Add an explicit 'print' command (#4535)

crates/nu-cli/src/util.rs

@@ -0,0 +1,73 @@
+use std::io::Write;
+
+use nu_protocol::{
+    ast::Call,
+    engine::{EngineState, Stack},
+    PipelineData, ShellError, Span, Value,
+};
+
+pub fn print_pipeline_data(
+    input: PipelineData,
+    engine_state: &EngineState,
+    stack: &mut Stack,
+) -> Result<(), ShellError> {
+    // If the table function is in the declarations, then we can use it
+    // to create the table value that will be printed in the terminal
+
+    let config = stack.get_config().unwrap_or_default();
+
+    let stdout = std::io::stdout();
+
+    if let PipelineData::RawStream(stream, _, _) = input {
+        for s in stream {
+            let _ = stdout.lock().write_all(s?.as_binary()?);
+        }
+        return Ok(());
+    }
+
+    match engine_state.find_decl("table".as_bytes()) {
+        Some(decl_id) => {
+            let table = engine_state.get_decl(decl_id).run(
+                engine_state,
+                stack,
+                &Call::new(Span::new(0, 0)),
+                input,
+            )?;
+
+            for item in table {
+                let stdout = std::io::stdout();
+
+                if let Value::Error { error } = item {
+                    return Err(error);
+                }
+
+                let mut out = item.into_string("\n", &config);
+                out.push('\n');
+
+                match stdout.lock().write_all(out.as_bytes()) {
+                    Ok(_) => (),
+                    Err(err) => eprintln!("{}", err),
+                };
+            }
+        }
+        None => {
+            for item in input {
+                let stdout = std::io::stdout();
+
+                if let Value::Error { error } = item {
+                    return Err(error);
+                }
+
+                let mut out = item.into_string("\n", &config);
+                out.push('\n');
+
+                match stdout.lock().write_all(out.as_bytes()) {
+                    Ok(_) => (),
+                    Err(err) => eprintln!("{}", err),
+                };
+            }
+        }
+    };
+
+    Ok(())
+}