Internals cleanup and | select ...fields

src/commands/select.rs

@@ -0,0 +1,46 @@
+use crate::errors::ShellError;
+use crate::object::base::select;
+use crate::object::process::Process;
+use crate::object::{DirEntry, ShellObject, Value};
+use crate::prelude::*;
+use crate::Args;
+use derive_new::new;
+use std::path::{Path, PathBuf};
+use sysinfo::SystemExt;
+
+#[derive(new)]
+pub struct SelectBlueprint;
+
+impl crate::CommandBlueprint for SelectBlueprint {
+    fn create(
+        &self,
+        args: Vec<Value>,
+        host: &dyn Host,
+        env: &mut Environment,
+    ) -> Result<Box<dyn Command>, ShellError> {
+        if args.is_empty() {
+            return Err(ShellError::string("take requires an integer"));
+        }
+
+        let fields: Result<_, _> = args.iter().map(|a| a.as_string()).collect();
+
+        Ok(Box::new(Select { fields: fields? }))
+    }
+}
+
+#[derive(new)]
+pub struct Select {
+    fields: Vec<String>,
+}
+
+impl crate::Command for Select {
+    fn run(&mut self, stream: VecDeque<Value>) -> Result<VecDeque<ReturnValue>, ShellError> {
+        let objects = stream
+            .iter()
+            .map(|item| Value::Object(Box::new(select(item, &self.fields))))
+            .map(|item| ReturnValue::Value(item))
+            .collect();
+
+        Ok(objects)
+    }
+}