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#[macro_use]
extern crate derive_builder;
#[derive(Builder, PartialEq, Debug)]
struct Lorem {
ipsum: String,
#[builder(default = "self.default_dolor()?")]
dolor: String,
#[builder(default = "self.default_sit()?")]
sit: String,
#[builder(setter(skip), default = "self.default_amet()")]
amet: String,
}
impl LoremBuilder {
fn default_dolor(&self) -> Result<String, String> {
self.ipsum
.clone()
.ok_or_else(|| "ipsum must be initialized to build dolor".to_string())
}
fn default_sit(&self) -> Result<String, String> {
match self.ipsum {
Some(ref x) if x.chars().count() > 3 => Ok(format!("sit {}", x)),
_ => Err("ipsum must at least 3 chars to build sit".to_string()),
}
}
fn default_amet(&self) -> String {
if let Some(ref x) = self.ipsum {
format!("amet {}", x)
} else {
"..nothing there".to_string()
}
}
}
fn main() {
let x = LoremBuilder::default()
.ipsum("ipsum".to_string())
.build()
.unwrap();
assert_eq!(
x,
Lorem {
ipsum: "ipsum".to_string(),
dolor: "ipsum".to_string(),
sit: "sit ipsum".to_string(),
amet: "amet ipsum".to_string(),
}
);
}
|
