use nu_engine::command_prelude::*; use nu_protocol::Config; use std::fmt::Write; #[derive(Clone)] pub struct ViewSource; impl Command for ViewSource { fn name(&self) -> &str { "view source" } fn usage(&self) -> &str { "View a block, module, or a definition." } fn signature(&self) -> nu_protocol::Signature { Signature::build("view source") .input_output_types(vec![(Type::Nothing, Type::String)]) .required("item", SyntaxShape::Any, "Name or block to view.") .category(Category::Debug) } fn run( &self, engine_state: &EngineState, stack: &mut Stack, call: &Call, _input: PipelineData, ) -> Result { let arg: Value = call.req(engine_state, stack, 0)?; let arg_span = arg.span(); match arg { Value::String { val, .. } => { if let Some(decl_id) = engine_state.find_decl(val.as_bytes(), &[]) { // arg is a command let decl = engine_state.get_decl(decl_id); let sig = decl.signature(); let vec_of_required = &sig.required_positional; let vec_of_optional = &sig.optional_positional; let rest = &sig.rest_positional; let vec_of_flags = &sig.named; let type_signatures = &sig.input_output_types; if decl.is_alias() { if let Some(alias) = &decl.as_alias() { let contents = String::from_utf8_lossy( engine_state.get_span_contents(alias.wrapped_call.span), ); Ok(Value::string(contents, call.head).into_pipeline_data()) } else { Ok(Value::string("no alias found", call.head).into_pipeline_data()) } } // gets vector of positionals. else if let Some(block_id) = decl.get_block_id() { let block = engine_state.get_block(block_id); if let Some(block_span) = block.span { let contents = engine_state.get_span_contents(block_span); // name of function let mut final_contents = String::new(); if val.contains(' ') { let _ = write!(&mut final_contents, "def \"{val}\" ["); } else { let _ = write!(&mut final_contents, "def {val} ["); }; if !vec_of_required.is_empty() || !vec_of_optional.is_empty() || vec_of_flags.len() != 1 || rest.is_some() { final_contents.push(' '); } for n in vec_of_required { let _ = write!(&mut final_contents, "{}: {} ", n.name, n.shape); // positional arguments } for n in vec_of_optional { if let Some(s) = n.default_value.clone() { let _ = write!( &mut final_contents, "{}: {} = {} ", n.name, n.shape, s.to_expanded_string(" ", &Config::default()) ); } else { let _ = write!(&mut final_contents, "{}?: {} ", n.name, n.shape); } } for n in vec_of_flags { // skip adding the help flag if n.long == "help" { continue; } let _ = write!(&mut final_contents, "--{}", n.long); if let Some(short) = n.short { let _ = write!(&mut final_contents, "(-{})", short); } if let Some(arg) = &n.arg { let _ = write!(&mut final_contents, ": {}", arg); } final_contents.push(' '); } if let Some(rest_arg) = rest { let _ = write!( &mut final_contents, "...{}:{}", rest_arg.name, rest_arg.shape ); } let len = type_signatures.len(); if len != 0 { final_contents.push_str("]: ["); let mut c = 0; for (insig, outsig) in type_signatures { c += 1; let s = format!("{} -> {}", insig, outsig); final_contents.push_str(&s); if c != len { final_contents.push_str(", ") } } } final_contents.push_str("] "); final_contents.push_str(&String::from_utf8_lossy(contents)); Ok(Value::string(final_contents, call.head).into_pipeline_data()) } else { Err(ShellError::GenericError { error: "Cannot view value".to_string(), msg: "the command does not have a viewable block span".to_string(), span: Some(arg_span), help: None, inner: vec![], }) } } else { Err(ShellError::GenericError { error: "Cannot view value".to_string(), msg: "the command does not have a viewable block".to_string(), span: Some(arg_span), help: None, inner: vec![], }) } } else if let Some(module_id) = engine_state.find_module(val.as_bytes(), &[]) { // arg is a module let module = engine_state.get_module(module_id); if let Some(module_span) = module.span { let contents = engine_state.get_span_contents(module_span); Ok(Value::string(String::from_utf8_lossy(contents), call.head) .into_pipeline_data()) } else { Err(ShellError::GenericError { error: "Cannot view value".to_string(), msg: "the module does not have a viewable block".to_string(), span: Some(arg_span), help: None, inner: vec![], }) } } else { Err(ShellError::GenericError { error: "Cannot view value".to_string(), msg: "this name does not correspond to a viewable value".to_string(), span: Some(arg_span), help: None, inner: vec![], }) } } value => { if let Ok(closure) = value.as_closure() { let block = engine_state.get_block(closure.block_id); if let Some(span) = block.span { let contents = engine_state.get_span_contents(span); Ok(Value::string(String::from_utf8_lossy(contents), call.head) .into_pipeline_data()) } else { Ok(Value::string("", call.head).into_pipeline_data()) } } else { Err(ShellError::GenericError { error: "Cannot view value".to_string(), msg: "this value cannot be viewed".to_string(), span: Some(arg_span), help: None, inner: vec![], }) } } } } fn examples(&self) -> Vec { vec![ Example { description: "View the source of a code block", example: r#"let abc = {|| echo 'hi' }; view source $abc"#, result: Some(Value::test_string("{|| echo 'hi' }")), }, Example { description: "View the source of a custom command", example: r#"def hi [] { echo 'Hi!' }; view source hi"#, result: Some(Value::test_string("def hi [] { echo 'Hi!' }")), }, Example { description: "View the source of a custom command, which participates in the caller environment", example: r#"def --env foo [] { $env.BAR = 'BAZ' }; view source foo"#, result: Some(Value::test_string("def foo [] { $env.BAR = 'BAZ' }")), }, Example { description: "View the source of a custom command with flags and arguments", example: r#"def test [a?:any --b:int ...rest:string] { echo 'test' }; view source test"#, result: Some(Value::test_string("def test [ a?: any --b: int ...rest: string] { echo 'test' }")), }, Example { description: "View the source of a module", example: r#"module mod-foo { export-env { $env.FOO_ENV = 'BAZ' } }; view source mod-foo"#, result: Some(Value::test_string(" export-env { $env.FOO_ENV = 'BAZ' }")), }, Example { description: "View the source of an alias", example: r#"alias hello = echo hi; view source hello"#, result: Some(Value::test_string("echo hi")), }, ] } }