@ -17,7 +17,6 @@ impl Scope {
 
 crate fn evaluate_expr(expr: &ast::Expression, scope: &Scope) -> Result<Value, ShellError> {
     use ast::*;
-
     match expr {
         Expression::Leaf(l) => Ok(evaluate_leaf(l)),
         Expression::Parenthesized(p) => evaluate_expr(&p.expr, scope),