267 lines
8.2 KiB
Rust
267 lines
8.2 KiB
Rust
use std::mem;
|
|
use syntax::ast::{Expr, ExprParen, Lit, Stmt, TokenTree, TtDelimited, TtToken};
|
|
use syntax::codemap::Span;
|
|
use syntax::ext::base::ExtCtxt;
|
|
use syntax::parse;
|
|
use syntax::parse::parser::Parser as RustParser;
|
|
use syntax::parse::token;
|
|
use syntax::ptr::P;
|
|
|
|
use super::render::{Escape, Renderer};
|
|
|
|
macro_rules! dollar {
|
|
() => (TtToken(_, token::Dollar))
|
|
}
|
|
macro_rules! dot {
|
|
() => (TtToken(_, token::Dot))
|
|
}
|
|
macro_rules! eq {
|
|
() => (TtToken(_, token::Eq))
|
|
}
|
|
macro_rules! not {
|
|
() => (TtToken(_, token::Not))
|
|
}
|
|
macro_rules! question {
|
|
() => (TtToken(_, token::Question))
|
|
}
|
|
macro_rules! semi {
|
|
() => (TtToken(_, token::Semi))
|
|
}
|
|
macro_rules! minus {
|
|
() => (TtToken(_, token::BinOp(token::Minus)))
|
|
}
|
|
macro_rules! slash {
|
|
() => (TtToken(_, token::BinOp(token::Slash)))
|
|
}
|
|
macro_rules! literal {
|
|
() => (TtToken(_, token::Literal(..)))
|
|
}
|
|
macro_rules! ident {
|
|
($x:pat) => (ident!(_, $x));
|
|
($sp:pat, $x:pat) => (TtToken($sp, token::Ident($x, token::IdentStyle::Plain)))
|
|
}
|
|
|
|
pub fn parse(cx: &ExtCtxt, input: &[TokenTree], sp: Span) -> P<Expr> {
|
|
let mut parser = Parser {
|
|
in_attr: false,
|
|
input: input,
|
|
span: sp,
|
|
render: Renderer::new(cx),
|
|
};
|
|
parser.markups();
|
|
parser.into_render().into_expr()
|
|
}
|
|
|
|
struct Parser<'cx, 's: 'cx, 'i> {
|
|
in_attr: bool,
|
|
input: &'i [TokenTree],
|
|
span: Span,
|
|
render: Renderer<'cx, 's>,
|
|
}
|
|
|
|
impl<'cx, 's, 'i> Parser<'cx, 's, 'i> {
|
|
/// Finalize the `Parser`, returning the `Renderer` underneath.
|
|
fn into_render(self) -> Renderer<'cx, 's> {
|
|
let Parser { render, .. } = self;
|
|
render
|
|
}
|
|
|
|
/// Consume `n` items from the input.
|
|
fn shift(&mut self, n: usize) {
|
|
self.input = &self.input[n..];
|
|
}
|
|
|
|
/// Construct a Rust AST parser from the given token tree.
|
|
fn new_rust_parser(&self, tts: Vec<TokenTree>) -> RustParser<'s> {
|
|
parse::tts_to_parser(self.render.cx.parse_sess, tts, self.render.cx.cfg.clone())
|
|
}
|
|
|
|
fn markups(&mut self) {
|
|
loop {
|
|
match self.input {
|
|
[] => return,
|
|
[semi!(), ..] => self.shift(1),
|
|
[_, ..] => if !self.markup() { return },
|
|
}
|
|
}
|
|
}
|
|
|
|
fn markup(&mut self) -> bool {
|
|
match self.input {
|
|
// Literal
|
|
[minus!(), ref tt @ literal!(), ..] => {
|
|
self.shift(2);
|
|
self.literal(tt, true)
|
|
},
|
|
[ref tt @ literal!(), ..] => {
|
|
self.shift(1);
|
|
self.literal(tt, false)
|
|
},
|
|
// Splice
|
|
[ref tt @ dollar!(), dollar!(), ..] => {
|
|
self.shift(2);
|
|
let expr = self.splice(tt.get_span());
|
|
self.render.splice(expr, Escape::PassThru);
|
|
},
|
|
[ref tt @ dollar!(), ..] => {
|
|
self.shift(1);
|
|
let expr = self.splice(tt.get_span());
|
|
self.render.splice(expr, Escape::Escape);
|
|
},
|
|
// Element
|
|
[ident!(sp, name), ..] => {
|
|
self.shift(1);
|
|
self.element(sp, name.as_str())
|
|
},
|
|
// Block
|
|
[TtDelimited(sp, ref d), ..] if d.delim == token::DelimToken::Brace => {
|
|
self.shift(1);
|
|
let stmts = self.block(sp, &d.tts);
|
|
self.render.push_stmts(stmts);
|
|
},
|
|
// ???
|
|
_ => {
|
|
if let [ref tt, ..] = self.input {
|
|
self.render.cx.span_err(tt.get_span(), "invalid syntax");
|
|
} else {
|
|
self.render.cx.span_err(self.span, "unexpected end of block");
|
|
}
|
|
return false;
|
|
},
|
|
}
|
|
true
|
|
}
|
|
|
|
fn literal(&mut self, tt: &TokenTree, minus: bool) {
|
|
let lit = self.new_rust_parser(vec![tt.clone()]).parse_lit();
|
|
match lit_to_string(self.render.cx, lit, minus) {
|
|
Some(s) => self.render.string(&s, Escape::Escape),
|
|
None => {},
|
|
}
|
|
}
|
|
|
|
fn splice(&mut self, sp: Span) -> P<Expr> {
|
|
let mut tts = vec![];
|
|
// First, munch a single token tree
|
|
if let [ref tt, ..] = self.input {
|
|
self.shift(1);
|
|
tts.push(tt.clone());
|
|
}
|
|
loop {
|
|
match self.input {
|
|
// Munch attribute lookups e.g. `$person.address.street`
|
|
[ref dot @ dot!(), ref ident @ ident!(_), ..] => {
|
|
self.shift(2);
|
|
tts.push(dot.clone());
|
|
tts.push(ident.clone());
|
|
},
|
|
// Munch function calls `()` and indexing operations `[]`
|
|
[TtDelimited(sp, ref d), ..] if d.delim != token::DelimToken::Brace => {
|
|
self.shift(1);
|
|
tts.push(TtDelimited(sp, d.clone()));
|
|
},
|
|
_ => break,
|
|
}
|
|
}
|
|
if tts.is_empty() {
|
|
self.render.cx.span_fatal(sp, "expected expression for this splice");
|
|
} else {
|
|
self.new_rust_parser(tts).parse_expr()
|
|
}
|
|
}
|
|
|
|
fn element(&mut self, sp: Span, name: &str) {
|
|
if self.in_attr {
|
|
self.render.cx.span_err(sp, "unexpected element, you silly bumpkin");
|
|
return;
|
|
}
|
|
self.render.element_open_start(name);
|
|
self.attrs();
|
|
self.render.element_open_end();
|
|
if let [slash!(), ..] = self.input {
|
|
self.shift(1);
|
|
} else {
|
|
self.markup();
|
|
self.render.element_close(name);
|
|
}
|
|
}
|
|
|
|
fn attrs(&mut self) {
|
|
loop { match self.input {
|
|
[ident!(name), eq!(), ..] => {
|
|
// Non-empty attribute
|
|
self.shift(2);
|
|
self.render.attribute_start(name.as_str());
|
|
{
|
|
// Parse a value under an attribute context
|
|
let in_attr = true;
|
|
mem::swap(&mut self.in_attr, &mut in_attr);
|
|
self.markup();
|
|
mem::swap(&mut self.in_attr, &mut in_attr);
|
|
}
|
|
self.render.attribute_end();
|
|
},
|
|
[ident!(name), question!(), ..] => {
|
|
// Empty attribute
|
|
self.shift(2);
|
|
if let [ref tt @ eq!(), ..] = self.input {
|
|
// Toggle the attribute based on a boolean expression
|
|
self.shift(1);
|
|
let cond = self.splice(tt.get_span());
|
|
// Silence "unnecessary parentheses" warnings
|
|
let cond = strip_outer_parens(cond);
|
|
let body = {
|
|
let mut r = self.render.fork();
|
|
r.attribute_empty(name.as_str());
|
|
r.into_stmts()
|
|
};
|
|
self.render.emit_if(cond, body, None);
|
|
} else {
|
|
// Write the attribute unconditionally
|
|
self.render.attribute_empty(name.as_str());
|
|
}
|
|
},
|
|
_ => return,
|
|
}}
|
|
}
|
|
|
|
fn block(&mut self, sp: Span, tts: &[TokenTree]) -> Vec<P<Stmt>> {
|
|
let mut parse = Parser {
|
|
in_attr: self.in_attr,
|
|
input: tts,
|
|
span: sp,
|
|
render: self.render.fork(),
|
|
};
|
|
parse.markups();
|
|
parse.into_render().into_stmts()
|
|
}
|
|
}
|
|
|
|
/// Convert a literal to a string.
|
|
fn lit_to_string(cx: &ExtCtxt, lit: Lit, minus: bool) -> Option<String> {
|
|
use syntax::ast::Lit_::*;
|
|
let mut result = String::new();
|
|
if minus {
|
|
result.push('-');
|
|
}
|
|
match lit.node {
|
|
LitStr(s, _) => result.push_str(&s),
|
|
LitBinary(..) | LitByte(..) => {
|
|
cx.span_err(lit.span, "cannot splice binary data");
|
|
return None;
|
|
},
|
|
LitChar(c) => result.push(c),
|
|
LitInt(x, _) => result.push_str(&x.to_string()),
|
|
LitFloat(s, _) | LitFloatUnsuffixed(s) => result.push_str(&s),
|
|
LitBool(b) => result.push_str(if b { "true" } else { "false" }),
|
|
};
|
|
Some(result)
|
|
}
|
|
|
|
/// If the expression is wrapped in parentheses, strip them off.
|
|
fn strip_outer_parens(expr: P<Expr>) -> P<Expr> {
|
|
expr.and_then(|expr| match expr {
|
|
Expr { node: ExprParen(inner), .. } => inner,
|
|
expr => P(expr),
|
|
})
|
|
}
|