Left Pad and Right Pad String (#2630)

* WIP

* left and right pad strings

* fixed some tests

crates/nu-cli/src/cli.rs

@@ -147,7 +147,9 @@ pub fn create_default_context(interactive: bool) -> Result<EvaluationContext, Bo
             whole_stream_command(StrEndsWith),
             whole_stream_command(StrCollect),
             whole_stream_command(StrLength),
+            whole_stream_command(StrLPad),
             whole_stream_command(StrReverse),
+            whole_stream_command(StrRPad),
             whole_stream_command(StrCamelCase),
             whole_stream_command(StrPascalCase),
             whole_stream_command(StrKebabCase),

crates/nu-cli/src/commands.rs

@@ -246,9 +246,9 @@ pub(crate) use split::{Split, SplitChars, SplitColumn, SplitRow};
 pub(crate) use split_by::SplitBy;
 pub(crate) use str_::{
     Str, StrCamelCase, StrCapitalize, StrCollect, StrContains, StrDowncase, StrEndsWith,
-    StrFindReplace, StrFrom, StrIndexOf, StrKebabCase, StrLength, StrPascalCase, StrReverse,
-    StrScreamingSnakeCase, StrSet, StrSnakeCase, StrStartsWith, StrSubstring, StrToDatetime,
-    StrToDecimal, StrToInteger, StrTrim, StrTrimLeft, StrTrimRight, StrUpcase,
+    StrFindReplace, StrFrom, StrIndexOf, StrKebabCase, StrLPad, StrLength, StrPascalCase, StrRPad,
+    StrReverse, StrScreamingSnakeCase, StrSet, StrSnakeCase, StrStartsWith, StrSubstring,
+    StrToDatetime, StrToDecimal, StrToInteger, StrTrim, StrTrimLeft, StrTrimRight, StrUpcase,
 };
 pub(crate) use table::Table;
 pub(crate) use tags::Tags;

crates/nu-cli/src/commands/str_/lpad.rs

@@ -0,0 +1,179 @@
+use crate::commands::WholeStreamCommand;
+use crate::prelude::*;
+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;
+
+#[derive(Deserialize)]
+struct Arguments {
+    length: Tagged<usize>,
+    character: Tagged<char>,
+    rest: Vec<ColumnPath>,
+}
+
+pub struct SubCommand;
+
+#[async_trait]
+impl WholeStreamCommand for SubCommand {
+    fn name(&self) -> &str {
+        "str lpad"
+    }
+
+    fn signature(&self) -> Signature {
+        Signature::build("str lpad")
+            .required_named("length", SyntaxShape::Int, "length to pad to", Some('l'))
+            .required_named(
+                "character",
+                SyntaxShape::String,
+                "character to pad with",
+                Some('c'),
+            )
+            .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"
+    }
+
+    async fn run(
+        &self,
+        args: CommandArgs,
+        registry: &CommandRegistry,
+    ) -> Result<OutputStream, ShellError> {
+        operate(args, registry).await
+    }
+
+    fn examples(&self) -> Vec<Example> {
+        vec![
+            Example {
+                description: "Left pad a string with a character a number of places",
+                example: "echo 'nushell' | str lpad -l 10 -c '*'",
+                result: Some(vec![
+                    UntaggedValue::string("***nushell").into_untagged_value()
+                ]),
+            },
+            Example {
+                description: "Left pad a string with a character a number of places",
+                example: "echo '123' | str lpad -l 10 -c '0'",
+                result: Some(vec![
+                    UntaggedValue::string("0000000123").into_untagged_value()
+                ]),
+            },
+            Example {
+                description: "Use lpad to truncate a string",
+                example: "echo '123456789' | str lpad -l 3 -c '0'",
+                result: Some(vec![UntaggedValue::string("123").into_untagged_value()]),
+            },
+        ]
+    }
+}
+
+async fn operate(
+    args: CommandArgs,
+    registry: &CommandRegistry,
+) -> Result<OutputStream, ShellError> {
+    let registry = registry.clone();
+
+    let (
+        Arguments {
+            length,
+            character,
+            rest,
+        },
+        input,
+    ) = args.process(&registry).await?;
+    let column_paths: Vec<_> = rest;
+
+    Ok(input
+        .map(move |v| {
+            let len = length.item;
+            let character = character.item;
+            if column_paths.is_empty() {
+                ReturnSuccess::value(action(&v, len, character, v.tag())?)
+            } else {
+                let mut ret = v;
+
+                for path in &column_paths {
+                    ret = ret.swap_data_by_column_path(
+                        path,
+                        Box::new(move |old| action(old, len, character, old.tag())),
+                    )?;
+                }
+
+                ReturnSuccess::value(ret)
+            }
+        })
+        .to_output_stream())
+}
+
+fn action(
+    input: &Value,
+    length: usize,
+    character: char,
+    tag: impl Into<Tag>,
+) -> Result<Value, ShellError> {
+    match &input.value {
+        UntaggedValue::Primitive(Primitive::Line(s))
+        | UntaggedValue::Primitive(Primitive::String(s)) => {
+            if length < s.len() {
+                Ok(UntaggedValue::string(&s[0..length]).into_value(tag))
+            } else {
+                let mut res = character.to_string().repeat(length - s.len());
+                res += s.as_ref();
+                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, SubCommand};
+    use nu_plugin::test_helpers::value::string;
+    use nu_protocol::UntaggedValue;
+    use nu_source::Tag;
+
+    #[test]
+    fn examples_work_as_expected() {
+        use crate::examples::test as test_examples;
+
+        test_examples(SubCommand {})
+    }
+
+    #[test]
+    fn left_pad_with_zeros() {
+        let word = string("123");
+        let pad_char = '0';
+        let pad_len = 10;
+        let expected = UntaggedValue::string("0000000123").into_untagged_value();
+
+        let actual = action(&word, pad_len, pad_char, Tag::unknown()).unwrap();
+        assert_eq!(actual, expected);
+    }
+
+    #[test]
+    fn left_pad_but_truncate() {
+        let word = string("123456789");
+        let pad_char = '0';
+        let pad_len = 3;
+        let expected = UntaggedValue::string("123").into_untagged_value();
+
+        let actual = action(&word, pad_len, pad_char, Tag::unknown()).unwrap();
+        assert_eq!(actual, expected);
+    }
+}

crates/nu-cli/src/commands/str_/mod.rs

@@ -9,7 +9,9 @@ mod find_replace;
 pub mod from;
 mod index_of;
 mod length;
+mod lpad;
 mod reverse;
+mod rpad;
 mod set;
 mod starts_with;
 mod substring;
@@ -34,7 +36,9 @@ pub use find_replace::SubCommand as StrFindReplace;
 pub use from::SubCommand as StrFrom;
 pub use index_of::SubCommand as StrIndexOf;
 pub use length::SubCommand as StrLength;
+pub use lpad::SubCommand as StrLPad;
 pub use reverse::SubCommand as StrReverse;
+pub use rpad::SubCommand as StrRPad;
 pub use set::SubCommand as StrSet;
 pub use starts_with::SubCommand as StrStartsWith;
 pub use substring::SubCommand as StrSubstring;

crates/nu-cli/src/commands/str_/rpad.rs

@@ -0,0 +1,179 @@
+use crate::commands::WholeStreamCommand;
+use crate::prelude::*;
+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;
+
+#[derive(Deserialize)]
+struct Arguments {
+    length: Tagged<usize>,
+    character: Tagged<char>,
+    rest: Vec<ColumnPath>,
+}
+
+pub struct SubCommand;
+
+#[async_trait]
+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(
+                SyntaxShape::ColumnPath,
+                "optionally check if string contains pattern by column paths",
+            )
+    }
+
+    fn usage(&self) -> &str {
+        "pad a string with a character a certain length"
+    }
+
+    async fn run(
+        &self,
+        args: CommandArgs,
+        registry: &CommandRegistry,
+    ) -> Result<OutputStream, ShellError> {
+        operate(args, registry).await
+    }
+
+    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()]),
+            },
+        ]
+    }
+}
+
+async fn operate(
+    args: CommandArgs,
+    registry: &CommandRegistry,
+) -> Result<OutputStream, ShellError> {
+    let registry = registry.clone();
+
+    let (
+        Arguments {
+            length,
+            character,
+            rest,
+        },
+        input,
+    ) = args.process(&registry).await?;
+    let column_paths: Vec<_> = rest;
+
+    Ok(input
+        .map(move |v| {
+            let len = length.item;
+            let character = character.item;
+            if column_paths.is_empty() {
+                ReturnSuccess::value(action(&v, len, character, v.tag())?)
+            } else {
+                let mut ret = v;
+
+                for path in &column_paths {
+                    ret = ret.swap_data_by_column_path(
+                        path,
+                        Box::new(move |old| action(old, len, character, old.tag())),
+                    )?;
+                }
+
+                ReturnSuccess::value(ret)
+            }
+        })
+        .to_output_stream())
+}
+
+fn action(
+    input: &Value,
+    length: usize,
+    character: char,
+    tag: impl Into<Tag>,
+) -> Result<Value, ShellError> {
+    match &input.value {
+        UntaggedValue::Primitive(Primitive::Line(s))
+        | UntaggedValue::Primitive(Primitive::String(s)) => {
+            if length < s.len() {
+                Ok(UntaggedValue::string(&s[0..length]).into_value(tag))
+            } else {
+                let mut res = s.to_string();
+                res += character.to_string().repeat(length - s.len()).as_str();
+                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, SubCommand};
+    use nu_plugin::test_helpers::value::string;
+    use nu_protocol::UntaggedValue;
+    use nu_source::Tag;
+
+    #[test]
+    fn examples_work_as_expected() {
+        use crate::examples::test as test_examples;
+
+        test_examples(SubCommand {})
+    }
+
+    #[test]
+    fn right_pad_with_zeros() {
+        let word = string("123");
+        let pad_char = '0';
+        let pad_len = 10;
+        let expected = UntaggedValue::string("1230000000").into_untagged_value();
+
+        let actual = action(&word, pad_len, pad_char, Tag::unknown()).unwrap();
+        assert_eq!(actual, expected);
+    }
+
+    #[test]
+    fn right_pad_but_truncate() {
+        let word = string("123456789");
+        let pad_char = '0';
+        let pad_len = 3;
+        let expected = UntaggedValue::string("123").into_untagged_value();
+
+        let actual = action(&word, pad_len, pad_char, Tag::unknown()).unwrap();
+        assert_eq!(actual, expected);
+    }
+}