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|
use nom::{self, IResult};
use std::str;
pub enum Expr<'a> {
Var(&'a [u8]),
Filter(&'a str, Box<Expr<'a>>),
}
pub enum Node<'a> {
Lit(&'a [u8]),
Expr(Expr<'a>),
}
fn take_content(i: &[u8]) -> IResult<&[u8], Node> {
if i.len() < 1 || i[0] == b'{' {
return IResult::Error(error_position!(nom::ErrorKind::TakeUntil, i));
}
for (j, c) in i.iter().enumerate() {
if *c == b'{' {
if i.len() < j + 2 {
return IResult::Done(&i[..0], Node::Lit(&i[..]));
} else if i[j + 1] == '{' as u8 {
return IResult::Done(&i[j..], Node::Lit(&i[..j]));
} else if i[j + 1] == '%' as u8 {
return IResult::Done(&i[j..], Node::Lit(&i[..j]));
}
}
}
IResult::Done(&i[..0], Node::Lit(&i[..]))
}
named!(expr_var<Expr>, map!(nom::alphanumeric, Expr::Var));
fn expr_filtered(i: &[u8]) -> IResult<&[u8], Expr> {
let (mut left, mut expr) = match expr_var(i) {
IResult::Error(err) => { return IResult::Error(err); },
IResult::Incomplete(needed) => { return IResult::Incomplete(needed); },
IResult::Done(left, res) => (left, res),
};
while left[0] == b'|' {
match nom::alphanumeric(&left[1..]) {
IResult::Error(err) => {
return IResult::Error(err);
},
IResult::Incomplete(needed) => {
return IResult::Incomplete(needed);
},
IResult::Done(new_left, res) => {
left = new_left;
expr = Expr::Filter(str::from_utf8(res).unwrap(), Box::new(expr));
},
};
}
return IResult::Done(left, expr);
}
named!(expr_node<Node>, map!(
delimited!(tag_s!("{{"), ws!(expr_filtered), tag_s!("}}")),
Node::Expr));
named!(parse_template< Vec<Node> >, many1!(alt!(take_content | expr_node)));
pub fn parse<'a>(src: &'a str) -> Vec<Node> {
match parse_template(src.as_bytes()) {
IResult::Done(_, res) => res,
IResult::Error(err) => panic!("problems parsing template source: {}", err),
IResult::Incomplete(_) => panic!("parsing incomplete"),
}
}
|
