add into string (#3403)

crates/nu-command/src/commands.rs

@@ -174,6 +174,7 @@ pub(crate) use if_::If;
 pub(crate) use into::Into;
 pub(crate) use into::IntoBinary;
 pub(crate) use into::IntoInt;
+pub(crate) use into::IntoString;
 pub(crate) use nu::NuPlugin;
 pub(crate) use update::Command as Update;
 pub(crate) mod kill;

crates/nu-command/src/commands/default_context.rs

@@ -123,6 +123,7 @@ pub fn create_default_context(interactive: bool) -> Result<EvaluationContext, Bo
             whole_stream_command(Into),
             whole_stream_command(IntoBinary),
             whole_stream_command(IntoInt),
+            whole_stream_command(IntoString),
             whole_stream_command(SplitBy),
             // Row manipulation
             whole_stream_command(All),

crates/nu-command/src/commands/into/mod.rs

@@ -1,7 +1,9 @@
 mod binary;
 mod command;
 mod int;
+mod string;
 
 pub use binary::SubCommand as IntoBinary;
 pub use command::Command as Into;
 pub use int::SubCommand as IntoInt;
+pub use string::SubCommand as IntoString;

crates/nu-command/src/commands/into/string.rs

@@ -0,0 +1,266 @@
+use crate::prelude::*;
+use nu_engine::WholeStreamCommand;
+use nu_errors::ShellError;
+use nu_protocol::{
+    ColumnPath, Primitive, ReturnSuccess, Signature, SyntaxShape, UntaggedValue, Value,
+};
+use nu_source::Tagged;
+use num_bigint::{BigInt, BigUint, ToBigInt};
+// TODO num_format::SystemLocale once platform-specific dependencies are stable (see Cargo.toml)
+use nu_data::base::shape::InlineShape;
+use num_format::Locale;
+use num_traits::{Pow, Signed};
+use std::iter;
+
+pub struct SubCommand;
+
+#[derive(Deserialize)]
+pub struct Arguments {
+    decimals: Option<Tagged<u64>>,
+    group_digits: bool,
+    column_paths: Vec<ColumnPath>,
+}
+
+impl WholeStreamCommand for SubCommand {
+    fn name(&self) -> &str {
+        "into string"
+    }
+
+    fn signature(&self) -> Signature {
+        Signature::build("into string")
+            .rest(
+                SyntaxShape::ColumnPath,
+                "column paths to convert to string (for table input)",
+            )
+            .named(
+                "decimals",
+                SyntaxShape::Int,
+                "decimal digits to which to round",
+                Some('d'),
+            )
+    }
+
+    fn usage(&self) -> &str {
+        "Convert value to string"
+    }
+
+    fn run_with_actions(&self, args: CommandArgs) -> Result<ActionStream, ShellError> {
+        into_string(args)
+    }
+
+    fn examples(&self) -> Vec<Example> {
+        vec![
+            Example {
+                description: "convert decimal to string and round to nearest integer",
+                example: "echo 1.7 | into string -d 0",
+                result: Some(vec![UntaggedValue::string("2").into_untagged_value()]),
+            },
+            Example {
+                description: "convert decimal to string",
+                example: "echo 4.3 | into string",
+                result: Some(vec![UntaggedValue::string("4.3").into_untagged_value()]),
+            },
+            Example {
+                description: "convert string to string",
+                example: "echo '1234' | into string",
+                result: Some(vec![UntaggedValue::string("1234").into_untagged_value()]),
+            },
+            Example {
+                description: "convert boolean to string",
+                example: "echo $true | into string",
+                result: Some(vec![UntaggedValue::string("true").into_untagged_value()]),
+            },
+            Example {
+                description: "convert date to string",
+                example: "date now | into string",
+                result: None,
+            },
+            Example {
+                description: "convert filepath to string",
+                example: "ls Cargo.toml | get name | into string",
+                result: None,
+            },
+            Example {
+                description: "convert filesize to string",
+                example: "ls Cargo.toml | get size | into string",
+                result: None,
+            },
+        ]
+    }
+}
+
+fn into_string(args: CommandArgs) -> Result<ActionStream, ShellError> {
+    let (options, input) = args.extract(|params| {
+        Ok(Arguments {
+            decimals: params.get_flag("decimals")?,
+            group_digits: false,
+            column_paths: params.rest_args()?,
+        })
+    })?;
+
+    let digits = options.decimals.as_ref().map(|tagged| tagged.item);
+    let group_digits = options.group_digits;
+
+    Ok(input
+        .map(move |v| {
+            if options.column_paths.is_empty() {
+                ReturnSuccess::value(action(&v, v.tag(), digits, group_digits)?)
+            } else {
+                let mut ret = v;
+                for path in &options.column_paths {
+                    ret = ret.swap_data_by_column_path(
+                        path,
+                        Box::new(move |old| action(old, old.tag(), digits, group_digits)),
+                    )?;
+                }
+
+                ReturnSuccess::value(ret)
+            }
+        })
+        .to_action_stream())
+}
+
+pub fn action(
+    input: &Value,
+    tag: impl Into<Tag>,
+    digits: Option<u64>,
+    group_digits: bool,
+) -> Result<Value, ShellError> {
+    match &input.value {
+        UntaggedValue::Primitive(prim) => Ok(UntaggedValue::string(match prim {
+            Primitive::Int(int) => {
+                if group_digits {
+                    format_bigint(int) // int.to_formatted_string(*locale)
+                } else {
+                    int.to_string()
+                }
+            }
+            Primitive::Decimal(dec) => format_decimal(dec.clone(), digits, group_digits),
+            Primitive::String(a_string) => a_string.to_string(),
+            Primitive::Boolean(a_bool) => a_bool.to_string(),
+            Primitive::Date(a_date) => a_date.format("%c").to_string(),
+            Primitive::FilePath(a_filepath) => a_filepath.as_path().display().to_string(),
+            Primitive::Filesize(a_filesize) => {
+                let byte_string = InlineShape::format_bytes(a_filesize, None);
+                byte_string.1
+            }
+            _ => {
+                return Err(ShellError::unimplemented(
+                    "str from for non-numeric primitives",
+                ))
+            }
+        })
+        .into_value(tag)),
+        UntaggedValue::Row(_) => Err(ShellError::labeled_error(
+            "specify column to use 'str from'",
+            "found table",
+            input.tag.clone(),
+        )),
+        _ => Err(ShellError::unimplemented(
+            "str from for non-primitive, non-table types",
+        )),
+    }
+}
+
+fn format_bigint(int: &BigInt) -> String {
+    format!("{}", int)
+
+    // TODO once platform-specific dependencies are stable (see Cargo.toml)
+    // #[cfg(windows)]
+    // {
+    //     int.to_formatted_string(&Locale::en)
+    // }
+    // #[cfg(not(windows))]
+    // {
+    //     match SystemLocale::default() {
+    //         Ok(locale) => int.to_formatted_string(&locale),
+    //         Err(_) => int.to_formatted_string(&Locale::en),
+    //     }
+    // }
+}
+
+fn format_decimal(mut decimal: BigDecimal, digits: Option<u64>, group_digits: bool) -> String {
+    if let Some(n) = digits {
+        decimal = round_decimal(&decimal, n)
+    }
+
+    if decimal.is_integer() && (digits.is_none() || digits == Some(0)) {
+        let int = decimal
+            .to_bigint()
+            .expect("integer BigDecimal should convert to BigInt");
+        return if group_digits {
+            int.to_string()
+        } else {
+            format_bigint(&int)
+        };
+    }
+
+    let (int, exp) = decimal.as_bigint_and_exponent();
+    let factor = BigInt::from(10).pow(BigUint::from(exp as u64)); // exp > 0 for non-int decimal
+    let int_part = &int / &factor;
+    let dec_part = (&int % &factor)
+        .abs()
+        .to_biguint()
+        .expect("BigInt::abs should always produce positive signed BigInt and thus BigUInt")
+        .to_str_radix(10);
+
+    let dec_str = if let Some(n) = digits {
+        dec_part
+            .chars()
+            .chain(iter::repeat('0'))
+            .take(n as usize)
+            .collect()
+    } else {
+        String::from(dec_part.trim_end_matches('0'))
+    };
+
+    let format_default_loc = |int_part: BigInt| {
+        let loc = Locale::en;
+        //TODO: when num_format is available for recent bigint, replace this with the locale-based format
+        let (int_str, sep) = (format!("{}", int_part), String::from(loc.decimal()));
+
+        format!("{}{}{}", int_str, sep, dec_str)
+    };
+
+    format_default_loc(int_part)
+
+    // TODO once platform-specific dependencies are stable (see Cargo.toml)
+    // #[cfg(windows)]
+    // {
+    //     format_default_loc(int_part)
+    // }
+    // #[cfg(not(windows))]
+    // {
+    //     match SystemLocale::default() {
+    //         Ok(sys_loc) => {
+    //             let int_str = int_part.to_formatted_string(&sys_loc);
+    //             let sep = String::from(sys_loc.decimal());
+    //             format!("{}{}{}", int_str, sep, dec_str)
+    //         }
+    //         Err(_) => format_default_loc(int_part),
+    //     }
+    // }
+}
+
+fn round_decimal(decimal: &BigDecimal, mut digits: u64) -> BigDecimal {
+    let mut mag = decimal.clone();
+    while mag >= BigDecimal::from(1) {
+        mag = mag / 10;
+        digits += 1;
+    }
+
+    decimal.with_prec(digits)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::ShellError;
+    use super::SubCommand;
+
+    #[test]
+    fn examples_work_as_expected() -> Result<(), ShellError> {
+        use crate::examples::test as test_examples;
+
+        test_examples(SubCommand {})
+    }
+}