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Refactor to keep up with changes to proc_macro

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Instead of a `kind` field containting a `TokenNode` variant, a
TokenTree is now an enum with variants of different types (Literal, Op,
Term, etc). Note that a TokenTree could be a sequence of TokenTrees if it is a
Group variant.

Other notes:

I'm unsure about the set_span call in Builder::emit_if, but I did not want to
throw away the passed in Span.

Parsing relies on destructuring references to the values associated with
TokenTree enum variants

It doesn't seem as easy to compose/chain TokenStreams as it is to
collect a Vec<TokenTree> into a TokenStream. There is probably some
iterator API I could use instead. See `match_arms` and build.rs

Refs
This commit is contained in:
Coleman McFarland 2018-04-06 18:13:42 -07:00
parent 3d22f90ad7
commit 0f453a5568
3 changed files with 139 additions and 127 deletions
maud_macros/src
build.rslib.rsparse.rs

33
maud_macros/src/build.rs
View file

@ -1,6 +1,5 @@
use proc_macro::{Delimiter, Literal, Span, TokenNode, TokenStream, TokenTree};
use proc_macro::{Delimiter, Group, Literal, Span, TokenStream, TokenTree};
use proc_macro::quote;
use maud_htmlescape::Escaper;
pub struct Builder {
@ -24,7 +23,7 @@ impl Builder {
if !self.tail.is_empty() {
let expr = {
let output_ident = self.output_ident.clone();
let string = TokenNode::Literal(Literal::string(&self.tail));
let string = TokenTree::Literal(Literal::string(&self.tail));
quote!($output_ident.push_str($string);)
};
self.stmts.push(expr);
@ -35,7 +34,15 @@ impl Builder {
/// Reifies the `Builder` into a raw list of statements.
pub fn build(mut self) -> TokenStream {
let Builder { stmts, .. } = { self.flush(); self };
stmts.into_iter().collect()
// use a Group here?
let mut tts: Vec<TokenTree> = Vec::new();
for s in stmts.into_iter() {
let i = s.into_iter();
tts.extend(i);
}
tts.into_iter().collect()
}
/// Pushes a statement, flushing the tail buffer in the process.
@ -111,14 +118,20 @@ impl Builder {
) {
// If the condition contains an opening brace `{`,
// wrap it in parentheses to avoid parse errors
if cond.clone().into_iter().any(|token| match token.kind {
TokenNode::Group(Delimiter::Brace, _) => true,
if cond.clone().into_iter().any(|token| match token {
TokenTree::Group(grp) => {
if grp.delimiter() == Delimiter::Brace {
true
} else {
false
}
},
_ => false,
}) {
cond = TokenStream::from(TokenTree {
kind: TokenNode::Group(Delimiter::Parenthesis, cond),
span: cond_span,
});
let mut g = Group::new(Delimiter::Parenthesis, cond);
// NOTE: Do we need to do this?
g.set_span(cond_span);
cond = TokenStream::from(TokenTree::Group(g));
}
self.push(quote!(if $cond { $body }));
}

17
maud_macros/src/lib.rs
View file

@ -1,4 +1,5 @@
#![feature(proc_macro)]
#![feature(pattern_parentheses)]
#![doc(html_root_url = "https://docs.rs/maud_macros/0.17.2")]
@ -9,7 +10,7 @@ extern crate proc_macro;
mod parse;
mod build;
use proc_macro::{Literal, Span, Term, TokenNode, TokenStream, TokenTree};
use proc_macro::{Span, Term, TokenStream, TokenTree};
use proc_macro::quote;
type ParseResult<T> = Result<T, String>;
@ -27,21 +28,21 @@ pub fn html_debug(input: TokenStream) -> TokenStream {
}
fn expand(input: TokenStream) -> TokenStream {
let output_ident = TokenTree {
kind: TokenNode::Term(Term::intern("__maud_output")),
span: Span::def_site(),
};
let output_ident = TokenTree::Term(Term::new("__maud_output", Span::def_site()));
// Heuristic: the size of the resulting markup tends to correlate with the
// code size of the template itself
let size_hint = input.to_string().len();
let size_hint = TokenNode::Literal(Literal::u64(size_hint as u64));
//
// NOTE: can't get this to compile inside quote!
//let size_hint = Literal::u64_unsuffixed(size_hint as u64);
let stmts = match parse::parse(input, output_ident.clone()) {
Ok(stmts) => stmts,
Err(e) => panic!(e),
};
quote!({
extern crate maud;
let mut $output_ident = String::with_capacity($size_hint as usize);
//let mut $output_ident = String::with_capacity($size_hint as usize);
let mut $output_ident = String::new();
$stmts
maud::PreEscaped($output_ident)
})

200
maud_macros/src/parse.rs
View file

@ -1,14 +1,15 @@
use proc_macro::{
Delimiter,
Group,
Literal,
Spacing,
Span,
TokenNode,
Term,
TokenStream,
TokenTree,
TokenTreeIter,
};
use std::iter;
use proc_macro::token_stream;
use std::mem;
use literalext::LiteralExt;
@ -28,7 +29,7 @@ struct Parser {
output_ident: TokenTree,
/// Indicates whether we're inside an attribute node.
in_attr: bool,
input: TokenTreeIter,
input: token_stream::IntoIter,
}
impl Iterator for Parser {
@ -97,24 +98,18 @@ impl Parser {
loop {
match self.peek2() {
None => return Ok(()),
Some((TokenTree { kind: TokenNode::Op(';', _), .. }, _)) => self.advance(),
Some((
TokenTree { kind: TokenNode::Op('@', _), .. },
Some(TokenTree { kind: TokenNode::Term(term), span }),
)) if term.as_str() == "let" => {
Some((TokenTree::Op(o), _)) if o.op() == ';' => self.advance(),
Some((TokenTree::Op(o), Some(TokenTree::Term(term)))) if o.op() == '@' && term.as_str() == "let" => {
// When emitting a `@let`, wrap the rest of the block in a
// new block to avoid scoping issues
let keyword = TokenTree { kind: TokenNode::Term(term), span };
let keyword = Term::new(term.as_str(), term.span());
self.advance2();
builder.push({
let mut builder = self.builder();
builder.push(keyword);
builder.push(TokenTree::Term(keyword));
self.let_expr(&mut builder)?;
self.markups(&mut builder)?;
TokenTree {
kind: TokenNode::Group(Delimiter::Brace, builder.build()),
span,
}
TokenTree::Group(Group::new(Delimiter::Brace, builder.build()))
});
},
_ => self.markup(builder)?,
@ -130,17 +125,17 @@ impl Parser {
};
match token {
// Literal
TokenTree { kind: TokenNode::Literal(lit), .. } => {
TokenTree::Literal(lit) => {
self.advance();
self.literal(lit, builder)?;
},
// Special form
TokenTree { kind: TokenNode::Op('@', _), .. } => {
TokenTree::Op(o) if o.op() == '@' => {
self.advance();
match self.next() {
Some(TokenTree { kind: TokenNode::Term(term), span }) => {
let keyword = TokenTree { kind: TokenNode::Term(term), span };
builder.push(keyword);
Some(TokenTree::Term(term)) => {
let keyword = Term::new(term.as_str(), term.span());
builder.push(TokenTree::Term(keyword));
match term.as_str() {
"if" => self.if_expr(builder)?,
"while" => self.while_expr(builder)?,
@ -152,21 +147,21 @@ impl Parser {
},
_ => return self.error("expected keyword after `@`"),
}
}
},
// Element
TokenTree { kind: TokenNode::Term(_), .. } => {
TokenTree::Term(_) => {
let name = self.namespaced_name()?;
self.element(&name, builder)?;
},
// Splice
TokenTree { kind: TokenNode::Group(Delimiter::Parenthesis, expr), .. } => {
TokenTree::Group(ref grp) if grp.delimiter() == Delimiter::Parenthesis => {
self.advance();
builder.splice(expr);
}
builder.splice(grp.stream());
},
// Block
TokenTree { kind: TokenNode::Group(Delimiter::Brace, block), .. } => {
TokenTree::Group(ref grp) if grp.delimiter() == Delimiter::Brace => {
self.advance();
self.with_input(block).markups(builder)?;
self.with_input(grp.stream()).markups(builder)?;
},
// ???
_ => return self.error("invalid syntax"),
@ -190,8 +185,9 @@ impl Parser {
fn if_expr(&mut self, builder: &mut Builder) -> ParseResult<()> {
loop {
match self.next() {
Some(TokenTree { kind: TokenNode::Group(Delimiter::Brace, block), span }) => {
let block = self.block(block, span)?;
Some(TokenTree::Group(ref block))
if block.delimiter() == Delimiter::Brace => {
let block = self.block(block.stream(), block.span())?;
builder.push(block);
break;
},
@ -207,30 +203,28 @@ impl Parser {
/// The leading `@else if` or `@else` should *not* already be consumed.
fn else_if_expr(&mut self, builder: &mut Builder) -> ParseResult<()> {
match self.peek2() {
// Try to match an `@else` after this
Some((
TokenTree { kind: TokenNode::Op('@', _), .. },
Some(TokenTree { kind: TokenNode::Term(else_keyword), span }),
)) if else_keyword.as_str() == "else" => {
Some((TokenTree::Op(o), Some(TokenTree::Term(else_keyword))))
if o.op() == '@' && else_keyword.as_str() == "else" => {
self.advance2();
let else_keyword = TokenTree { kind: TokenNode::Term(else_keyword), span };
builder.push(else_keyword);
let else_keyword = Term::new("else", else_keyword.span());
builder.push(TokenTree::Term(else_keyword));
match self.peek() {
// `@else if`
Some(TokenTree { kind: TokenNode::Term(if_keyword), span })
if if_keyword.as_str() == "if" => {
Some(TokenTree::Term(if_keyword)) if if_keyword.as_str() == "if" => {
self.advance();
let if_keyword = TokenTree { kind: TokenNode::Term(if_keyword), span };
builder.push(if_keyword);
let if_keyword = Term::new("if", if_keyword.span());
builder.push(TokenTree::Term(if_keyword));
self.if_expr(builder)?;
},
// Just an `@else`
_ => {
if let Some(TokenTree { kind: TokenNode::Group(Delimiter::Brace, block), span }) = self.next() {
let block = self.block(block, span)?;
// match brace `{`
match self.next() {
Some(TokenTree::Group(ref grp)) if grp.delimiter() == Delimiter::Brace => {
let block = self.block(grp.stream(), grp.span())?;
builder.push(block);
} else {
return self.error("expected body for @else");
},
_ => { return self.error("expected body for @else"); },
}
},
}
@ -247,8 +241,8 @@ impl Parser {
fn while_expr(&mut self, builder: &mut Builder) -> ParseResult<()> {
loop {
match self.next() {
Some(TokenTree { kind: TokenNode::Group(Delimiter::Brace, block), span }) => {
let block = self.block(block, span)?;
Some(TokenTree::Group(ref block)) if block.delimiter() == Delimiter::Brace => {
let block = self.block(block.stream(), block.span())?;
builder.push(block);
break;
},
@ -265,8 +259,9 @@ impl Parser {
fn for_expr(&mut self, builder: &mut Builder) -> ParseResult<()> {
loop {
match self.next() {
Some(TokenTree { kind: TokenNode::Term(in_keyword), span }) if in_keyword.as_str() == "in" => {
builder.push(TokenTree { kind: TokenNode::Term(in_keyword), span });
Some(TokenTree::Term(in_keyword)) if in_keyword.as_str() == "in" => {
let in_keyword = Term::new("in", in_keyword.span());
builder.push(TokenTree::Term(in_keyword));
break;
},
Some(token) => builder.push(token),
@ -275,8 +270,8 @@ impl Parser {
}
loop {
match self.next() {
Some(TokenTree { kind: TokenNode::Group(Delimiter::Brace, block), span }) => {
let block = self.block(block, span)?;
Some(TokenTree::Group(ref block)) if block.delimiter() == Delimiter::Brace => {
let block = self.block(block.stream(), block.span())?;
builder.push(block);
break;
},
@ -293,12 +288,10 @@ impl Parser {
fn match_expr(&mut self, builder: &mut Builder) -> ParseResult<()> {
loop {
match self.next() {
Some(TokenTree { kind: TokenNode::Group(Delimiter::Brace, body), span }) => {
let body = self.with_input(body).match_arms()?;
builder.push(TokenTree {
kind: TokenNode::Group(Delimiter::Brace, body),
span,
});
Some(TokenTree::Group(ref body)) if body.delimiter() == Delimiter::Brace => {
let body = self.with_input(body.stream()).match_arms()?;
let body = Group::new(Delimiter::Brace, body);
builder.push(TokenTree::Group(body));
break;
},
Some(token) => builder.push(token),
@ -309,24 +302,22 @@ impl Parser {
}
fn match_arms(&mut self) -> ParseResult<TokenStream> {
let mut arms = Vec::new();
let mut arms: Vec<TokenTree> = Vec::new();
while let Some(arm) = self.match_arm()? {
arms.push(arm);
arms.extend(arm);
}
Ok(arms.into_iter().collect())
}
fn match_arm(&mut self) -> ParseResult<Option<TokenStream>> {
let mut pat = Vec::new();
fn match_arm(&mut self) -> ParseResult<Option<Vec<TokenTree>>> {
let mut pat: Vec<TokenTree> = Vec::new();
loop {
match self.peek2() {
Some((
eq @ TokenTree { kind: TokenNode::Op('=', Spacing::Joint), .. },
Some(gt @ TokenTree { kind: TokenNode::Op('>', _), .. }),
)) => {
Some((TokenTree::Op(eq), Some(TokenTree::Op(gt))))
if eq.op() == '=' && gt.op() == '>' && eq.spacing() == Spacing::Joint => {
self.advance2();
pat.push(eq);
pat.push(gt);
pat.push(TokenTree::Op(eq));
pat.push(TokenTree::Op(gt));
break;
},
Some((token, _)) => {
@ -343,23 +334,25 @@ impl Parser {
}
let body = match self.next() {
// $pat => { $stmts }
Some(TokenTree { kind: TokenNode::Group(Delimiter::Brace, body), span }) => {
let body = self.block(body, span)?;
Some(TokenTree::Group(ref body)) if body.delimiter() == Delimiter::Brace => {
let body: TokenTree = self.block(body.stream(), body.span())?;
// Trailing commas are optional if the match arm is a braced block
if let Some(TokenTree { kind: TokenNode::Op(',', _), .. }) = self.peek() {
if let Some(TokenTree::Op(o)) = self.peek() {
if o.op() == ',' {
self.advance();
}
}
body
},
// $pat => $expr
Some(first_token) => {
let mut span = first_token.span;
let mut span = first_token.span();
let mut body = vec![first_token];
loop {
match self.next() {
Some(TokenTree { kind: TokenNode::Op(',', _), .. }) => break,
Some(TokenTree::Op(o)) if o.op() == ',' => break,
Some(token) => {
if let Some(bigger_span) = span.join(token.span) {
if let Some(bigger_span) = span.join(token.span()) {
span = bigger_span;
}
body.push(token);
@ -371,7 +364,8 @@ impl Parser {
},
None => return self.error("unexpected end of @match arm"),
};
Ok(Some(pat.into_iter().chain(iter::once(body)).collect()))
pat.push(body);
Ok(Some(pat))
}
/// Parses and renders a `@let` expression.
@ -380,21 +374,29 @@ impl Parser {
fn let_expr(&mut self, builder: &mut Builder) -> ParseResult<()> {
loop {
match self.next() {
Some(token @ TokenTree { kind: TokenNode::Op('=', _), .. }) => {
builder.push(token);
Some(token) => {
match token {
TokenTree::Op(ref o) if o.op() == '=' => {
builder.push(token.clone());
break;
}
_ => builder.push(token),
}
},
Some(token) => builder.push(token),
None => return self.error("unexpected end of @let expression"),
}
}
loop {
match self.next() {
Some(token @ TokenTree { kind: TokenNode::Op(';', _), .. }) => {
builder.push(token);
Some(token) => {
match token {
TokenTree::Op(ref o) if o.op() == ';' => {
builder.push(token.clone());
break;
},
Some(token) => builder.push(token),
_ => builder.push(token),
}
},
None => return self.error("unexpected end of @let expression"),
}
}
@ -412,8 +414,7 @@ impl Parser {
self.attrs(builder)?;
builder.element_open_end();
match self.peek() {
Some(TokenTree { kind: TokenNode::Op(';', _), .. }) |
Some(TokenTree { kind: TokenNode::Op('/', _), .. }) => {
Some(TokenTree::Op(o)) if o.op() == ';' || o.op() == '/' => {
// Void element
self.advance();
},
@ -436,7 +437,7 @@ impl Parser {
let token_after = attempt.next();
match (maybe_name, token_after) {
// Non-empty attribute
(Ok(name), Some(TokenTree { kind: TokenNode::Op('=', _), .. })) => {
(Ok(ref name), Some(TokenTree::Op(ref o))) if o.op() == '=' => {
self.commit(attempt);
builder.attribute_start(&name);
{
@ -448,7 +449,7 @@ impl Parser {
builder.attribute_end();
},
// Empty attribute
(Ok(name), Some(TokenTree { kind: TokenNode::Op('?', _), .. })) => {
(Ok(ref name), Some(TokenTree::Op(ref o))) if o.op() == '?' => {
self.commit(attempt);
if let Some((cond, cond_span)) = self.attr_toggler() {
// Toggle the attribute based on a boolean expression
@ -464,7 +465,7 @@ impl Parser {
}
},
// Class shorthand
(Err(_), Some(TokenTree { kind: TokenNode::Op('.', _), .. })) => {
(Err(_), Some(TokenTree::Op(o))) if o.op() == '.' => {
self.commit(attempt);
let class_name = self.name()?;
if let Some((cond, cond_span)) = self.attr_toggler() {
@ -476,7 +477,7 @@ impl Parser {
}
},
// ID shorthand
(Err(_), Some(TokenTree { kind: TokenNode::Op('#', _), .. })) => {
(Err(_), Some(TokenTree::Op(o))) if o.op() == '#' => {
self.commit(attempt);
ids.push(self.name()?);
},
@ -512,20 +513,18 @@ impl Parser {
/// Parses the `[cond]` syntax after an empty attribute or class shorthand.
fn attr_toggler(&mut self) -> Option<(TokenStream, Span)> {
if let Some(TokenTree {
kind: TokenNode::Group(Delimiter::Bracket, cond),
span: delim_span,
}) = self.peek() {
match self.peek() {
Some(TokenTree::Group(ref grp)) if grp.delimiter() == Delimiter::Bracket => {
self.advance();
Some((cond, delim_span))
} else {
None
Some((grp.stream(), grp.span()))
}
_ => None
}
}
/// Parses an identifier, without dealing with namespaces.
fn name(&mut self) -> ParseResult<String> {
let mut s = if let Some(TokenTree { kind: TokenNode::Term(term), .. }) = self.peek() {
let mut s = if let Some(TokenTree::Term(term)) = self.peek() {
self.advance();
String::from(term.as_str())
} else {
@ -534,12 +533,12 @@ impl Parser {
let mut expect_ident = false;
loop {
expect_ident = match self.peek() {
Some(TokenTree { kind: TokenNode::Op('-', _), .. }) => {
Some(TokenTree::Op(o)) if o.op() == '-' => {
self.advance();
s.push('-');
true
},
Some(TokenTree { kind: TokenNode::Term(term), .. }) if expect_ident => {
Some(TokenTree::Term(term)) if expect_ident => {
self.advance();
s.push_str(term.as_str());
false
@ -554,22 +553,21 @@ impl Parser {
/// if necessary.
fn namespaced_name(&mut self) -> ParseResult<String> {
let mut s = self.name()?;
if let Some(TokenTree { kind: TokenNode::Op(':', _), .. }) = self.peek() {
if let Some(TokenTree::Op(o)) = self.peek() {
if o.op() == ':' {
self.advance();
s.push(':');
s.push_str(&self.name()?);
}
}
Ok(s)
}
/// Parses the given token stream as a Maud expression, returning a block of
/// Rust code.
fn block(&mut self, body: TokenStream, span: Span) -> ParseResult<TokenTree> {
fn block(&mut self, body: TokenStream, _span: Span) -> ParseResult<TokenTree> {
let mut builder = self.builder();
self.with_input(body).markups(&mut builder)?;
Ok(TokenTree {
kind: TokenNode::Group(Delimiter::Brace, builder.build()),
span,
})
Ok(TokenTree::Group(Group::new(Delimiter::Brace, builder.build())))
}
}