Add str title-case (#5573)

Co-authored-by: kyle <kyle@archtop.local>

crates/nu-command/src/default_context.rs

@@ -194,6 +194,7 @@ pub fn create_default_context(cwd: impl AsRef<Path>) -> EngineState {
             StrStartsWith,
             StrSubstring,
             StrTrim,
+            StrTitleCase,
             StrUpcase
         };
 

crates/nu-command/src/strings/str_/case/mod.rs

@@ -6,6 +6,7 @@ pub mod pascal_case;
 pub mod screaming_snake_case;
 pub mod snake_case;
 pub mod str_;
+pub mod title_case;
 pub mod upcase;
 
 pub use camel_case::SubCommand as StrCamelCase;
@@ -16,6 +17,7 @@ pub use pascal_case::SubCommand as StrPascalCase;
 pub use screaming_snake_case::SubCommand as StrScreamingSnakeCase;
 pub use snake_case::SubCommand as StrSnakeCase;
 pub use str_::Str;
+pub use title_case::SubCommand as StrTitleCase;
 pub use upcase::SubCommand as StrUpcase;
 
 use nu_engine::CallExt;

crates/nu-command/src/strings/str_/case/title_case.rs

@@ -0,0 +1,92 @@
+use inflector::cases::titlecase::to_title_case;
+use nu_protocol::ast::Call;
+use nu_protocol::engine::{Command, EngineState, Stack};
+use nu_protocol::{
+    Category, Example, PipelineData, ShellError, Signature, Span, SyntaxShape, Value,
+};
+
+use crate::operate;
+
+#[derive(Clone)]
+pub struct SubCommand;
+
+impl Command for SubCommand {
+    fn name(&self) -> &str {
+        "str title-case"
+    }
+
+    fn signature(&self) -> Signature {
+        Signature::build("str title-case")
+            .rest(
+                "rest",
+                SyntaxShape::CellPath,
+                "optionally convert text to Title Case by column paths",
+            )
+            .category(Category::Strings)
+    }
+
+    fn usage(&self) -> &str {
+        "Convert a string to Title Case"
+    }
+
+    fn run(
+        &self,
+        engine_state: &EngineState,
+        stack: &mut Stack,
+        call: &Call,
+        input: PipelineData,
+    ) -> Result<PipelineData, ShellError> {
+        operate(engine_state, stack, call, input, &to_title_case)
+    }
+
+    fn examples(&self) -> Vec<Example> {
+        vec![
+            Example {
+                description: "convert a string to Title Case",
+                example: "'nu-shell' | str title-case",
+                result: Some(Value::String {
+                    val: "Nu Shell".to_string(),
+                    span: Span::test_data(),
+                }),
+            },
+            Example {
+                description: "convert a string to Title Case",
+                example: "'this is a test case' | str title-case",
+                result: Some(Value::String {
+                    val: "This Is A Test Case".to_string(),
+                    span: Span::test_data(),
+                }),
+            },
+            Example {
+                description: "convert a column from a table to Title Case",
+                example: r#"[[title, count]; ['nu test', 100]] | str title-case title"#,
+                result: Some(Value::List {
+                    vals: vec![Value::Record {
+                        span: Span::test_data(),
+                        cols: vec!["title".to_string(), "count".to_string()],
+                        vals: vec![
+                            Value::String {
+                                val: "Nu Test".to_string(),
+                                span: Span::test_data(),
+                            },
+                            Value::test_int(100),
+                        ],
+                    }],
+                    span: Span::test_data(),
+                }),
+            },
+        ]
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use super::*;
+
+    #[test]
+    fn test_examples() {
+        use crate::test_examples;
+
+        test_examples(SubCommand {})
+    }
+}