nushell/crates/nu-command/src/commands/strings/str_/rpad.rs

use crate::prelude::*;
use nu_engine::WholeStreamCommand;
use nu_errors::ShellError;
use nu_protocol::ShellTypeName;
use nu_protocol::{
    ColumnPath, Primitive, ReturnSuccess, Signature, SyntaxShape, UntaggedValue, Value,
};
use nu_source::{Tag, Tagged};
use nu_value_ext::ValueExt;

struct Arguments {
    length: Tagged<usize>,
    character: Tagged<String>,
    column_paths: Vec<ColumnPath>,
}

pub struct SubCommand;

impl WholeStreamCommand for SubCommand {
    fn name(&self) -> &str {
        "str rpad"
    }

    fn signature(&self) -> Signature {
        Signature::build("str rpad")
            .required_named("length", SyntaxShape::Int, "length to pad to", Some('l'))
            .required_named(
                "character",
                SyntaxShape::String,
                "character to pad with",
                Some('c'),
            )
            .rest(
                "rest",
                SyntaxShape::ColumnPath,
                "optionally check if string contains pattern by column paths",
            )
    }

    fn usage(&self) -> &str {
        "pad a string with a character a certain length"
    }

    fn run_with_actions(&self, args: CommandArgs) -> Result<ActionStream, ShellError> {
        operate(args)
    }

    fn examples(&self) -> Vec<Example> {
        vec![
            Example {
                description: "Right pad a string with a character a number of places",
                example: "echo 'nushell' | str rpad -l 10 -c '*'",
                result: Some(vec![
                    UntaggedValue::string("nushell***").into_untagged_value()
                ]),
            },
            Example {
                description: "Right pad a string with a character a number of places",
                example: "echo '123' | str rpad -l 10 -c '0'",
                result: Some(vec![
                    UntaggedValue::string("1230000000").into_untagged_value()
                ]),
            },
            Example {
                description: "Use rpad to truncate a string",
                example: "echo '123456789' | str rpad -l 3 -c '0'",
                result: Some(vec![UntaggedValue::string("123").into_untagged_value()]),
            },
            Example {
                description: "Use rpad to pad Unicode",
                example: "echo '▉' | str rpad -l 10 -c '▉'",
                result: Some(vec![
                    UntaggedValue::string("▉▉▉▉▉▉▉▉▉▉").into_untagged_value()
                ]),
            },
        ]
    }
}

fn operate(args: CommandArgs) -> Result<ActionStream, ShellError> {
    let (options, input) = (
        Arc::new(Arguments {
            length: args.req_named("length")?,
            character: args.req_named("character")?,
            column_paths: args.rest(0)?,
        }),
        args.input,
    );

    Ok(input
        .map(move |v| {
            if options.column_paths.is_empty() {
                ReturnSuccess::value(action(&v, &options, v.tag())?)
            } else {
                let mut ret = v;

                for path in &options.column_paths {
                    let options = options.clone();

                    ret = ret.swap_data_by_column_path(
                        path,
                        Box::new(move |old| action(old, &options, old.tag())),
                    )?;
                }

                ReturnSuccess::value(ret)
            }
        })
        .into_action_stream())
}

fn action(
    input: &Value,
    Arguments {
        length, character, ..
    }: &Arguments,
    tag: impl Into<Tag>,
) -> Result<Value, ShellError> {
    match &input.value {
        UntaggedValue::Primitive(Primitive::String(s)) => {
            if **length < s.len() {
                Ok(
                    UntaggedValue::string(s.chars().take(**length).collect::<String>())
                        .into_value(tag),
                )
            } else {
                let mut res = s.to_string();
                res += &character.repeat(**length - s.chars().count());
                Ok(UntaggedValue::string(res).into_value(tag))
            }
        }
        other => {
            let got = format!("got {}", other.type_name());
            Err(ShellError::labeled_error(
                "value is not string",
                got,
                tag.into().span,
            ))
        }
    }
}

#[cfg(test)]
mod tests {
    use super::{action, Arguments, SubCommand};
    use nu_errors::ShellError;
    use nu_protocol::UntaggedValue;
    use nu_source::{Tag, TaggedItem};
    use nu_test_support::value::string;

    #[test]
    fn examples_work_as_expected() -> Result<(), ShellError> {
        use crate::examples::test as test_examples;

        test_examples(SubCommand {})
    }

    #[test]
    fn right_pad_with_zeros() {
        let word = string("123");

        let options = Arguments {
            character: String::from("0").tagged_unknown(),
            length: 10_usize.tagged_unknown(),
            column_paths: vec![],
        };

        let expected = UntaggedValue::string("1230000000").into_untagged_value();
        let actual = action(&word, &options, Tag::unknown()).unwrap();

        assert_eq!(actual, expected);
    }

    #[test]
    fn right_pad_but_truncate() {
        let word = string("123456789");

        let options = Arguments {
            character: String::from("0").tagged_unknown(),
            length: 3_usize.tagged_unknown(),
            column_paths: vec![],
        };

        let expected = UntaggedValue::string("123").into_untagged_value();
        let actual = action(&word, &options, Tag::unknown()).unwrap();

        assert_eq!(actual, expected);
    }
}