use itertools::Itertools;
use nu_engine::CallExt;
use nu_protocol::ast::Call;
use nu_protocol::engine::{Command, EngineState, Stack};
use nu_protocol::{
Category, Example, IntoPipelineData, PipelineData, ShellError, Signature, SyntaxShape, Type,
Value,
};
#[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::Core)
}
fn run(
&self,
engine_state: &EngineState,
stack: &mut Stack,
call: &Call,
_input: PipelineData,
) -> Result<nu_protocol::PipelineData, nu_protocol::ShellError> {
let arg: Value = call.req(engine_state, stack, 0)?;
let arg_span = arg.span()?;
match arg {
Value::Block { val: block_id, .. } => {
let block = engine_state.get_block(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("<internal command>", call.head).into_pipeline_data())
}
}
Value::String { val, .. } => {
if let Some(decl_id) = engine_state.find_decl(val.as_bytes(), &[]) {
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 vec_of_flags = &sig.named;
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);
let mut final_contents = String::from("def ");
final_contents.push_str(&val);
final_contents.push_str(" [ ");
for n in vec_of_required {
final_contents.push_str(&n.name);
final_contents.push(':');
final_contents.push_str(&n.shape.to_string());
final_contents.push(' ');
}
for n in vec_of_optional {
final_contents.push_str(&n.name);
final_contents.push_str("?:");
final_contents.push_str(&n.shape.to_string());
final_contents.push(' ');
}
for n in vec_of_flags {
final_contents.push_str("--");
final_contents.push_str(&n.long);
final_contents.push(' ');
if n.short.is_some() {
final_contents.push_str("(-");
final_contents.push(n.short.expect("this cannot trigger."));
final_contents.push(')');
}
if n.arg.is_some() {
final_contents.push_str(": ");
final_contents.push_str(
&n.arg.as_ref().expect("this cannot trigger.").to_string(),
);
}
final_contents.push(' ');
}
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(
"Cannot view value".to_string(),
"the command does not have a viewable block".to_string(),
Some(arg_span),
None,
Vec::new(),
))
}
} else {
Err(ShellError::GenericError(
"Cannot view value".to_string(),
"the command does not have a viewable block".to_string(),
Some(arg_span),
None,
Vec::new(),
))
}
} else if let Some(module_id) = engine_state.find_module(val.as_bytes(), &[]) {
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(
"Cannot view value".to_string(),
"the module does not have a viewable block".to_string(),
Some(arg_span),
None,
Vec::new(),
))
}
} else if let Some(alias_id) = engine_state.find_alias(val.as_bytes(), &[]) {
let contents = &mut engine_state.get_alias(alias_id).iter().map(|span| {
String::from_utf8_lossy(engine_state.get_span_contents(span)).to_string()
});
Ok(Value::String {
val: contents.join(" "),
span: call.head,
}
.into_pipeline_data())
} else {
Err(ShellError::GenericError(
"Cannot view value".to_string(),
"this name does not correspond to a viewable value".to_string(),
Some(arg_span),
None,
Vec::new(),
))
}
}
_ => Err(ShellError::GenericError(
"Cannot view value".to_string(),
"this value cannot be viewed".to_string(),
Some(arg_span),
None,
Vec::new(),
)),
}
}
fn examples(&self) -> Vec<Example> {
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("{ echo 'Hi!' }")),
},
Example {
description: "View the source of a custom command, which participates in the caller environment",
example: r#"def-env foo [] { let-env BAR = 'BAZ' }; view-source foo"#,
result: Some(Value::test_string("{ let-env BAR = 'BAZ' }")),
},
Example {
description: "View the source of a module",
example: r#"module mod-foo { export-env { let-env FOO_ENV = 'BAZ' } }; view-source mod-foo"#,
result: Some(Value::test_string(" export-env { let-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")),
},
]
}
}