nushell/crates/nu-command/src/formats/from/tsv.rs
Ian Manske c747ec75c9
Add command_prelude module (#12291)
# 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.
2024-03-26 21:17:30 +00:00

158 lines
5.3 KiB
Rust

use super::delimited::{from_delimited_data, trim_from_str, DelimitedReaderConfig};
use nu_engine::command_prelude::*;
#[derive(Clone)]
pub struct FromTsv;
impl Command for FromTsv {
fn name(&self) -> &str {
"from tsv"
}
fn signature(&self) -> Signature {
Signature::build("from tsv")
.input_output_types(vec![(Type::String, Type::Table(vec![]))])
.named(
"comment",
SyntaxShape::String,
"a comment character to ignore lines starting with it",
Some('c'),
)
.named(
"quote",
SyntaxShape::String,
"a quote character to ignore separators in strings, defaults to '\"'",
Some('q'),
)
.named(
"escape",
SyntaxShape::String,
"an escape character for strings containing the quote character",
Some('e'),
)
.switch(
"noheaders",
"don't treat the first row as column names",
Some('n'),
)
.switch(
"flexible",
"allow the number of fields in records to be variable",
None,
)
.switch("no-infer", "no field type inferencing", None)
.named(
"trim",
SyntaxShape::String,
"drop leading and trailing whitespaces around headers names and/or field values",
Some('t'),
)
.category(Category::Formats)
}
fn usage(&self) -> &str {
"Parse text as .tsv and create table."
}
fn run(
&self,
engine_state: &EngineState,
stack: &mut Stack,
call: &Call,
input: PipelineData,
) -> Result<PipelineData, ShellError> {
from_tsv(engine_state, stack, call, input)
}
fn examples(&self) -> Vec<Example> {
vec![
Example {
description: "Convert tab-separated data to a table",
example: "\"ColA\tColB\n1\t2\" | from tsv",
result: Some(Value::test_list (
vec![Value::test_record(record! {
"ColA" => Value::test_int(1),
"ColB" => Value::test_int(2),
})],
))
},
Example {
description: "Create a tsv file with header columns and open it",
example: r#"$'c1(char tab)c2(char tab)c3(char nl)1(char tab)2(char tab)3' | save tsv-data | open tsv-data | from tsv"#,
result: None,
},
Example {
description: "Create a tsv file without header columns and open it",
example: r#"$'a1(char tab)b1(char tab)c1(char nl)a2(char tab)b2(char tab)c2' | save tsv-data | open tsv-data | from tsv --noheaders"#,
result: None,
},
Example {
description: "Create a tsv file without header columns and open it, removing all unnecessary whitespaces",
example: r#"$'a1(char tab)b1(char tab)c1(char nl)a2(char tab)b2(char tab)c2' | save tsv-data | open tsv-data | from tsv --trim all"#,
result: None,
},
Example {
description: "Create a tsv file without header columns and open it, removing all unnecessary whitespaces in the header names",
example: r#"$'a1(char tab)b1(char tab)c1(char nl)a2(char tab)b2(char tab)c2' | save tsv-data | open tsv-data | from tsv --trim headers"#,
result: None,
},
Example {
description: "Create a tsv file without header columns and open it, removing all unnecessary whitespaces in the field values",
example: r#"$'a1(char tab)b1(char tab)c1(char nl)a2(char tab)b2(char tab)c2' | save tsv-data | open tsv-data | from tsv --trim fields"#,
result: None,
},
]
}
}
fn from_tsv(
engine_state: &EngineState,
stack: &mut Stack,
call: &Call,
input: PipelineData,
) -> Result<PipelineData, ShellError> {
let name = call.head;
let comment = call
.get_flag(engine_state, stack, "comment")?
.map(|v: Value| v.as_char())
.transpose()?;
let quote = call
.get_flag(engine_state, stack, "quote")?
.map(|v: Value| v.as_char())
.transpose()?
.unwrap_or('"');
let escape = call
.get_flag(engine_state, stack, "escape")?
.map(|v: Value| v.as_char())
.transpose()?;
let no_infer = call.has_flag(engine_state, stack, "no-infer")?;
let noheaders = call.has_flag(engine_state, stack, "noheaders")?;
let flexible = call.has_flag(engine_state, stack, "flexible")?;
let trim = trim_from_str(call.get_flag(engine_state, stack, "trim")?)?;
let config = DelimitedReaderConfig {
separator: '\t',
comment,
quote,
escape,
noheaders,
flexible,
no_infer,
trim,
};
from_delimited_data(config, input, name)
}
#[cfg(test)]
mod test {
use super::*;
#[test]
fn test_examples() {
use crate::test_examples;
test_examples(FromTsv {})
}
}