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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.
84 lines
3.0 KiB
Rust
84 lines
3.0 KiB
Rust
use crate::{
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eval_block, eval_block_with_early_return, eval_expression, eval_expression_with_input,
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eval_subexpression,
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};
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use nu_protocol::{
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ast::{Block, Expression},
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debugger::{WithDebug, WithoutDebug},
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engine::{EngineState, Stack},
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PipelineData, ShellError, Value,
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};
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/// Type of eval_block() function
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pub type EvalBlockFn =
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fn(&EngineState, &mut Stack, &Block, PipelineData) -> Result<PipelineData, ShellError>;
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/// Type of eval_block_with_early_return() function
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pub type EvalBlockWithEarlyReturnFn =
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fn(&EngineState, &mut Stack, &Block, PipelineData) -> Result<PipelineData, ShellError>;
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/// Type of eval_expression() function
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pub type EvalExpressionFn = fn(&EngineState, &mut Stack, &Expression) -> Result<Value, ShellError>;
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/// Type of eval_expression_with_input() function
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pub type EvalExpressionWithInputFn = fn(
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&EngineState,
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&mut Stack,
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&Expression,
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PipelineData,
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) -> Result<(PipelineData, bool), ShellError>;
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/// Type of eval_subexpression() function
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pub type EvalSubexpressionFn =
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fn(&EngineState, &mut Stack, &Block, PipelineData) -> Result<PipelineData, ShellError>;
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/// Helper function to fetch `eval_block()` with the correct type parameter based on whether
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/// engine_state is configured with or without a debugger.
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pub fn get_eval_block(engine_state: &EngineState) -> EvalBlockFn {
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if engine_state.is_debugging() {
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eval_block::<WithDebug>
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} else {
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eval_block::<WithoutDebug>
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}
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}
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/// Helper function to fetch `eval_block_with_early_return()` with the correct type parameter based
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/// on whether engine_state is configured with or without a debugger.
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pub fn get_eval_block_with_early_return(engine_state: &EngineState) -> EvalBlockWithEarlyReturnFn {
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if engine_state.is_debugging() {
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eval_block_with_early_return::<WithDebug>
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} else {
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eval_block_with_early_return::<WithoutDebug>
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}
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}
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/// Helper function to fetch `eval_expression()` with the correct type parameter based on whether
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/// engine_state is configured with or without a debugger.
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pub fn get_eval_expression(engine_state: &EngineState) -> EvalExpressionFn {
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if engine_state.is_debugging() {
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eval_expression::<WithDebug>
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} else {
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eval_expression::<WithoutDebug>
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}
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}
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/// Helper function to fetch `eval_expression_with_input()` with the correct type parameter based
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/// on whether engine_state is configured with or without a debugger.
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pub fn get_eval_expression_with_input(engine_state: &EngineState) -> EvalExpressionWithInputFn {
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if engine_state.is_debugging() {
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eval_expression_with_input::<WithDebug>
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} else {
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eval_expression_with_input::<WithoutDebug>
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}
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}
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/// Helper function to fetch `eval_subexpression()` with the correct type parameter based on whether
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/// engine_state is configured with or without a debugger.
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pub fn get_eval_subexpression(engine_state: &EngineState) -> EvalSubexpressionFn {
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if engine_state.is_debugging() {
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eval_subexpression::<WithDebug>
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} else {
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eval_subexpression::<WithoutDebug>
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}
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}
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