convert_case/converter.rs
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use crate::segmentation;
use crate::Boundary;
use crate::Case;
use crate::Pattern;
/// The parameters for performing a case conversion.
///
/// A `Converter` stores three fields needed for case conversion.
/// 1) `boundaries`: how a string is segmented into _words_.
/// 2) `pattern`: how words are mutated, or how each character's case will change.
/// 3) `delim` or delimeter: how the mutated words are joined into the final string.
///
/// Then calling [`convert`](Converter::convert) on a `Converter` will apply a case conversion
/// defined by those fields. The `Converter` struct is what is used underneath those functions
/// available in the `Casing` struct.
///
/// You can use `Converter` when you need more specificity on conversion
/// than those provided in `Casing`, or if it is simply more convenient or explicit.
///
/// ```
/// use convert_case::{Boundary, Case, Casing, Converter, Pattern};
///
/// let s = "DialogueBox-border-shadow";
///
/// // Convert using Casing trait
/// assert_eq!(
/// "dialoguebox_border_shadow",
/// s.from_case(Case::Kebab).to_case(Case::Snake)
/// );
///
/// // Convert using similar functions on Converter
/// let conv = Converter::new()
/// .from_case(Case::Kebab)
/// .to_case(Case::Snake);
/// assert_eq!("dialoguebox_border_shadow", conv.convert(s));
///
/// // Convert by setting each field explicitly.
/// let conv = Converter::new()
/// .set_boundaries(&[Boundary::Hyphen])
/// .set_pattern(Pattern::Lowercase)
/// .set_delim("_");
/// assert_eq!("dialoguebox_border_shadow", conv.convert(s));
/// ```
///
/// Or you can use `Converter` when you are trying to make a unique case
/// not provided as a variant of `Case`.
///
/// ```
/// use convert_case::{Boundary, Case, Casing, Converter, Pattern};
///
/// let dot_camel = Converter::new()
/// .set_boundaries(&[Boundary::LowerUpper, Boundary::LowerDigit])
/// .set_pattern(Pattern::Camel)
/// .set_delim(".");
/// assert_eq!("collision.Shape.2d", dot_camel.convert("CollisionShape2D"));
/// ```
pub struct Converter {
/// How a string is segmented into words.
pub boundaries: Vec<Boundary>,
/// How each word is mutated before joining. In the case that there is no pattern, none of the
/// words will be mutated before joining and will maintain whatever case they were in the
/// original string.
pub pattern: Option<Pattern>,
/// The string used to join mutated words together.
pub delim: String,
}
impl Default for Converter {
fn default() -> Self {
Converter {
boundaries: Boundary::defaults(),
pattern: None,
delim: String::new(),
}
}
}
impl Converter {
/// Creates a new `Converter` with default fields. This is the same as `Default::default()`.
/// The `Converter` will use `Boundary::defaults()` for boundaries, no pattern, and an empty
/// string as a delimeter.
/// ```
/// use convert_case::Converter;
///
/// let conv = Converter::new();
/// assert_eq!("DeathPerennialQUEST", conv.convert("Death-Perennial QUEST"))
/// ```
pub fn new() -> Self {
Self::default()
}
/// Converts a string.
/// ```
/// use convert_case::{Case, Converter};
///
/// let conv = Converter::new()
/// .to_case(Case::Camel);
/// assert_eq!("xmlHttpRequest", conv.convert("XML_HTTP_Request"))
/// ```
pub fn convert<T>(&self, s: T) -> String
where
T: AsRef<str>,
{
let words = segmentation::split(&s, &self.boundaries);
if let Some(p) = self.pattern {
let words = words.iter().map(|s| s.as_ref()).collect::<Vec<&str>>();
p.mutate(&words).join(&self.delim)
} else {
words.join(&self.delim)
}
}
/// Set the pattern and delimiter to those associated with the given case.
/// ```
/// use convert_case::{Case, Converter};
///
/// let conv = Converter::new()
/// .to_case(Case::Pascal);
/// assert_eq!("VariableName", conv.convert("variable name"))
/// ```
pub fn to_case(mut self, case: Case) -> Self {
self.pattern = Some(case.pattern());
self.delim = case.delim().to_string();
self
}
/// Sets the boundaries to those associated with the provided case. This is used
/// by the `from_case` function in the `Casing` trait.
/// ```
/// use convert_case::{Case, Converter};
///
/// let conv = Converter::new()
/// .from_case(Case::Snake)
/// .to_case(Case::Title);
/// assert_eq!("Dot Productvalue", conv.convert("dot_productValue"))
/// ```
pub fn from_case(mut self, case: Case) -> Self {
self.boundaries = case.boundaries();
self
}
/// Sets the boundaries to those provided.
/// ```
/// use convert_case::{Boundary, Case, Converter};
///
/// let conv = Converter::new()
/// .set_boundaries(&[Boundary::Underscore, Boundary::LowerUpper])
/// .to_case(Case::Lower);
/// assert_eq!("panic attack dream theater", conv.convert("panicAttack_dreamTheater"))
/// ```
pub fn set_boundaries(mut self, bs: &[Boundary]) -> Self {
self.boundaries = bs.to_vec();
self
}
/// Adds a boundary to the list of boundaries.
/// ```
/// use convert_case::{Boundary, Case, Converter};
///
/// let conv = Converter::new()
/// .from_case(Case::Title)
/// .add_boundary(Boundary::Hyphen)
/// .to_case(Case::Snake);
/// assert_eq!("my_biography_video_1", conv.convert("My Biography - Video 1"))
/// ```
pub fn add_boundary(mut self, b: Boundary) -> Self {
self.boundaries.push(b);
self
}
/// Adds a vector of boundaries to the list of boundaries.
/// ```
/// use convert_case::{Boundary, Case, Converter};
///
/// let conv = Converter::new()
/// .from_case(Case::Kebab)
/// .to_case(Case::Title)
/// .add_boundaries(&[Boundary::Underscore, Boundary::LowerUpper]);
/// assert_eq!("2020 10 First Day", conv.convert("2020-10_firstDay"));
/// ```
pub fn add_boundaries(mut self, bs: &[Boundary]) -> Self {
self.boundaries.extend(bs);
self
}
/// Removes a boundary from the list of boundaries if it exists.
/// ```
/// use convert_case::{Boundary, Case, Converter};
///
/// let conv = Converter::new()
/// .remove_boundary(Boundary::Acronym)
/// .to_case(Case::Kebab);
/// assert_eq!("httprequest-parser", conv.convert("HTTPRequest_parser"));
/// ```
pub fn remove_boundary(mut self, b: Boundary) -> Self {
self.boundaries.retain(|&x| x != b);
self
}
/// Removes all the provided boundaries from the list of boundaries if it exists.
/// ```
/// use convert_case::{Boundary, Case, Converter};
///
/// let conv = Converter::new()
/// .remove_boundaries(&Boundary::digits())
/// .to_case(Case::Snake);
/// assert_eq!("c04_s03_path_finding.pdf", conv.convert("C04 S03 Path Finding.pdf"));
/// ```
pub fn remove_boundaries(mut self, bs: &[Boundary]) -> Self {
for b in bs {
self.boundaries.retain(|&x| x != *b);
}
self
}
/// Sets the delimeter.
/// ```
/// use convert_case::{Case, Converter};
///
/// let conv = Converter::new()
/// .to_case(Case::Snake)
/// .set_delim(".");
/// assert_eq!("lower.with.dots", conv.convert("LowerWithDots"));
/// ```
pub fn set_delim<T>(mut self, d: T) -> Self
where
T: ToString,
{
self.delim = d.to_string();
self
}
/// Sets the delimeter to an empty string.
/// ```
/// use convert_case::{Case, Converter};
///
/// let conv = Converter::new()
/// .to_case(Case::Snake)
/// .remove_delim();
/// assert_eq!("nodelimshere", conv.convert("No Delims Here"));
/// ```
pub fn remove_delim(mut self) -> Self {
self.delim = String::new();
self
}
/// Sets the pattern.
/// ```
/// use convert_case::{Case, Converter, Pattern};
///
/// let conv = Converter::new()
/// .set_delim("_")
/// .set_pattern(Pattern::Sentence);
/// assert_eq!("Bjarne_case", conv.convert("BJARNE CASE"));
/// ```
pub fn set_pattern(mut self, p: Pattern) -> Self {
self.pattern = Some(p);
self
}
/// Sets the pattern field to `None`. Where there is no pattern, a character's case is never
/// mutated and will be maintained at the end of conversion.
/// ```
/// use convert_case::{Case, Converter};
///
/// let conv = Converter::new()
/// .from_case(Case::Title)
/// .to_case(Case::Snake)
/// .remove_pattern();
/// assert_eq!("KoRn_Alone_I_Break", conv.convert("KoRn Alone I Break"));
/// ```
pub fn remove_pattern(mut self) -> Self {
self.pattern = None;
self
}
}
#[cfg(test)]
mod test {
use super::*;
use crate::Casing;
use crate::Pattern;
#[test]
fn snake_converter_from_case() {
let conv = Converter::new().to_case(Case::Snake);
let s = String::from("my var name");
assert_eq!(s.to_case(Case::Snake), conv.convert(s));
}
#[test]
fn snake_converter_from_scratch() {
let conv = Converter::new()
.set_delim("_")
.set_pattern(Pattern::Lowercase);
let s = String::from("my var name");
assert_eq!(s.to_case(Case::Snake), conv.convert(s));
}
#[test]
fn custom_pattern() {
let conv = Converter::new()
.to_case(Case::Snake)
.set_pattern(Pattern::Sentence);
assert_eq!("Bjarne_case", conv.convert("bjarne case"));
}
#[test]
fn custom_delim() {
let conv = Converter::new().set_delim("..");
assert_eq!("oh..My", conv.convert("ohMy"));
}
#[test]
fn no_pattern() {
let conv = Converter::new()
.from_case(Case::Title)
.to_case(Case::Kebab)
.remove_pattern();
assert_eq!("wIErd-CASing", conv.convert("wIErd CASing"));
}
#[test]
fn no_delim() {
let conv = Converter::new()
.from_case(Case::Title)
.to_case(Case::Kebab)
.remove_delim();
assert_eq!("justflat", conv.convert("Just Flat"));
}
#[test]
fn no_digit_boundaries() {
let conv = Converter::new()
.remove_boundaries(&Boundary::digits())
.to_case(Case::Snake);
assert_eq!("test_08bound", conv.convert("Test 08Bound"));
assert_eq!("a8a_a8a", conv.convert("a8aA8A"));
}
#[test]
fn remove_boundary() {
let conv = Converter::new()
.remove_boundary(Boundary::DigitUpper)
.to_case(Case::Snake);
assert_eq!("test_08bound", conv.convert("Test 08Bound"));
assert_eq!("a_8_a_a_8a", conv.convert("a8aA8A"));
}
#[test]
fn add_boundary() {
let conv = Converter::new()
.from_case(Case::Snake)
.to_case(Case::Kebab)
.add_boundary(Boundary::LowerUpper);
assert_eq!("word-word-word", conv.convert("word_wordWord"));
}
#[test]
fn add_boundaries() {
let conv = Converter::new()
.from_case(Case::Snake)
.to_case(Case::Kebab)
.add_boundaries(&[Boundary::LowerUpper, Boundary::UpperLower]);
assert_eq!("word-word-w-ord", conv.convert("word_wordWord"));
}
#[test]
fn reuse_after_change() {
let conv = Converter::new().from_case(Case::Snake).to_case(Case::Kebab);
assert_eq!("word-wordword", conv.convert("word_wordWord"));
let conv = conv.add_boundary(Boundary::LowerUpper);
assert_eq!("word-word-word", conv.convert("word_wordWord"));
}
#[test]
fn explicit_boundaries() {
let conv = Converter::new()
.set_boundaries(&[
Boundary::DigitLower,
Boundary::DigitUpper,
Boundary::Acronym,
])
.to_case(Case::Snake);
assert_eq!(
"section8_lesson2_http_requests",
conv.convert("section8lesson2HTTPRequests")
);
}
}