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https://github.com/nushell/nushell.git
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c747ec75c9
# Description
When implementing a `Command`, one must also import all the types
present in the function signatures for `Command`. This makes it so that
we often import the same set of types in each command implementation
file. E.g., something like this:
```rust
use nu_protocol::ast::Call;
use nu_protocol::engine::{Command, EngineState, Stack};
use nu_protocol::{
record, Category, Example, IntoInterruptiblePipelineData, IntoPipelineData, PipelineData,
ShellError, Signature, Span, Type, Value,
};
```
This PR adds the `nu_engine::command_prelude` module which contains the
necessary and commonly used types to implement a `Command`:
```rust
// command_prelude.rs
pub use crate::CallExt;
pub use nu_protocol::{
ast::{Call, CellPath},
engine::{Command, EngineState, Stack},
record, Category, Example, IntoInterruptiblePipelineData, IntoPipelineData, IntoSpanned,
PipelineData, Record, ShellError, Signature, Span, Spanned, SyntaxShape, Type, Value,
};
```
This should reduce the boilerplate needed to implement a command and
also gives us a place to track the breadth of the `Command` API. I tried
to be conservative with what went into the prelude modules, since it
might be hard/annoying to remove items from the prelude in the future.
Let me know if something should be included or excluded.
110 lines
3.4 KiB
Rust
110 lines
3.4 KiB
Rust
use nu_engine::command_prelude::*;
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use nu_protocol::ast::{Argument, Expr, Expression};
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#[derive(Clone)]
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pub struct KnownExternal {
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pub name: String,
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pub signature: Box<Signature>,
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pub usage: String,
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pub extra_usage: String,
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}
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impl Command for KnownExternal {
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fn name(&self) -> &str {
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&self.name
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}
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fn signature(&self) -> Signature {
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*self.signature.clone()
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}
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fn usage(&self) -> &str {
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&self.usage
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}
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fn is_known_external(&self) -> bool {
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true
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}
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fn is_builtin(&self) -> bool {
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false
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}
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fn run(
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&self,
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engine_state: &EngineState,
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stack: &mut Stack,
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call: &Call,
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input: PipelineData,
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) -> Result<PipelineData, ShellError> {
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let head_span = call.head;
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let decl_id = engine_state
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.find_decl("run-external".as_bytes(), &[])
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.ok_or(ShellError::ExternalNotSupported { span: head_span })?;
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let command = engine_state.get_decl(decl_id);
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let mut extern_call = Call::new(head_span);
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let extern_name = if let Some(name_bytes) = engine_state.find_decl_name(call.decl_id, &[]) {
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String::from_utf8_lossy(name_bytes)
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} else {
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return Err(ShellError::NushellFailedSpanned {
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msg: "known external name not found".to_string(),
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label: "could not find name for this command".to_string(),
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span: call.head,
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});
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};
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let extern_name: Vec<_> = extern_name.split(' ').collect();
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let arg_extern_name = Expression {
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expr: Expr::String(extern_name[0].to_string()),
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span: call.head,
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ty: Type::String,
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custom_completion: None,
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};
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extern_call.add_positional(arg_extern_name);
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for subcommand in extern_name.into_iter().skip(1) {
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extern_call.add_positional(Expression {
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expr: Expr::String(subcommand.to_string()),
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span: call.head,
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ty: Type::String,
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custom_completion: None,
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});
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}
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for arg in &call.arguments {
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match arg {
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Argument::Positional(positional) => extern_call.add_positional(positional.clone()),
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Argument::Named(named) => {
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if let Some(short) = &named.1 {
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extern_call.add_positional(Expression {
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expr: Expr::String(format!("-{}", short.item)),
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span: named.0.span,
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ty: Type::String,
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custom_completion: None,
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});
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} else {
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extern_call.add_positional(Expression {
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expr: Expr::String(format!("--{}", named.0.item)),
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span: named.0.span,
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ty: Type::String,
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custom_completion: None,
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});
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}
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if let Some(arg) = &named.2 {
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extern_call.add_positional(arg.clone());
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}
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}
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Argument::Unknown(unknown) => extern_call.add_unknown(unknown.clone()),
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Argument::Spread(args) => extern_call.add_spread(args.clone()),
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}
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}
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command.run(engine_state, stack, &extern_call, input)
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}
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}
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