nushell/crates/nu-command/src/formats/from/tsv.rs

use super::delimited::{from_delimited_data, trim_from_str, DelimitedReaderConfig};

use nu_engine::CallExt;
use nu_protocol::ast::Call;
use nu_protocol::engine::{Command, EngineState, Stack};
use nu_protocol::{
    record, Category, Example, PipelineData, ShellError, Signature, SyntaxShape, Type, Value,
};

#[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 {})
    }
}