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use std::{borrow::Cow, fmt};
pub struct Amanda<'raw> {
tokens: Vec<Token<'raw>>,
set_vars: Vec<SetVar>,
}
impl<'raw> Amanda<'raw> {
pub fn has(&self, var: &str) -> bool {
for tok in &self.tokens {
if let Token::Variable { name } = tok
&& var.eq(*name)
{
return true;
}
}
false
}
pub fn set<K: Into<Cow<'static, str>>, V: fmt::Display>(&mut self, key: K, value: V) {
self.set_vars.push(SetVar {
name: key.into(),
value: value.to_string(),
});
}
pub fn set_many<K: Into<Cow<'static, str>> + Copy, V: fmt::Display, I>(
&mut self,
key: K,
slice: I,
) where
I: Iterator<Item = V>,
{
slice.for_each(|item| self.set(key, item));
}
pub fn parse(raw: &'raw str) -> Self {
let mut tokens = vec![];
let mut curr = raw;
loop {
if curr.is_empty() {
break;
}
match curr.char_indices().find(|(_, ch)| *ch == '{') {
None => {
tokens.push(Token::text(curr));
break;
}
Some((open, _)) => match curr.char_indices().find(|(_, ch)| *ch == '}') {
None => {
tokens.push(Token::text(curr));
break;
}
Some((close, _)) => {
let before = &curr[..open];
let key = &curr[open + 1..close];
let after = &curr[close + 1..];
if key.contains(char::is_whitespace) {
tokens.push(Token::text(&curr[..=close]));
curr = after;
} else {
if !before.is_empty() {
tokens.push(Token::text(before));
}
tokens.push(Token::var(key));
curr = after;
}
}
},
}
}
Amanda {
tokens,
set_vars: vec![],
}
}
}
impl<'raw> fmt::Display for Amanda<'raw> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
for tok in &self.tokens {
match tok {
Token::Text(txt) => write!(f, "{txt}")?,
Token::Variable { name } => {
let mut set_one = false;
for set in self.set_vars.iter().filter(|sv| sv.name.eq(name)) {
set_one = true;
write!(f, "{}", set.value)?;
}
if !set_one {
write!(f, "{{{name}}}")?;
}
}
}
}
Ok(())
}
}
struct SetVar {
name: Cow<'static, str>,
value: String,
}
#[derive(Copy, Clone, Debug, PartialEq)]
enum Token<'raw> {
Text(&'raw str),
Variable { name: &'raw str },
}
impl<'raw> Token<'raw> {
pub fn text(text: &'raw str) -> Self {
Self::Text(text)
}
pub fn var(name: &'raw str) -> Self {
Self::Variable { name }
}
}
#[cfg(test)]
mod test {
use crate::amanda::{Amanda, Token};
#[test]
fn parses_text() {
let raw = "text";
let expected = vec![Token::text("text")];
let actual = Amanda::parse(raw);
assert_eq!(actual.tokens, expected)
}
#[test]
fn parses_variable() {
let raw = "{foo}";
let expected = vec![Token::var("foo")];
let actual = Amanda::parse(raw);
assert_eq!(actual.tokens, expected)
}
#[test]
fn parses_text_and_varaible() {
let raw = "text {var}";
let expected = vec![Token::text("text "), Token::var("var")];
let actual = Amanda::parse(raw);
assert_eq!(actual.tokens, expected)
}
#[test]
fn parses_sequential_variables() {
let raw = "{foo}{bar}{bing}";
let expected = vec![Token::var("foo"), Token::var("bar"), Token::var("bing")];
let actual = Amanda::parse(raw);
assert_eq!(actual.tokens, expected)
}
#[test]
fn parses_multiline_text() {
let raw = "one line\ntwo line\nthree line";
let expected = vec![Token::text(raw)];
let actual = Amanda::parse(raw);
assert_eq!(actual.tokens, expected)
}
#[test]
fn parses_complex() {
let raw = "Dear {name},\nI am contacting you today about your cars extended warranty.\n\nSincerely,\n{bad-agency}";
let expected = vec![
Token::text("Dear "),
Token::var("name"),
Token::text(
",\nI am contacting you today about your cars extended warranty.\n\nSincerely,\n",
),
Token::var("bad-agency"),
];
let actual = Amanda::parse(raw);
assert_eq!(actual.tokens, expected)
}
#[test]
fn replaces_var_once() {
let raw = "{foo}";
let mut am = Amanda::parse(raw);
am.set("foo", 27);
assert_eq!("27", am.to_string())
}
#[test]
fn replace_var_many() {
let raw = "{foo}";
let mut am = Amanda::parse(raw);
am.set_many("foo", ["(one)", "(two)"].iter());
assert_eq!("(one)(two)", am.to_string())
}
}
|
