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use std::fmt;
use std::string::ToString;
extern crate pest;
#[macro_use]
extern crate pest_derive;
use pest::Parser;
use pest::iterators::Pairs;
#[derive(Parser)]
#[grammar = "grammar.pest"]
struct DIDParser;
pub struct DID {
pub method: String,
pub id_segments: Vec<String>,
pub params: Vec<(String, Option<String>)>,
pub path_segments: Vec<String>,
pub query: Option<String>,
pub fragment: Option<String>
}
impl DID {
pub fn parse<T>(input: T) -> Result<Self, String>
where T: ToString {
let input_str = input.to_string();
let pairs_res = DIDParser::parse(Rule::did, &*input_str);
match pairs_res {
Ok(pairs) => return Ok(pairs_to_parsed(pairs)),
Err(err) => return Err(err.to_string())
}
}
}
impl fmt::Display for DID {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
let mut out: String = String::from("did:");
out = out + self.method.as_str();
if self.id_segments.is_empty() {
out = out + ":";
} else {
for id in self.id_segments.iter() {
out = out + ":" + id;
}
}
for param in &self.params {
out = out + ";" + param.0.as_str();
match ¶m.1 {
Some(value) => out = out + "=" + value.as_str(),
None => {}
}
}
for seg in &self.path_segments {
out = out + "/" + seg.as_str();
}
match &self.query {
Some(q) => out = out + "?" + q.as_str(),
None => {}
}
match &self.fragment {
Some(f) => out = out + "#" + f.as_str(),
None => {}
}
write!(f, "{}", out)
}
}
fn pairs_to_parsed(pairs: Pairs<Rule>) -> DID {
let mut method: String = "".to_string();
let mut id_segments: Vec<String> = Vec::new();
let mut params: Vec<(String, Option<String>)> = Vec::new();
let mut path_segments: Vec<String> = Vec::new();
let mut query: Option<String> = None;
let mut fragment: Option<String> = None;
for pair in pairs {
match pair.as_rule() {
Rule::method => {
method = pair.as_str().to_string();
}
Rule::id_segment => {
id_segments.push(pair.as_str().to_string());
}
Rule::param => {
let mut inner = pair.into_inner();
let name = inner.next().expect("parameter with no name");
match inner.next() {
Some(value) => {
params.push((
name.as_str().to_string(),
Some(value.as_str().to_string())
));
},
None => {
params.push((
name.as_str().to_string(),
None
));
}
}
}
Rule::path_segment => {
path_segments.push(pair.as_str().to_string());
}
Rule::query => {
query = Some(pair.as_str().to_string());
}
Rule::fragment => {
fragment = Some(pair.as_str().to_string());
}
_ => unreachable!("unexpected inner rule in 'did'")
}
}
DID {
method,
id_segments,
params,
path_segments,
query,
fragment
}
}