nushell/crates/nu-protocol/src/value/primitive.rs

347 lines
12 KiB
Rust
Raw Normal View History

use crate::type_name::ShellTypeName;
use crate::value::column_path::ColumnPath;
Add Range and start Signature support This commit contains two improvements: - Support for a Range syntax (and a corresponding Range value) - Work towards a signature syntax Implementing the Range syntax resulted in cleaning up how operators in the core syntax works. There are now two kinds of infix operators - tight operators (`.` and `..`) - loose operators Tight operators may not be interspersed (`$it.left..$it.right` is a syntax error). Loose operators require whitespace on both sides of the operator, and can be arbitrarily interspersed. Precedence is left to right in the core syntax. Note that delimited syntax (like `( ... )` or `[ ... ]`) is a single token node in the core syntax. A single token node can be parsed from beginning to end in a context-free manner. The rule for `.` is `<token node>.<member>`. The rule for `..` is `<token node>..<token node>`. Loose operators all have the same syntactic rule: `<token node><space><loose op><space><token node>`. The second aspect of this pull request is the beginning of support for a signature syntax. Before implementing signatures, a necessary prerequisite is for the core syntax to support multi-line programs. That work establishes a few things: - `;` and newlines are handled in the core grammar, and both count as "separators" - line comments begin with `#` and continue until the end of the line In this commit, multi-token productions in the core grammar can use separators interchangably with spaces. However, I think we will ultimately want a different rule preventing separators from occurring before an infix operator, so that the end of a line is always unambiguous. This would avoid gratuitous differences between modules and repl usage. We already effectively have this rule, because otherwise `x<newline> | y` would be a single pipeline, but of course that wouldn't work.
2019-12-04 22:14:52 +01:00
use crate::value::range::Range;
use crate::value::{serde_bigdecimal, serde_bigint};
use bigdecimal::BigDecimal;
use chrono::{DateTime, Utc};
Add Range and start Signature support This commit contains two improvements: - Support for a Range syntax (and a corresponding Range value) - Work towards a signature syntax Implementing the Range syntax resulted in cleaning up how operators in the core syntax works. There are now two kinds of infix operators - tight operators (`.` and `..`) - loose operators Tight operators may not be interspersed (`$it.left..$it.right` is a syntax error). Loose operators require whitespace on both sides of the operator, and can be arbitrarily interspersed. Precedence is left to right in the core syntax. Note that delimited syntax (like `( ... )` or `[ ... ]`) is a single token node in the core syntax. A single token node can be parsed from beginning to end in a context-free manner. The rule for `.` is `<token node>.<member>`. The rule for `..` is `<token node>..<token node>`. Loose operators all have the same syntactic rule: `<token node><space><loose op><space><token node>`. The second aspect of this pull request is the beginning of support for a signature syntax. Before implementing signatures, a necessary prerequisite is for the core syntax to support multi-line programs. That work establishes a few things: - `;` and newlines are handled in the core grammar, and both count as "separators" - line comments begin with `#` and continue until the end of the line In this commit, multi-token productions in the core grammar can use separators interchangably with spaces. However, I think we will ultimately want a different rule preventing separators from occurring before an infix operator, so that the end of a line is always unambiguous. This would avoid gratuitous differences between modules and repl usage. We already effectively have this rule, because otherwise `x<newline> | y` would be a single pipeline, but of course that wouldn't work.
2019-12-04 22:14:52 +01:00
use nu_errors::{ExpectedRange, ShellError};
use nu_source::{PrettyDebug, Span, SpannedItem};
use num_bigint::BigInt;
Add Range and start Signature support This commit contains two improvements: - Support for a Range syntax (and a corresponding Range value) - Work towards a signature syntax Implementing the Range syntax resulted in cleaning up how operators in the core syntax works. There are now two kinds of infix operators - tight operators (`.` and `..`) - loose operators Tight operators may not be interspersed (`$it.left..$it.right` is a syntax error). Loose operators require whitespace on both sides of the operator, and can be arbitrarily interspersed. Precedence is left to right in the core syntax. Note that delimited syntax (like `( ... )` or `[ ... ]`) is a single token node in the core syntax. A single token node can be parsed from beginning to end in a context-free manner. The rule for `.` is `<token node>.<member>`. The rule for `..` is `<token node>..<token node>`. Loose operators all have the same syntactic rule: `<token node><space><loose op><space><token node>`. The second aspect of this pull request is the beginning of support for a signature syntax. Before implementing signatures, a necessary prerequisite is for the core syntax to support multi-line programs. That work establishes a few things: - `;` and newlines are handled in the core grammar, and both count as "separators" - line comments begin with `#` and continue until the end of the line In this commit, multi-token productions in the core grammar can use separators interchangably with spaces. However, I think we will ultimately want a different rule preventing separators from occurring before an infix operator, so that the end of a line is always unambiguous. This would avoid gratuitous differences between modules and repl usage. We already effectively have this rule, because otherwise `x<newline> | y` would be a single pipeline, but of course that wouldn't work.
2019-12-04 22:14:52 +01:00
use num_traits::cast::{FromPrimitive, ToPrimitive};
use num_traits::identities::Zero;
use serde::{Deserialize, Serialize};
use std::path::PathBuf;
/// The most fundamental of structured values in Nu are the Primitive values. These values represent types like integers, strings, booleans, dates, etc that are then used
/// as the buildig blocks to build up more complex structures.
///
/// Primitives also include marker values BeginningOfStream and EndOfStream which denote a change of condition in the stream
#[derive(Debug, Clone, Ord, PartialOrd, Eq, PartialEq, Hash, Deserialize, Serialize)]
pub enum Primitive {
/// An empty value
Nothing,
/// A "big int", an integer with arbitrarily large size (aka not limited to 64-bit)
#[serde(with = "serde_bigint")]
Int(BigInt),
/// A "big decimal", an decimal number with arbitrarily large size (aka not limited to 64-bit)
#[serde(with = "serde_bigdecimal")]
Decimal(BigDecimal),
/// A count in the number of bytes, used as a filesize
Bytes(u64),
/// A string value
String(String),
/// A string value with an implied carriage return (or cr/lf) ending
Line(String),
/// A path to travel to reach a value in a table
ColumnPath(ColumnPath),
/// A glob pattern, eg foo*
Pattern(String),
/// A boolean value
Boolean(bool),
/// A date value, in UTC
Date(DateTime<Utc>),
/// A count in the number of seconds
Duration(u64),
/// A range of values
Add Range and start Signature support This commit contains two improvements: - Support for a Range syntax (and a corresponding Range value) - Work towards a signature syntax Implementing the Range syntax resulted in cleaning up how operators in the core syntax works. There are now two kinds of infix operators - tight operators (`.` and `..`) - loose operators Tight operators may not be interspersed (`$it.left..$it.right` is a syntax error). Loose operators require whitespace on both sides of the operator, and can be arbitrarily interspersed. Precedence is left to right in the core syntax. Note that delimited syntax (like `( ... )` or `[ ... ]`) is a single token node in the core syntax. A single token node can be parsed from beginning to end in a context-free manner. The rule for `.` is `<token node>.<member>`. The rule for `..` is `<token node>..<token node>`. Loose operators all have the same syntactic rule: `<token node><space><loose op><space><token node>`. The second aspect of this pull request is the beginning of support for a signature syntax. Before implementing signatures, a necessary prerequisite is for the core syntax to support multi-line programs. That work establishes a few things: - `;` and newlines are handled in the core grammar, and both count as "separators" - line comments begin with `#` and continue until the end of the line In this commit, multi-token productions in the core grammar can use separators interchangably with spaces. However, I think we will ultimately want a different rule preventing separators from occurring before an infix operator, so that the end of a line is always unambiguous. This would avoid gratuitous differences between modules and repl usage. We already effectively have this rule, because otherwise `x<newline> | y` would be a single pipeline, but of course that wouldn't work.
2019-12-04 22:14:52 +01:00
Range(Box<Range>),
/// A file path
Path(PathBuf),
/// A vector of raw binary data
#[serde(with = "serde_bytes")]
Binary(Vec<u8>),
/// Beginning of stream marker, a pseudo-value not intended for tables
BeginningOfStream,
/// End of stream marker, a pseudo-value not intended for tables
EndOfStream,
}
Add Range and start Signature support This commit contains two improvements: - Support for a Range syntax (and a corresponding Range value) - Work towards a signature syntax Implementing the Range syntax resulted in cleaning up how operators in the core syntax works. There are now two kinds of infix operators - tight operators (`.` and `..`) - loose operators Tight operators may not be interspersed (`$it.left..$it.right` is a syntax error). Loose operators require whitespace on both sides of the operator, and can be arbitrarily interspersed. Precedence is left to right in the core syntax. Note that delimited syntax (like `( ... )` or `[ ... ]`) is a single token node in the core syntax. A single token node can be parsed from beginning to end in a context-free manner. The rule for `.` is `<token node>.<member>`. The rule for `..` is `<token node>..<token node>`. Loose operators all have the same syntactic rule: `<token node><space><loose op><space><token node>`. The second aspect of this pull request is the beginning of support for a signature syntax. Before implementing signatures, a necessary prerequisite is for the core syntax to support multi-line programs. That work establishes a few things: - `;` and newlines are handled in the core grammar, and both count as "separators" - line comments begin with `#` and continue until the end of the line In this commit, multi-token productions in the core grammar can use separators interchangably with spaces. However, I think we will ultimately want a different rule preventing separators from occurring before an infix operator, so that the end of a line is always unambiguous. This would avoid gratuitous differences between modules and repl usage. We already effectively have this rule, because otherwise `x<newline> | y` would be a single pipeline, but of course that wouldn't work.
2019-12-04 22:14:52 +01:00
impl Primitive {
/// Converts a primitive value to a u64, if possible. Uses a span to build an error if the conversion isn't possible.
Add Range and start Signature support This commit contains two improvements: - Support for a Range syntax (and a corresponding Range value) - Work towards a signature syntax Implementing the Range syntax resulted in cleaning up how operators in the core syntax works. There are now two kinds of infix operators - tight operators (`.` and `..`) - loose operators Tight operators may not be interspersed (`$it.left..$it.right` is a syntax error). Loose operators require whitespace on both sides of the operator, and can be arbitrarily interspersed. Precedence is left to right in the core syntax. Note that delimited syntax (like `( ... )` or `[ ... ]`) is a single token node in the core syntax. A single token node can be parsed from beginning to end in a context-free manner. The rule for `.` is `<token node>.<member>`. The rule for `..` is `<token node>..<token node>`. Loose operators all have the same syntactic rule: `<token node><space><loose op><space><token node>`. The second aspect of this pull request is the beginning of support for a signature syntax. Before implementing signatures, a necessary prerequisite is for the core syntax to support multi-line programs. That work establishes a few things: - `;` and newlines are handled in the core grammar, and both count as "separators" - line comments begin with `#` and continue until the end of the line In this commit, multi-token productions in the core grammar can use separators interchangably with spaces. However, I think we will ultimately want a different rule preventing separators from occurring before an infix operator, so that the end of a line is always unambiguous. This would avoid gratuitous differences between modules and repl usage. We already effectively have this rule, because otherwise `x<newline> | y` would be a single pipeline, but of course that wouldn't work.
2019-12-04 22:14:52 +01:00
pub fn as_u64(&self, span: Span) -> Result<u64, ShellError> {
match self {
Primitive::Int(int) => match int.to_u64() {
None => Err(ShellError::range_error(
ExpectedRange::U64,
&format!("{}", int).spanned(span),
"converting an integer into a 64-bit integer",
)),
Some(num) => Ok(num),
},
other => Err(ShellError::type_error(
"integer",
other.type_name().spanned(span),
)),
}
}
}
impl num_traits::Zero for Primitive {
fn zero() -> Self {
Primitive::Int(BigInt::zero())
}
fn is_zero(&self) -> bool {
match self {
Primitive::Int(int) => int.is_zero(),
Primitive::Decimal(decimal) => decimal.is_zero(),
Primitive::Bytes(size) => size.is_zero(),
Primitive::Nothing => true,
_ => false,
}
}
}
impl std::ops::Add for Primitive {
type Output = Primitive;
fn add(self, rhs: Self) -> Self {
match (self, rhs) {
(Primitive::Int(left), Primitive::Int(right)) => Primitive::Int(left + right),
(Primitive::Int(left), Primitive::Decimal(right)) => {
Primitive::Decimal(BigDecimal::from(left) + right)
}
(Primitive::Decimal(left), Primitive::Decimal(right)) => {
Primitive::Decimal(left + right)
}
(Primitive::Decimal(left), Primitive::Int(right)) => {
Primitive::Decimal(left + BigDecimal::from(right))
}
(Primitive::Bytes(left), right) => match right {
Primitive::Bytes(right) => Primitive::Bytes(left + right),
Primitive::Int(right) => {
Primitive::Bytes(left + right.to_u64().unwrap_or_else(|| 0 as u64))
}
Primitive::Decimal(right) => {
Primitive::Bytes(left + right.to_u64().unwrap_or_else(|| 0 as u64))
}
_ => Primitive::Bytes(left),
},
(left, Primitive::Bytes(right)) => match left {
Primitive::Bytes(left) => Primitive::Bytes(left + right),
Primitive::Int(left) => {
Primitive::Bytes(left.to_u64().unwrap_or_else(|| 0 as u64) + right)
}
Primitive::Decimal(left) => {
Primitive::Bytes(left.to_u64().unwrap_or_else(|| 0 as u64) + right)
}
_ => Primitive::Bytes(right),
},
_ => Primitive::zero(),
}
}
}
impl std::ops::Mul for Primitive {
type Output = Self;
fn mul(self, rhs: Self) -> Self {
match (self, rhs) {
(Primitive::Int(left), Primitive::Int(right)) => Primitive::Int(left * right),
(Primitive::Int(left), Primitive::Decimal(right)) => {
Primitive::Decimal(BigDecimal::from(left) * right)
}
(Primitive::Decimal(left), Primitive::Decimal(right)) => {
Primitive::Decimal(left * right)
}
(Primitive::Decimal(left), Primitive::Int(right)) => {
Primitive::Decimal(left * BigDecimal::from(right))
}
_ => unimplemented!("Internal error: can't multiply incompatible primitives."),
}
}
}
impl From<BigDecimal> for Primitive {
/// Helper to convert from decimals to a Primitive value
fn from(decimal: BigDecimal) -> Primitive {
Primitive::Decimal(decimal)
}
}
impl From<BigInt> for Primitive {
/// Helper to convert from integers to a Primitive value
fn from(int: BigInt) -> Primitive {
Primitive::Int(int)
}
}
impl From<f64> for Primitive {
/// Helper to convert from 64-bit float to a Primitive value
fn from(float: f64) -> Primitive {
if let Some(f) = BigDecimal::from_f64(float) {
Primitive::Decimal(f)
} else {
unreachable!("Internal error: protocol did not use f64-compatible decimal")
}
}
}
impl ShellTypeName for Primitive {
/// Get the name of the type of a Primitive value
fn type_name(&self) -> &'static str {
match self {
Primitive::Nothing => "nothing",
Primitive::Int(_) => "integer",
Add Range and start Signature support This commit contains two improvements: - Support for a Range syntax (and a corresponding Range value) - Work towards a signature syntax Implementing the Range syntax resulted in cleaning up how operators in the core syntax works. There are now two kinds of infix operators - tight operators (`.` and `..`) - loose operators Tight operators may not be interspersed (`$it.left..$it.right` is a syntax error). Loose operators require whitespace on both sides of the operator, and can be arbitrarily interspersed. Precedence is left to right in the core syntax. Note that delimited syntax (like `( ... )` or `[ ... ]`) is a single token node in the core syntax. A single token node can be parsed from beginning to end in a context-free manner. The rule for `.` is `<token node>.<member>`. The rule for `..` is `<token node>..<token node>`. Loose operators all have the same syntactic rule: `<token node><space><loose op><space><token node>`. The second aspect of this pull request is the beginning of support for a signature syntax. Before implementing signatures, a necessary prerequisite is for the core syntax to support multi-line programs. That work establishes a few things: - `;` and newlines are handled in the core grammar, and both count as "separators" - line comments begin with `#` and continue until the end of the line In this commit, multi-token productions in the core grammar can use separators interchangably with spaces. However, I think we will ultimately want a different rule preventing separators from occurring before an infix operator, so that the end of a line is always unambiguous. This would avoid gratuitous differences between modules and repl usage. We already effectively have this rule, because otherwise `x<newline> | y` would be a single pipeline, but of course that wouldn't work.
2019-12-04 22:14:52 +01:00
Primitive::Range(_) => "range",
Primitive::Decimal(_) => "decimal",
Primitive::Bytes(_) => "bytes",
Primitive::String(_) => "string",
Primitive::Line(_) => "line",
Primitive::ColumnPath(_) => "column path",
Primitive::Pattern(_) => "pattern",
Primitive::Boolean(_) => "boolean",
Primitive::Date(_) => "date",
Primitive::Duration(_) => "duration",
Primitive::Path(_) => "file path",
Primitive::Binary(_) => "binary",
Primitive::BeginningOfStream => "marker<beginning of stream>",
Primitive::EndOfStream => "marker<end of stream>",
}
}
}
/// Format a Primitive value into a string
pub fn format_primitive(primitive: &Primitive, field_name: Option<&String>) -> String {
match primitive {
Primitive::Nothing => String::new(),
Primitive::BeginningOfStream => String::new(),
Primitive::EndOfStream => String::new(),
Primitive::Path(p) => format!("{}", p.display()),
Primitive::Bytes(b) => {
let byte = byte_unit::Byte::from_bytes(*b as u128);
if byte.get_bytes() == 0u128 {
return "".to_string();
}
let byte = byte.get_appropriate_unit(false);
match byte.get_unit() {
byte_unit::ByteUnit::B => format!("{} B ", byte.get_value()),
_ => byte.format(1),
}
}
Primitive::Duration(sec) => format_duration(*sec),
Primitive::Int(i) => i.to_string(),
2019-12-24 02:26:47 +01:00
Primitive::Decimal(decimal) => format!("{:.4}", decimal),
Add Range and start Signature support This commit contains two improvements: - Support for a Range syntax (and a corresponding Range value) - Work towards a signature syntax Implementing the Range syntax resulted in cleaning up how operators in the core syntax works. There are now two kinds of infix operators - tight operators (`.` and `..`) - loose operators Tight operators may not be interspersed (`$it.left..$it.right` is a syntax error). Loose operators require whitespace on both sides of the operator, and can be arbitrarily interspersed. Precedence is left to right in the core syntax. Note that delimited syntax (like `( ... )` or `[ ... ]`) is a single token node in the core syntax. A single token node can be parsed from beginning to end in a context-free manner. The rule for `.` is `<token node>.<member>`. The rule for `..` is `<token node>..<token node>`. Loose operators all have the same syntactic rule: `<token node><space><loose op><space><token node>`. The second aspect of this pull request is the beginning of support for a signature syntax. Before implementing signatures, a necessary prerequisite is for the core syntax to support multi-line programs. That work establishes a few things: - `;` and newlines are handled in the core grammar, and both count as "separators" - line comments begin with `#` and continue until the end of the line In this commit, multi-token productions in the core grammar can use separators interchangably with spaces. However, I think we will ultimately want a different rule preventing separators from occurring before an infix operator, so that the end of a line is always unambiguous. This would avoid gratuitous differences between modules and repl usage. We already effectively have this rule, because otherwise `x<newline> | y` would be a single pipeline, but of course that wouldn't work.
2019-12-04 22:14:52 +01:00
Primitive::Range(range) => format!(
"{}..{}",
format_primitive(&range.from.0.item, None),
format_primitive(&range.to.0.item, None)
),
Primitive::Pattern(s) => s.to_string(),
Primitive::String(s) => s.to_owned(),
Primitive::Line(s) => s.to_owned(),
Primitive::ColumnPath(p) => {
let mut members = p.iter();
let mut f = String::new();
f.push_str(
&members
.next()
.expect("BUG: column path with zero members")
.display(),
);
for member in members {
f.push_str(".");
f.push_str(&member.display())
}
f
}
Primitive::Boolean(b) => match (b, field_name) {
(true, None) => "Yes",
(false, None) => "No",
(true, Some(s)) if !s.is_empty() => s,
(false, Some(s)) if !s.is_empty() => "",
(true, Some(_)) => "Yes",
(false, Some(_)) => "No",
}
.to_owned(),
Primitive::Binary(_) => "<binary>".to_owned(),
Primitive::Date(d) => format_date(d),
}
}
Add Range and start Signature support This commit contains two improvements: - Support for a Range syntax (and a corresponding Range value) - Work towards a signature syntax Implementing the Range syntax resulted in cleaning up how operators in the core syntax works. There are now two kinds of infix operators - tight operators (`.` and `..`) - loose operators Tight operators may not be interspersed (`$it.left..$it.right` is a syntax error). Loose operators require whitespace on both sides of the operator, and can be arbitrarily interspersed. Precedence is left to right in the core syntax. Note that delimited syntax (like `( ... )` or `[ ... ]`) is a single token node in the core syntax. A single token node can be parsed from beginning to end in a context-free manner. The rule for `.` is `<token node>.<member>`. The rule for `..` is `<token node>..<token node>`. Loose operators all have the same syntactic rule: `<token node><space><loose op><space><token node>`. The second aspect of this pull request is the beginning of support for a signature syntax. Before implementing signatures, a necessary prerequisite is for the core syntax to support multi-line programs. That work establishes a few things: - `;` and newlines are handled in the core grammar, and both count as "separators" - line comments begin with `#` and continue until the end of the line In this commit, multi-token productions in the core grammar can use separators interchangably with spaces. However, I think we will ultimately want a different rule preventing separators from occurring before an infix operator, so that the end of a line is always unambiguous. This would avoid gratuitous differences between modules and repl usage. We already effectively have this rule, because otherwise `x<newline> | y` would be a single pipeline, but of course that wouldn't work.
2019-12-04 22:14:52 +01:00
/// Format a duration in seconds into a string
Add Range and start Signature support This commit contains two improvements: - Support for a Range syntax (and a corresponding Range value) - Work towards a signature syntax Implementing the Range syntax resulted in cleaning up how operators in the core syntax works. There are now two kinds of infix operators - tight operators (`.` and `..`) - loose operators Tight operators may not be interspersed (`$it.left..$it.right` is a syntax error). Loose operators require whitespace on both sides of the operator, and can be arbitrarily interspersed. Precedence is left to right in the core syntax. Note that delimited syntax (like `( ... )` or `[ ... ]`) is a single token node in the core syntax. A single token node can be parsed from beginning to end in a context-free manner. The rule for `.` is `<token node>.<member>`. The rule for `..` is `<token node>..<token node>`. Loose operators all have the same syntactic rule: `<token node><space><loose op><space><token node>`. The second aspect of this pull request is the beginning of support for a signature syntax. Before implementing signatures, a necessary prerequisite is for the core syntax to support multi-line programs. That work establishes a few things: - `;` and newlines are handled in the core grammar, and both count as "separators" - line comments begin with `#` and continue until the end of the line In this commit, multi-token productions in the core grammar can use separators interchangably with spaces. However, I think we will ultimately want a different rule preventing separators from occurring before an infix operator, so that the end of a line is always unambiguous. This would avoid gratuitous differences between modules and repl usage. We already effectively have this rule, because otherwise `x<newline> | y` would be a single pipeline, but of course that wouldn't work.
2019-12-04 22:14:52 +01:00
pub fn format_duration(sec: u64) -> String {
let (minutes, seconds) = (sec / 60, sec % 60);
let (hours, minutes) = (minutes / 60, minutes % 60);
let (days, hours) = (hours / 24, hours % 24);
match (days, hours, minutes, seconds) {
(0, 0, 0, 1) => "1 sec".to_owned(),
(0, 0, 0, s) => format!("{} secs", s),
(0, 0, m, s) => format!("{}:{:02}", m, s),
(0, h, m, s) => format!("{}:{:02}:{:02}", h, m, s),
(d, h, m, s) => format!("{}:{:02}:{:02}:{:02}", d, h, m, s),
}
}
/// Format a UTC date value into a humanized string (eg "1 week ago" instead of a formal date string)
pub fn format_date(d: &DateTime<Utc>) -> String {
let utc: DateTime<Utc> = Utc::now();
let duration = utc.signed_duration_since(*d);
if duration.num_weeks() >= 52 {
let num_years = duration.num_weeks() / 52;
format!(
"{} year{} ago",
num_years,
if num_years == 1 { "" } else { "s" }
)
} else if duration.num_weeks() >= 4 {
let num_months = duration.num_weeks() / 4;
format!(
"{} month{} ago",
num_months,
if num_months == 1 { "" } else { "s" }
)
} else if duration.num_weeks() >= 1 {
let num_weeks = duration.num_weeks();
format!(
"{} week{} ago",
num_weeks,
if num_weeks == 1 { "" } else { "s" }
)
} else if duration.num_days() >= 1 {
let num_days = duration.num_days();
format!(
"{} day{} ago",
num_days,
if num_days == 1 { "" } else { "s" }
)
} else if duration.num_hours() >= 1 {
let num_hours = duration.num_hours();
format!(
"{} hour{} ago",
num_hours,
if num_hours == 1 { "" } else { "s" }
)
} else if duration.num_minutes() >= 1 {
let num_minutes = duration.num_minutes();
format!(
"{} min{} ago",
num_minutes,
if num_minutes == 1 { "" } else { "s" }
)
} else {
let num_seconds = duration.num_seconds();
format!(
"{} sec{} ago",
num_seconds,
if num_seconds == 1 { "" } else { "s" }
)
}
}