Add the missing print command

src/commands.rs

@@ -0,0 +1,79 @@
+/// Copy of the nushell print command with a slight adjustment for pipelines
+/// Source: https://github.com/nushell/nushell/blob/98525043edd20abb62da09726d75816d09d68f1e/crates/nu-cli/src/print.rs
+use nu_engine::CallExt;
+use nu_protocol::ast::Call;
+use nu_protocol::engine::{Command, EngineState, Stack};
+use nu_protocol::{
+    Category, IntoPipelineData, PipelineData, ShellError, Signature, Span, SyntaxShape, Type, Value,
+};
+
+use crate::NewEmpty;
+
+#[derive(Clone)]
+pub struct PrintCommand;
+
+impl Command for PrintCommand {
+    fn name(&self) -> &str {
+        "print"
+    }
+
+    fn signature(&self) -> Signature {
+        Signature::build("print")
+            .input_output_types(vec![
+                (Type::Nothing, Type::Nothing),
+                (Type::Any, Type::Nothing),
+            ])
+            .allow_variants_without_examples(true)
+            .rest("rest", SyntaxShape::Any, "the values to print")
+            .switch(
+                "no-newline",
+                "print without inserting a newline for the line ending",
+                Some('n'),
+            )
+            .switch("stderr", "print to stderr instead of stdout", Some('e'))
+            .category(Category::Strings)
+    }
+
+    fn usage(&self) -> &str {
+        "Print the given values to stdout."
+    }
+
+    fn extra_usage(&self) -> &str {
+        r#"Unlike `echo`, this command does not return any value (`print | describe` will return "nothing").
+Since this command has no output, there is no point in piping it with other commands.
+`print` may be used inside blocks of code (e.g.: hooks) to display text during execution without interfering with the pipeline.
+When used inside a pipeline it passes the input forward as output without interfering with it.
+"#
+    }
+
+    fn run(
+        &self,
+        engine_state: &EngineState,
+        stack: &mut Stack,
+        call: &Call,
+        input: PipelineData,
+    ) -> Result<PipelineData, ShellError> {
+        let args: Vec<Value> = call.rest(engine_state, stack, 0)?;
+        let no_newline = call.has_flag(engine_state, stack, "no-newline")?;
+        let to_stderr = call.has_flag(engine_state, stack, "stderr")?;
+
+        let input_val = input.into_value(Span::empty());
+
+        // This will allow for easy printing of pipelines as well
+        if !args.is_empty() {
+            for arg in args {
+                arg.into_pipeline_data()
+                    .print(engine_state, stack, no_newline, to_stderr)?;
+            }
+        } else if !input_val.is_nothing() {
+            input_val.clone().into_pipeline_data().print(
+                engine_state,
+                stack,
+                no_newline,
+                to_stderr,
+            )?;
+        }
+
+        Ok(input_val.into_pipeline_data())
+    }
+}

src/context/bindings.rs

@@ -2,7 +2,7 @@ use nu_cmd_lang::*;
 use nu_command::*;
 use nu_protocol::engine::{EngineState, StateWorkingSet};
 
-use crate::error::CrateResult;
+use crate::{commands::PrintCommand, error::CrateResult};
 
 macro_rules! bind_commands {
     ($engine_state:expr, $( $command:expr),* $(,)? ) => {
@@ -42,6 +42,7 @@ pub fn bind_core_commands(engine_state: &mut EngineState) -> CrateResult<()> {
         Hide,
         HideEnv,
         If,
+        PrintCommand,
         Ignore,
         Overlay,
         OverlayUse,
@@ -66,6 +67,7 @@ pub fn bind_debug_commands(engine_state: &mut EngineState) -> CrateResult<()> {
         engine_state,
         Ast,
         Debug,
+        DebugInfo,
         Explain,
         Inspect,
         Metadata,
@@ -106,6 +108,7 @@ pub fn bind_filter_commands(engine_state: &mut EngineState) -> CrateResult<()> {
             GroupBy,
             Headers,
             Insert,
+            Items,
             Join,
             SplitBy,
             Take,

src/lib.rs

@@ -1,5 +1,6 @@
 #![doc=include_str!("../README.md")]
 pub(crate) mod argument;
+pub mod commands;
 pub(crate) mod context;
 pub(crate) mod error;
 pub(crate) mod into_expression;

tests/test_eval.rs

@@ -15,6 +15,16 @@ fn it_evals_strings() {
     ctx.print_pipeline(pipeline).unwrap()
 }
 
+#[test]
+fn it_evals_print() {
+    let mut ctx = get_context();
+    ctx.eval_raw(
+        r#"print "Hello World from this eval using print""#,
+        PipelineData::empty(),
+    )
+    .unwrap();
+}
+
 #[test]
 fn it_reports_parse_errors() {
     let mut ctx = get_context();