rowan_peg/
lib.rs

1use core::fmt;
2use std::{collections::HashSet, fmt::Display, mem::take};
3use char_classes::any;
4use linked_hash_map::LinkedHashMap as HashMap;
5
6use rowan::ast::AstNode;
7use to_true::{InTrue, ToTrue};
8use unicode_ident::{is_xid_continue, is_xid_start};
9use rowan_peg_utils::match_options;
10
11use crate::utils::UsedBound;
12
13mod utils;
14mod bootstarp;
15
16pub use bootstarp::*;
17
18impl Repeat {
19    pub fn count_bounds(&self) -> (u32, Option<u32>) {
20        if self.plus().is_some() {
21            (1, None)
22        } else if let Some(rest) = self.repeat_rest() {
23            let lower_bound = self.number().as_ref().map_or(0, value::number);
24            let upper_bound = rest.number().as_ref().map(value::number);
25            (lower_bound, upper_bound)
26        } else if let Some(number) = self.number() {
27            let bound = value::number(&number);
28            (bound, bound.into())
29        } else {
30            unreachable!()
31        }
32    }
33}
34
35pub mod value {
36    use crate::{SyntaxKind as Kind, Label, SyntaxToken};
37
38    #[track_caller]
39    pub fn string(s: &SyntaxToken) -> &str {
40        debug_assert_eq!(s.kind(), Kind::STRING);
41        let s = s.text();
42        &s[1..s.len()-1]
43    }
44
45    #[track_caller]
46    pub fn matches(s: &SyntaxToken) -> &str {
47        debug_assert_eq!(s.kind(), Kind::MATCHES);
48        let s = s.text();
49        &s[1..s.len()-1]
50    }
51
52    #[track_caller]
53    pub fn label(l: &Label) -> String {
54        l.ident()
55            .map(|ident| ident.text().to_owned())
56            .unwrap_or_else(|| string(&l.string().unwrap()).to_owned())
57    }
58
59    pub fn number(s: &SyntaxToken) -> u32 {
60        debug_assert_eq!(s.kind(), Kind::NUMBER);
61        s.text().parse().unwrap()
62    }
63}
64
65#[derive(Debug)]
66pub enum Error {
67    EmptyLiteral(SyntaxToken),
68    UnknownLiteral(SyntaxToken),
69    MatchesWithoutSlice(SyntaxToken),
70    DisallowedSlice(SyntaxNode),
71}
72
73impl Display for Error {
74    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
75        match self {
76            Error::EmptyLiteral(t) => {
77                write!(f, "empty literal {:?}", t.text())
78            },
79            Error::UnknownLiteral(t) => {
80                write!(f, "unknown literal {:?}", t.text())
81            },
82            Error::MatchesWithoutSlice(t) => {
83                write!(f, "matches without slice {:?}", t.text())
84            },
85            Error::DisallowedSlice(t) => {
86                write!(f, "disallowed slice {:?}", t.text())
87            },
88        }
89    }
90}
91
92type Result<T, E = Error> = core::result::Result<T, E>;
93
94#[derive(Debug, PartialEq, Eq)]
95enum Method {
96    Optional,
97    Strict,
98    Many,
99}
100
101#[derive(Debug, PartialEq, Eq)]
102struct DeclMeta {
103    methods: Vec<(String, Method)>,
104    docs: String,
105}
106
107pub struct Processor<W: fmt::Write> {
108    out: W,
109    kind_names_map: HashMap<String, String>,
110    slice: u32,
111    is_token_decl: bool,
112    exports: HashMap<String, String>,
113    decl_name: String,
114    refs_bound: HashMap<String, UsedBound>,
115    is_tokens: HashSet<String>,
116    decls: HashMap<String, DeclMeta>,
117}
118
119impl<W: fmt::Write> From<W> for Processor<W> {
120    fn from(out: W) -> Self {
121        Self {
122            out,
123            kind_names_map: HashMap::new(),
124            slice: 0,
125            is_token_decl: false,
126            exports: HashMap::new(),
127            decl_name: String::new(),
128            refs_bound: HashMap::new(),
129            is_tokens: HashSet::new(),
130            decls: HashMap::new(),
131        }
132    }
133}
134
135const PRE_DEFINE_ITEMS: &str = {
136r#"// Generated by rowan-peg, do not edit it
137use rowan::{ast::{support, AstChildren, AstNode}, Language};
138
139macro_rules! decl_ast_node {
140    ($node:ident, $kind:ident $(, #[$meta:meta])?) => {
141        $(#[$meta])?
142        #[derive(Debug, Clone, PartialEq, Eq, Hash)]
143        pub struct $node(SyntaxNode);
144        impl AstNode for $node {
145            type Language = Lang;
146
147            fn syntax(&self) -> &rowan::SyntaxNode<Self::Language> {
148                &self.0
149            }
150
151            fn can_cast(kind: <Self::Language as Language>::Kind) -> bool {
152                kind == SyntaxKind::$kind
153            }
154
155            fn cast(node: rowan::SyntaxNode<Self::Language>) -> Option<Self> {
156                if Self::can_cast(node.kind()) {
157                    Some(Self(node))
158                } else {
159                    None
160                }
161            }
162        }
163        impl core::fmt::Display for $node {
164            fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
165                core::fmt::Display::fmt(self.syntax(), f)
166            }
167        }
168    };
169}
170
171#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
172pub enum Lang {}
173impl Language for Lang {
174    type Kind = SyntaxKind;
175
176    fn kind_to_raw(kind: Self::Kind) -> ::rowan::SyntaxKind {
177        kind.into()
178    }
179
180    fn kind_from_raw(raw: ::rowan::SyntaxKind) -> Self::Kind {
181        raw.into()
182    }
183}
184
185pub type SyntaxNode = ::rowan::SyntaxNode<Lang>;
186pub type SyntaxToken = ::rowan::SyntaxToken<Lang>;
187"#};
188const PRE_DEFINE_RULES: &str = r#""#;
189
190impl<W: fmt::Write> Processor<W> {
191    fn gen_tok_wrap<F, R>(&mut self, kind: &str, f: F) -> R
192    where F: FnOnce(&mut Self) -> R,
193    {
194        write!(self.out, "(g:({{state.quiet().guard_token({kind})}}) s:$((").unwrap();
195        let result = f(self);
196        write!(self.out, ")) {{g.accept_token(s)}})").unwrap();
197        result
198    }
199
200    fn gen_node_wrap<F, R>(&mut self, kind: &str, f: F) -> R
201    where F: FnOnce(&mut Self) -> R,
202    {
203        write!(self.out, "(g:({{state.guard({kind})}}) (").unwrap();
204        let result = f(self);
205        write!(self.out, ") {{g.accept()}})").unwrap();
206        result
207    }
208
209    fn gen_quiet_wrap<F, R>(&mut self, f: F) -> R
210    where F: FnOnce(&mut Self) -> R,
211    {
212        write!(self.out, "(g:({{state.quiet().guard_none()}}) (quiet!{{").unwrap();
213        let result = f(self);
214        write!(self.out, "}}) {{g.accept_none()}})").unwrap();
215        result
216    }
217
218    fn gen_back_wrap<F, R>(&mut self, f: F) -> R
219    where F: FnOnce(&mut Self) -> R,
220    {
221        write!(self.out, "(g:({{state.guard_none()}})(").unwrap();
222        let result = f(self);
223        write!(self.out, "){{g.accept_none()}})").unwrap();
224        result
225    }
226
227    fn regist_name(&mut self, name: &str) -> (String, String) {
228        let name = utils::rule_name_of(name);
229        let kind_name = self.kind_names_map.entry(name.to_owned())
230            .or_insert_with(|| utils::kind_name_of(self.exports.get(&name).unwrap_or(&name)));
231        (name, kind_name.clone())
232    }
233
234    fn regist_tok_name(&mut self, token: &SyntaxToken) -> Result<(String, String)> {
235        let content = if token.kind() == SyntaxKind::STRING { value::string(token) } else { value::matches(token) };
236        if content.is_empty() {
237            return Err(Error::EmptyLiteral(token.clone()));
238        }
239        let (name, kind_name) = if let Some(name) = utils::punct_name_of(content) {
240            (name.to_owned(), utils::kind_name_of(&name))
241        } else if is_xid_start(content.chars().next().unwrap())
242            && content.chars().all(|ch| matches!(ch, '-' | '_') || is_xid_continue(ch))
243        {
244            let name = utils::rule_name_of(&format!("{content}_kw"));
245            let kind_name = utils::kind_name_of(&name);
246            (name, kind_name)
247        } else {
248            return Err(Error::UnknownLiteral(token.to_owned()));
249        };
250
251        self.is_tokens.insert(name.clone());
252        self.kind_names_map.insert(name.clone(), kind_name.clone());
253
254        Ok((name, kind_name))
255    }
256
257    fn add_bound(&mut self, name: impl Into<String>) {
258        if !self.is_token_decl {
259            let mut name = name.into();
260            if let Some(renamed_name) = self.exports.get(&name) {
261                name = renamed_name.to_owned();
262            }
263            *self.refs_bound.entry(name).or_default() += 1;
264        }
265    }
266
267    fn dis_refs_bound<T>(&mut self, f: impl FnOnce(&mut Self) -> T) -> T {
268        let refs_bound = self.take_refs_bound();
269        let result = f(self);
270        self.refs_bound = refs_bound;
271        result
272    }
273
274    #[must_use]
275    fn take_refs_bound(&mut self) -> HashMap<String, UsedBound> {
276        take(&mut self.refs_bound)
277    }
278
279    pub fn start_process(&mut self, decl_list: &DeclList) -> Result<()> {
280        for export in decl_list.export_list().iter().flat_map(|list| list.exports()) {
281            let name = export.ident();
282            let new_name = export.named()
283                .map_or(name.clone(), |it| it.ident());
284            self.exports.insert(
285                utils::rule_name_of(name.text()),
286                utils::rule_name_of(new_name.text()),
287            );
288        }
289
290        writeln!(self.out, "{PRE_DEFINE_ITEMS}").unwrap();
291        writeln!(self.out, "::peg::parser!(pub grammar parser<'b>(state: \
292            &'b ::rowan_peg_utils::ParseState<'input>) for str {{").unwrap();
293        writeln!(self.out, "    use SyntaxKind::*;").unwrap();
294        writeln!(self.out, "{PRE_DEFINE_RULES}").unwrap();
295        for decl in decl_list.decls() {
296            self.process_decl(decl)?;
297        }
298        writeln!(self.out, "}});").unwrap();
299        writeln!(self.out, "#[repr(u16)]").unwrap();
300        writeln!(self.out, "#[allow(non_camel_case_types)]").unwrap();
301        writeln!(self.out, "#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]").unwrap();
302        writeln!(self.out, "pub enum SyntaxKind {{").unwrap();
303        let mut first = true;
304        let mut last = None;
305        for kind in self.kind_names_map.values() {
306            first.to_false(|| {
307                writeln!(self.out, "    {kind} = 0,").unwrap();
308            }).unwrap_or_else(|| {
309                writeln!(self.out, "    {kind},").unwrap();
310            });
311            last = kind.into();
312        }
313        writeln!(self.out, "}}").unwrap();
314        writeln!(self.out, "impl From<::rowan::SyntaxKind> for SyntaxKind {{ \
315            fn from(kind: ::rowan::SyntaxKind) -> Self {{ \
316                ::core::assert!(kind.0 <= Self::{} as u16); \
317                unsafe {{ ::core::mem::transmute::<u16, SyntaxKind>(kind.0) }} \
318            }} \
319        }}", last.unwrap()).unwrap();
320        writeln!(self.out, "impl From<SyntaxKind> for ::rowan::SyntaxKind {{ \
321            fn from(kind: SyntaxKind) -> Self {{ \
322                ::rowan::SyntaxKind(kind as u16) \
323            }} \
324        }}").unwrap();
325        for (rule_name, mut meta) in self.decls.drain() {
326            if self.is_tokens.contains(&rule_name) { continue }
327            let node_name = utils::node_name_of(&rule_name);
328            let node_kind = utils::kind_name_of(&rule_name);
329            meta.methods.sort_by(|a, b| a.0.cmp(&b.0));
330
331            writeln!(self.out, "decl_ast_node!(\
332                    {node_name}, \
333                    {node_kind}, \
334                    #[doc = {:?}]\
335                    );",
336                    meta.docs,
337            ).unwrap();
338            writeln!(self.out, "impl {node_name} {{").unwrap();
339            for (child_name, method) in meta.methods {
340                let is_token = self.is_tokens.contains(&child_name);
341                let mut base_ty = if is_token {
342                    "SyntaxToken".to_owned()
343                } else {
344                    utils::node_name_of(&child_name)
345                };
346                base_ty = match method {
347                    Method::Optional => format!("Option<{base_ty}>"),
348                    Method::Strict => base_ty,
349                    Method::Many if is_token => "impl Iterator<Item = SyntaxToken>".into(),
350                    Method::Many => format!("AstChildren<{base_ty}>"),
351                };
352                let body = if is_token {
353                    let kind = utils::kind_name_of(&child_name);
354                    match method {
355                        Method::Optional => format!("support::token(self.syntax(), SyntaxKind::{kind})"),
356                        Method::Strict => format!("support::token(self.syntax(), SyntaxKind::{kind}).unwrap()"),
357                        Method::Many => format!("::rowan_peg_utils::tokens(self.syntax(), SyntaxKind::{kind})"),
358                    }
359                } else {
360                    match method {
361                        Method::Optional => "support::child(self.syntax())",
362                        Method::Strict => "support::child(self.syntax()).unwrap()",
363                        Method::Many => "support::children(self.syntax())",
364                    }.into()
365                };
366                let method_name = if method == Method::Many {
367                    if is_token {
368                        format!("{child_name}_tokens")
369                    } else if child_name.ends_with('s') {
370                        format!("{child_name}es")
371                    } else {
372                        format!("{child_name}s")
373                    }
374                } else {
375                    child_name.clone()
376                };
377                if let Some(punct) = utils::punct_of(&child_name)
378                    && punct.trim() == punct
379                {
380                    let hint = child_name.replace('_', " ");
381                    if punct.contains('`') {
382                        writeln!(self.out, r#"    /// Get {hint} `` {punct} ``"#).unwrap();
383                    } else {
384                        writeln!(self.out, r#"    /// Get {hint} `{punct}`"#).unwrap();
385                    }
386                    if !punct.chars().any(any!("'\" \t\r\n_\\")) {
387                        writeln!(self.out, r#"    #[doc(alias = {punct:?})]"#).unwrap();
388                    }
389                }
390                writeln!(self.out, "    pub fn {method_name}(&self) -> {base_ty} {{").unwrap();
391                writeln!(self.out, "        {body}").unwrap();
392                writeln!(self.out, "    }}").unwrap();
393            }
394            writeln!(self.out, "}}").unwrap();
395        }
396        Ok(())
397    }
398
399    fn decl_is_token(&self, decl: &Decl) -> bool {
400        let Some(list) = utils::one_elem(decl.pat_choice().pat_lists()) else { return false };
401        let Some(op) = utils::one_elem(list.pat_ops()) else { return false };
402        if op.dollar().is_some() {
403            return true;
404        }
405        op.pat_atom().syntax().text_range() != op.syntax().text_range()
406            && op.pat_atom().string().is_some()
407    }
408
409    fn process_decl(&mut self, decl: Decl) -> Result<()> {
410        let (name, kind_name) = self.regist_name(decl.named().ident().text());
411        self.is_token_decl = self.decl_is_token(&decl);
412        self.decl_name = name;
413        let name = &self.decl_name;
414        let mut vis = "";
415
416        if self.is_token_decl {
417            self.is_tokens.insert(name.clone());
418        }
419        if let Some(new_name) = self.exports.get(name) {
420            if name == new_name {
421                vis = "pub ";
422            } else {
423                writeln!(self.out, "    pub rule {new_name}() = {name}").unwrap();
424            }
425        }
426
427        self.refs_bound.clear();
428        write!(self.out, "    {vis}rule {name}() = ").unwrap();
429        if self.is_token_decl {
430            write!(self.out, "()").unwrap();
431            self.process_pat_choice(decl.pat_choice())?;
432        } else {
433            self.gen_node_wrap(&kind_name, |this| {
434                this.process_pat_choice(decl.pat_choice())
435            })?;
436        }
437
438        writeln!(self.out).unwrap();
439        let methods = self.refs_bound.iter().filter_map(|(name, bound)| {
440            let ty = match bound {
441                UsedBound(0, 0) => return None,
442                UsedBound(0, 1) => Method::Optional,
443                UsedBound(1, 1) => Method::Strict,
444                _ => Method::Many,
445            };
446            Some((name.clone(), ty))
447        }).collect();
448        let name = self.exports.get(&self.decl_name).unwrap_or(&self.decl_name);
449        self.decls.insert(name.clone(), DeclMeta {
450            methods,
451            docs: format!("```abnf\n{decl}\n```"),
452        });
453        Ok(())
454    }
455
456    fn process_pat_choice(&mut self, patchoice: PatChoice) -> Result<()> {
457        let mut first = true;
458        let refs_bound = self.take_refs_bound();
459        let mut prev_bound: Option<HashMap<String, UsedBound>> = None;
460        write!(self.out, "(").unwrap();
461        for patlist in patchoice.pat_lists() {
462            first.in_false(|| write!(self.out, " / ").unwrap());
463            write!(self.out, "()").unwrap();
464            self.gen_back_wrap(|this| this.process_pat_list(patlist))?;
465            if let Some(prev_bound) = &mut prev_bound {
466                self.merge_cover_to(prev_bound);
467            } else {
468                prev_bound = Some(self.take_refs_bound());
469            }
470        }
471        assert_eq!(self.refs_bound.len(), 0);
472        self.merge_add(refs_bound);
473        self.merge_add(prev_bound.unwrap());
474        if let Some(expected) = patchoice.pat_expect() {
475            let name = value::label(&expected.label());
476            write!(self.out, " / expected!({name:?})").unwrap();
477        }
478        write!(self.out, ")").unwrap();
479        Ok(())
480    }
481
482    fn merge_cover_to(&mut self, prev_bound: &mut HashMap<String, UsedBound>) {
483        for key in self.refs_bound.keys() {
484            if !prev_bound.contains_key(key) {
485                prev_bound.insert(key.clone(), UsedBound::default());
486            }
487        }
488        for (key, value) in &mut *prev_bound {
489            let other = self.refs_bound.get(key).copied().unwrap_or_default();
490            *value = value.cover(other);
491        }
492        self.refs_bound.clear();
493    }
494
495    fn merge_add(&mut self, refs_bound: HashMap<String, UsedBound>) {
496        for (key, value) in refs_bound {
497            *self.refs_bound.entry(key).or_default() += value;
498        }
499    }
500
501    fn process_pat_list(&mut self, patlist: PatList) -> Result<()> {
502        let mut first = true;
503        for patop in patlist.pat_ops() {
504            first.in_false(|| write!(self.out, " ").unwrap());
505            self.process_patop(patop)?;
506        }
507        Ok(())
508    }
509
510    fn process_patop(&mut self, patop: PatOp) -> Result<()> {
511        let atom = patop.pat_atom();
512        if patop.amp().is_some() {
513            write!(self.out, "&").unwrap();
514            self.gen_quiet_wrap(|this| this.dis_refs_bound(|this| this.process_patatom(atom)))?;
515        } else if patop.bang().is_some() {
516            write!(self.out, "!").unwrap();
517            self.gen_quiet_wrap(|this| this.dis_refs_bound(|this| this.process_patatom(atom)))?;
518        } else if patop.tilde().is_some() {
519            write!(self.out, "quiet!{{").unwrap();
520            self.dis_refs_bound(|this| this.process_patatom(atom))?;
521            write!(self.out, "}}").unwrap();
522        } else if patop.dollar().is_some() {
523            if self.is_token_decl && self.slice == 0 {
524                let name = &self.decl_name.clone();
525                let (_, kind_name) = self.regist_name(name);
526                self.slice += 1;
527                self.gen_tok_wrap(&kind_name, |this| {
528                    this.dis_refs_bound(|this| this.process_patatom(atom))
529                })?;
530                self.slice -= 1;
531            } else {
532                return Err(Error::DisallowedSlice(patop.syntax().clone()));
533            }
534        } else if let Some(repeat) = patop.repeat() {
535            let refs_bound = self.take_refs_bound();
536            self.gen_back_wrap(|this| this.process_patatom(atom))?;
537            let (lower_bound, upper_bound) = repeat.count_bounds();
538            match (lower_bound, upper_bound) {
539                (1, None) => write!(self.out, "+"),
540                (0, None) => write!(self.out, "*"),
541                (lower, None) => write!(self.out, "*<{lower},>"),
542                (lower, Some(upper)) => write!(self.out, "*<{lower},{upper}>"),
543            }.unwrap();
544            let repeat_meta = UsedBound(
545                lower_bound.try_into().unwrap(),
546                upper_bound.unwrap_or(255).try_into().unwrap(),
547            );
548            self.refs_bound.iter_mut().for_each(|(_, bound)| *bound *= repeat_meta);
549            self.merge_add(refs_bound);
550        } else {
551            self.process_patatom(atom)?;
552        }
553        Ok(())
554    }
555
556    fn process_patatom(&mut self, atom: PatAtom) -> Result<()> {
557        match_options! {match atom {
558            l_paren as _ => self.process_pat_choice(atom.pat_choice().unwrap())?,
559            l_brack as _ => {
560                let refs_bound = self.take_refs_bound();
561                self.gen_back_wrap(|this| this.process_pat_choice(atom.pat_choice().unwrap()))?;
562                write!(self.out, "?").unwrap();
563                self.refs_bound.iter_mut().for_each(|(_, bound)| bound.0 = 0);
564                self.merge_add(refs_bound);
565            },
566            ident => {
567                let name = utils::rule_name_of(ident.text());
568                write!(self.out, "{}()", name).unwrap();
569                self.add_bound(name);
570            },
571            string => self.tok_or_in_slice(&string)?,
572            matches if value::matches(&matches).chars().count() == 1 => {
573                // special unit string
574                self.tok_or_in_slice(&matches)?;
575            },
576            matches => {
577                if self.slice == 0 {
578                    return Err(Error::MatchesWithoutSlice(matches));
579                }
580                let content = value::matches(&matches);
581                write!(self.out, "(quiet!{{").unwrap();
582                if let Some(pat) = content.strip_prefix('^') {
583                    write!(self.out, "[^::char_classes::any!(@\"{pat}\")]").unwrap();
584                } else {
585                    write!(self.out, "[::char_classes::any!(@\"{content}\")]").unwrap();
586                }
587                write!(self.out, "}}/expected!({:?}))", matches.text()).unwrap();
588            },
589            _ => unreachable!(),
590        }}
591        Ok(())
592    }
593
594    fn tok_or_in_slice(&mut self, token: &SyntaxToken) -> Result<()> {
595        let content = if token.kind() == SyntaxKind::STRING {
596            value::string(token)
597        } else {
598            value::matches(token)
599        };
600        if self.slice == 0 {
601            let (name, kind_name) = self.regist_tok_name(token)?;
602            self.add_bound(name);
603            self.gen_tok_wrap(&kind_name, |this| {
604                write!(this.out, "{content:?}").unwrap();
605            });
606        } else {
607            write!(self.out, "{content:?}").unwrap();
608        }
609        Ok(())
610    }
611}
612
613pub fn quick_process(src: &str) -> Result<String, String> {
614    let state = &mut rowan_peg_utils::ParseState::default();
615    match parser::decl_list(src, state) {
616        Ok(()) => (),
617        Err(e) => {
618            return Err(format!("parse grammar {e}"));
619        },
620    }
621    let syntax_node = SyntaxNode::new_root(state.finish());
622    let decl_list = DeclList::cast(syntax_node).unwrap();
623    let mut buf = String::new();
624    let mut proc = Processor::from(&mut buf);
625    match proc.start_process(&decl_list) {
626        Ok(()) => {},
627        Err(e) => {
628            let range = match &e {
629                Error::EmptyLiteral(tok)
630                | Error::UnknownLiteral(tok)
631                | Error::MatchesWithoutSlice(tok) => tok.text_range(),
632                Error::DisallowedSlice(node) => node.text_range(),
633            };
634            let index = range.start().into();
635            let (line, col) = line_column::line_column(src, index);
636            return Err(format!("processing error at {line}:{col} {e}"));
637        },
638    }
639    Ok(buf)
640}
641
642#[cfg(test)]
643mod tests {
644    use rowan::TextSize;
645
646    use super::*;
647
648    #[test]
649    fn full_parser() {
650        let s = r#"
651;; use ABNF like grammar
652;; char-val to case-sensitive
653;; prose-val -> regexp
654;; add peg lookaheads `!` `&`
655;; add quiet `~`
656;; add slice `$`
657;; remove num-var
658;;
659;; vim:nowrap
660
661comment     = ~<;[^\n]*(?:\n|$)> @comment
662_           = ~<[ \t\r\n]*> [comment _]
663ident       = ~<(?![0-9])(?:[0-9a-zA-Z\-_]|[^\x00-\xa0])+> @ident
664number      = ~<[0-9]+> @number
665string      = ~(<"> <[^\"\r\n]*> <">) @string
666match       = ~("<" <[^\x3e\r\n]*> ">") @match
667label       = ident / string
668repeat      = "+"
669            / "*" [number]
670            / number ["*" [number]]
671patatom     = ident !(_ "=")            ; a rule reference
672            / string                    ; keyword
673            / match                     ; regular expressions
674            / "[" _ patchoice _ "]"     ; optional
675            / "(" _ patchoice _ ")"     ; simple paren
676            / "{" _ patchoice _ "}"     ; list group brace
677patrepeat   = repeat _ patatom
678            / patatom
679patop       = "&" patrepeat ; positive lookahead
680            / "!" patrepeat ; negative lookahead
681            / "~" patrepeat ; quiet
682            / "$" patrepeat ; slice
683            / patrepeat
684patlist     = patop *(_ patop)
685patchoice   = patlist *(_ "/" _ patlist)
686              *(_ "@" label); extra expected branch
687decl        = ident _ "=" _ patchoice
688decl-list   = +(_ decl) _
689    "#;
690        let mut state = rowan_peg_utils::ParseState::default();
691        parser::decl_list(s, &state).unwrap();
692        dbg!(&state);
693        let node = SyntaxNode::new_root(state.finish());
694        dbg!(&node);
695        assert_eq!(TextSize::of(s), node.text_range().end());
696        dbg!(&s.len());
697        let decl_list = DeclList::cast(node).unwrap();
698        println!("{decl_list}")
699    }
700}