Add 'str length' command (#2102)

crates/nu-cli/src/cli.rs

@@ -305,6 +305,7 @@ pub fn create_default_context(
             whole_stream_command(StrToDatetime),
             whole_stream_command(StrTrim),
             whole_stream_command(StrCollect),
+            whole_stream_command(StrLength),
             whole_stream_command(BuildString),
             whole_stream_command(Ansi),
             whole_stream_command(Char),

crates/nu-cli/src/commands.rs

@@ -244,7 +244,7 @@ pub(crate) use split::SplitColumn;
 pub(crate) use split::SplitRow;
 pub(crate) use split_by::SplitBy;
 pub(crate) use str_::{
-    Str, StrCapitalize, StrCollect, StrDowncase, StrFindReplace, StrSet, StrSubstring,
+    Str, StrCapitalize, StrCollect, StrDowncase, StrFindReplace, StrLength, StrSet, StrSubstring,
     StrToDatetime, StrToDecimal, StrToInteger, StrTrim, StrUpcase,
 };
 #[allow(unused_imports)]

crates/nu-cli/src/commands/str_/length.rs

@@ -0,0 +1,65 @@
+use crate::commands::WholeStreamCommand;
+use crate::prelude::*;
+use nu_errors::ShellError;
+use nu_protocol::{ReturnSuccess, Signature, UntaggedValue};
+
+pub struct SubCommand;
+
+#[async_trait]
+impl WholeStreamCommand for SubCommand {
+    fn name(&self) -> &str {
+        "str length"
+    }
+
+    fn signature(&self) -> Signature {
+        Signature::build("str length")
+    }
+
+    fn usage(&self) -> &str {
+        "outputs the lengths of the strings in the pipeline"
+    }
+
+    async fn run(
+        &self,
+        args: CommandArgs,
+        _registry: &CommandRegistry,
+    ) -> Result<OutputStream, ShellError> {
+        Ok(args
+            .input
+            .map(move |x| match x.as_string() {
+                Ok(s) => ReturnSuccess::value(UntaggedValue::int(s.len()).into_untagged_value()),
+                Err(err) => Err(err),
+            })
+            .to_output_stream())
+    }
+
+    fn examples(&self) -> Vec<Example> {
+        vec![
+            Example {
+                description: "Return the lengths of multiple strings",
+                example: "echo 'hello' | str length",
+                result: Some(vec![UntaggedValue::int(5).into_untagged_value()]),
+            },
+            Example {
+                description: "Return the lengths of multiple strings",
+                example: "echo 'hi' 'there' | str length",
+                result: Some(vec![
+                    UntaggedValue::int(2).into_untagged_value(),
+                    UntaggedValue::int(5).into_untagged_value(),
+                ]),
+            },
+        ]
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::SubCommand;
+
+    #[test]
+    fn examples_work_as_expected() {
+        use crate::examples::test as test_examples;
+
+        test_examples(SubCommand {})
+    }
+}

crates/nu-cli/src/commands/str_/mod.rs

@@ -3,6 +3,7 @@ mod collect;
 mod command;
 mod downcase;
 mod find_replace;
+mod length;
 mod set;
 mod substring;
 mod to_datetime;
@@ -16,6 +17,7 @@ pub use collect::SubCommand as StrCollect;
 pub use command::Command as Str;
 pub use downcase::SubCommand as StrDowncase;
 pub use find_replace::SubCommand as StrFindReplace;
+pub use length::SubCommand as StrLength;
 pub use set::SubCommand as StrSet;
 pub use substring::SubCommand as StrSubstring;
 pub use to_datetime::SubCommand as StrToDatetime;