nushell/crates/nu-command/src/experimental/view_source.rs
2022-02-15 17:03:06 -05:00

103 lines
4.1 KiB
Rust

use nu_engine::CallExt;
use nu_protocol::ast::Call;
use nu_protocol::engine::{Command, EngineState, Stack};
use nu_protocol::{
Category, IntoPipelineData, PipelineData, ShellError, Signature, SyntaxShape, 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")
.desc(self.usage())
.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()) {
// arg is a command
let decl = engine_state.get_decl(decl_id);
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);
Ok(Value::string(String::from_utf8_lossy(contents), call.head)
.into_pipeline_data())
} else {
Err(ShellError::SpannedLabeledError(
"Cannot view value".to_string(),
"the command does not have a viewable block".to_string(),
arg_span,
))
}
} else {
Err(ShellError::SpannedLabeledError(
"Cannot view value".to_string(),
"the command does not have a viewable block".to_string(),
arg_span,
))
}
} else if let Some(overlay_id) = engine_state.find_overlay(val.as_bytes()) {
// arg is a module
let overlay = engine_state.get_overlay(overlay_id);
if let Some(overlay_span) = overlay.span {
let contents = engine_state.get_span_contents(&overlay_span);
Ok(Value::string(String::from_utf8_lossy(contents), call.head)
.into_pipeline_data())
} else {
Err(ShellError::SpannedLabeledError(
"Cannot view value".to_string(),
"the module does not have a viewable block".to_string(),
arg_span,
))
}
} else {
Err(ShellError::SpannedLabeledError(
"Cannot view value".to_string(),
"this name does not correspond to a viewable value".to_string(),
arg_span,
))
}
}
_ => Err(ShellError::SpannedLabeledError(
"Cannot view value".to_string(),
"this value cannot be viewed".to_string(),
arg_span,
)),
}
}
}