From 8dfa500c80a636ad3d981faa83384bb8b5115e05 Mon Sep 17 00:00:00 2001
From: Ian Manske <ian.manske@pm.me>
Date: Sun, 14 Jul 2024 10:51:20 -0700
Subject: [PATCH] Add helper functions

---
 .../nu-protocol/src/pipeline/pipeline_data.rs | 28 +++++++++++++++++++
 crates/nu-protocol/src/ty.rs                  |  4 +++
 2 files changed, 32 insertions(+)

diff --git a/crates/nu-protocol/src/pipeline/pipeline_data.rs b/crates/nu-protocol/src/pipeline/pipeline_data.rs
index a89337a6c2..0d1c0b3092 100644
--- a/crates/nu-protocol/src/pipeline/pipeline_data.rs
+++ b/crates/nu-protocol/src/pipeline/pipeline_data.rs
@@ -635,6 +635,34 @@ impl PipelineData {
             Ok(None)
         }
     }
+
+    pub fn unsupported_input_error(
+        self,
+        expected_type: impl Into<String>,
+        span: Span,
+    ) -> ShellError {
+        match self {
+            PipelineData::Empty => ShellError::PipelineEmpty { dst_span: span },
+            PipelineData::Value(value, ..) => ShellError::OnlySupportsThisInputType {
+                exp_input_type: expected_type.into(),
+                wrong_type: value.get_type().get_non_specified_string(),
+                dst_span: span,
+                src_span: value.span(),
+            },
+            PipelineData::ListStream(stream, ..) => ShellError::OnlySupportsThisInputType {
+                exp_input_type: expected_type.into(),
+                wrong_type: "list (stream)".into(),
+                dst_span: span,
+                src_span: stream.span(),
+            },
+            PipelineData::ByteStream(stream, ..) => ShellError::OnlySupportsThisInputType {
+                exp_input_type: expected_type.into(),
+                wrong_type: stream.type_().describe().into(),
+                dst_span: span,
+                src_span: stream.span(),
+            },
+        }
+    }
 }
 
 enum PipelineIteratorInner {
diff --git a/crates/nu-protocol/src/ty.rs b/crates/nu-protocol/src/ty.rs
index d5ea8c1554..7c004d81de 100644
--- a/crates/nu-protocol/src/ty.rs
+++ b/crates/nu-protocol/src/ty.rs
@@ -36,6 +36,10 @@ pub enum Type {
 }
 
 impl Type {
+    pub fn list(inner: Type) -> Self {
+        Self::List(Box::new(inner))
+    }
+
     pub fn record() -> Self {
         Self::Record([].into())
     }