nushell/src/commands/from_csv.rs

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use crate::object::{Primitive, SpannedDictBuilder, Value};
use crate::prelude::*;
use csv::ReaderBuilder;
pub fn from_csv_string_to_value(
s: String,
span: impl Into<Span>,
) -> Result<Spanned<Value>, Box<dyn std::error::Error>> {
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let mut reader = ReaderBuilder::new()
.has_headers(false)
.from_reader(s.as_bytes());
let span = span.into();
let mut fields: VecDeque<String> = VecDeque::new();
let mut iter = reader.records();
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let mut rows = vec![];
if let Some(result) = iter.next() {
let line = result?;
for item in line.iter() {
fields.push_back(item.to_string());
}
}
loop {
if let Some(row_values) = iter.next() {
let row_values = row_values?;
let mut row = SpannedDictBuilder::new(span);
for (idx, entry) in row_values.iter().enumerate() {
row.insert_spanned(
fields.get(idx).unwrap(),
Value::Primitive(Primitive::String(String::from(entry))).spanned(span),
);
}
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rows.push(row.into_spanned_value());
} else {
break;
}
}
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Ok(Spanned {
item: Value::List(rows),
span,
})
}
pub fn from_csv(args: CommandArgs) -> Result<OutputStream, ShellError> {
let out = args.input;
let span = args.call_info.name_span;
Ok(out
.values
.map(move |a| match a.item {
Value::Primitive(Primitive::String(s)) => match from_csv_string_to_value(s, span) {
Ok(x) => ReturnSuccess::value(x.spanned(a.span)),
Err(_) => Err(ShellError::maybe_labeled_error(
"Could not parse as CSV",
"piped data failed CSV parse",
span,
)),
},
_ => Err(ShellError::maybe_labeled_error(
"Expected string values from pipeline",
"expects strings from pipeline",
span,
)),
})
.to_output_stream())
}