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use crate::ast::error::ParseError;
use crate::ast::lexer::Lexer;
use crate::ast::nodes::{Attr, Element, Interpolation, Node, Text};
use crate::ast::span_range::SpanRange;
use crate::ast::tok::Tok;
use crate::ast::PResult;
pub struct Parser<'a> {
toks: Vec<(Tok, SpanRange)>,
i: usize,
_src: &'a str,
}
impl<'a> Parser<'a> {
pub fn new(src: &'a str) -> Self {
Self {
toks: Lexer::new(src).all(),
i: 0,
_src: src,
}
}
pub fn parse_nodes(&mut self) -> PResult<Vec<Node>> {
let mut nodes = Vec::new();
while !self.eof() {
match self.cur() {
Some((Tok::LAngle, _)) => nodes.push(self.parse_element()?),
Some((Tok::LBrace, _)) => nodes.push(self.parse_i11n()?),
Some((Tok::Text(_), _)) => nodes.push(self.parse_text()?),
Some((tok, sp)) => {
return Err(ParseError {
msg: format!("unexpected token: {:?}", tok),
span: *sp,
});
}
None => break,
}
}
Ok(nodes)
}
fn eof(&self) -> bool {
self.i >= self.toks.len()
}
fn cur(&self) -> Option<&(Tok, SpanRange)> {
self.toks.get(self.i)
}
fn bump(&mut self) {
self.i += 1;
}
fn byte_end(&self) -> usize {
self.toks.last().map(|t| (t.1.end).0).unwrap_or(0)
}
fn expect(&mut self, want: Tok) -> PResult<SpanRange> {
if let Some((tok, sp)) = self.cur().cloned() {
if tok == want {
self.bump();
return Ok(sp);
}
}
let span = self
.cur()
.map(|t| t.1)
.unwrap_or_else(|| SpanRange::new(self.byte_end(), self.byte_end()));
Err(ParseError {
msg: format!("expected {:?}", want),
span,
})
}
fn parse_name(&mut self) -> PResult<(String, SpanRange)> {
match self.cur().cloned() {
Some((Tok::Text(s), sp)) => {
let mut name_end = s.len();
for (idx, ch) in s.char_indices() {
if ch.is_whitespace() || matches!(ch, '<' | '>' | '/' | '{' | '}') {
name_end = idx;
break;
}
}
if name_end == 0 {
return Err(ParseError {
msg: "invalid tag name".into(),
span: sp,
});
}
let name = s[..name_end].to_string();
self.bump();
let remainder = &s[name_end..];
if !remainder.is_empty() {
let rem_start = sp.start.0 + name_end;
// Insert directly at the current position of self.i - the next call to cur() will see it
self.toks.insert(
self.i,
(
Tok::Text(remainder.to_string()),
SpanRange::new(rem_start, sp.end.0),
),
);
}
let name_span = SpanRange::new(sp.start.0, sp.start.0 + name_end);
Ok((name, name_span))
}
Some((_tok, sp)) => Err(ParseError {
msg: "expected tag name".into(),
span: sp,
}),
None => Err(ParseError {
msg: "unexpected EOF when reading tag name".into(),
span: SpanRange::new(self.byte_end(), self.byte_end()),
}),
}
}
fn parse_element(&mut self) -> PResult<Node> {
let start = self.expect(Tok::LAngle)?.start;
let (name, _nsp) = self.parse_name()?;
// Collect the "tail" after the name until '>' or '/>'
let mut attrs_src = String::new();
let mut attrs_span_start = None;
let mut attrs_span_end = None;
loop {
match self.cur() {
Some((Tok::Slash, _)) => {
return if let Some((Tok::RAngle, sp_gt)) = self.toks.get(self.i + 1).cloned() {
self.bump(); // '/'
self.bump(); // '>'
let end = sp_gt.end;
let attrs = parse_attrs_from_buffer(
&attrs_src,
SpanRange {
start: attrs_span_start.unwrap_or(start),
end: attrs_span_end.unwrap_or(start),
},
)?;
Ok(Node::Element(Element {
name,
attrs,
children: vec![],
span: SpanRange { start, end },
}))
} else {
let sp = self.cur().unwrap().1;
Err(ParseError {
msg: "unexpected '/' in tag head".into(),
span: sp,
})
};
}
Some((Tok::RAngle, sp_gt)) => {
// Closed the opening tag: now parse the children or end empty
let end_open = *sp_gt;
self.bump();
let attrs = parse_attrs_from_buffer(
&attrs_src,
SpanRange {
start: attrs_span_start.unwrap_or(start),
end: attrs_span_end.unwrap_or(end_open.end),
},
)?;
let mut children = Vec::new();
loop {
match self.cur() {
Some((Tok::LAngle, _)) => {
if let Some((Tok::Slash, _)) = self.toks.get(self.i + 1) {
// </name>
self.bump(); // '<'
self.bump(); // '/'
let (close_name, sp_name) = self.parse_name()?;
if close_name != name {
return Err(ParseError {
msg: format!(
"unmatched closing tag: expected </{}>",
name
),
span: sp_name,
});
}
let end_angle = self.expect(Tok::RAngle)?;
return Ok(Node::Element(Element {
name,
attrs,
children,
span: SpanRange {
start,
end: end_angle.end,
},
}));
} else {
children.push(self.parse_element()?);
}
}
Some((Tok::LBrace, _)) => children.push(self.parse_i11n()?),
Some((Tok::Text(_), _)) => children.push(self.parse_text()?),
Some((tok, sp)) => {
return Err(ParseError {
msg: format!("unexpected token in element body: {:?}", tok),
span: *sp,
});
}
None => {
return Err(ParseError {
msg: "unexpected EOF in element body".into(),
span: SpanRange::new(self.byte_end(), self.byte_end()),
});
}
}
}
}
Some((Tok::Text(s), sp)) => {
// There can be spaces and attributes between the name and '>'
if attrs_span_start.is_none() {
attrs_span_start = Some(sp.start);
}
attrs_span_end = Some(sp.end);
attrs_src.push_str(s);
self.bump();
}
Some((tok, sp)) => {
return Err(ParseError {
msg: format!("unexpected token in tag head: {:?}", tok),
span: *sp,
});
}
None => {
return Err(ParseError {
msg: "unexpected EOF in tag head".into(),
span: SpanRange::new(self.byte_end(), self.byte_end()),
});
}
}
}
}
fn parse_text(&mut self) -> PResult<Node> {
let mut start = None;
let mut end = None;
let mut buf = String::new();
while let Some((Tok::Text(s), sp)) = self.cur().cloned() {
if start.is_none() {
start = Some(sp.start);
}
end = Some(sp.end);
self.bump();
buf.push_str(&s);
}
if let (Some(st), Some(en)) = (start, end) {
Ok(Node::Text(Text {
value: buf,
span: SpanRange { start: st, end: en },
}))
} else {
let span = self
.cur()
.map(|t| t.1)
.unwrap_or_else(|| SpanRange::new(self.byte_end(), self.byte_end()));
Err(ParseError {
msg: "expected text".into(),
span,
})
}
}
fn parse_i11n(&mut self) -> PResult<Node> {
let start = self.expect(Tok::LBrace)?.start;
// Read everything up to a single RBrace (}} was already converted to Text("}"))
let mut expr_src = String::new();
loop {
match self.cur().cloned() {
Some((Tok::RBrace, sp)) => {
self.bump();
return Ok(Node::I11n(Interpolation {
expr_src,
span: SpanRange { start, end: sp.end },
}));
}
Some((Tok::Text(s), _)) => {
expr_src.push_str(&s);
self.bump();
}
Some((Tok::LBrace, sp)) => {
// Nested { } are not supported (let's simplify the first version)
return Err(ParseError {
msg: "nested '{' in interpolation".into(),
span: sp,
});
}
Some((_tok, sp)) => {
return Err(ParseError {
msg: "unexpected token inside { }".into(),
span: sp,
});
}
None => {
return Err(ParseError {
msg: "unexpected EOF in { }".into(),
span: SpanRange::new(self.byte_end(), self.byte_end()),
});
}
}
}
}
}
fn parse_attrs_from_buffer(buf: &str, span: SpanRange) -> PResult<Vec<Attr>> {
let mut attrs = Vec::new();
let bytes = buf.as_bytes();
let mut i = 0usize;
let skip_ws = |b: &[u8], mut j: usize| {
while j < b.len() && b[j].is_ascii_whitespace() {
j += 1;
}
j
};
let is_name_char =
|c: u8| -> bool { c.is_ascii_alphanumeric() || c == b'_' || c == b'-' || c == b':' };
i = skip_ws(bytes, i);
while i < bytes.len() {
let name_start = i;
while i < bytes.len() && is_name_char(bytes[i]) {
i += 1;
}
if i == name_start {
// no name - maybe only spaces are left
i = skip_ws(bytes, i);
if i >= bytes.len() {
break;
}
return Err(ParseError {
msg: "invalid attribute name".into(),
span,
});
}
let name = &buf[name_start..i];
i = skip_ws(bytes, i);
if i >= bytes.len() || bytes[i] != b'=' {
return Err(ParseError {
msg: format!("expected '=' after attribute '{}'", name),
span,
});
}
i += 1;
i = skip_ws(bytes, i);
if i >= bytes.len() || (bytes[i] != b'"' && bytes[i] != b'\'') {
return Err(ParseError {
msg: format!("expected quote after '=' in attribute '{}'", name),
span,
});
}
let quote = bytes[i];
i += 1;
let val_start = i;
while i < bytes.len() && bytes[i] != quote {
i += 1;
}
if i >= bytes.len() {
return Err(ParseError {
msg: format!("unterminated quoted value for attribute '{}'", name),
span,
});
}
let value = &buf[val_start..i];
i += 1; // closing quote
attrs.push(Attr {
name: name.to_string(),
value: value.to_string(),
span,
});
i = skip_ws(bytes, i);
}
Ok(attrs)
}