1// pest. The Elegant Parser
2// Copyright (c) 2018 Dragoș Tiselice
3//
4// Licensed under the Apache License, Version 2.0
5// <LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0> or the MIT
6// license <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
7// option. All files in the project carrying such notice may not be copied,
8// modified, or distributed except according to those terms.
9
10//! Different optimizations for pest's ASTs.
11
12use crate::ast::*;
13use std::collections::HashMap;
14
15#[cfg(test)]
16macro_rules! box_tree {
17 ( $node:ident( $( $child:ident( $($args:tt)* ) ),+ ) ) => (
18 $node ( $( Box::new( box_tree!( $child ( $($args )* ) ) ) ),+ )
19 );
20 ($expr:expr) => ($expr);
21}
22
23mod concatenator;
24mod factorizer;
25mod lister;
26mod restorer;
27mod rotater;
28mod skipper;
29mod unroller;
30
31/// Takes pest's ASTs and optimizes them
32pub fn optimize(rules: Vec<Rule>) -> Vec<OptimizedRule> {
33 let map: HashMap = to_hash_map(&rules);
34 let optimized: Vec<OptimizedRule> = rulesimpl Iterator
35 .into_iter()
36 .map(rotater::rotate)
37 .map(|rule: Rule| skipper::skip(rule, &map))
38 .map(unroller::unroll)
39 .map(concatenator::concatenate)
40 .map(factorizer::factor)
41 .map(lister::list)
42 .map(rule_to_optimized_rule)
43 .collect();
44
45 let optimized_map: HashMap = to_optimized_hash_map(&optimized);
46 optimizedimpl Iterator
47 .into_iter()
48 .map(|rule: OptimizedRule| restorer::restore_on_err(rule, &optimized_map))
49 .collect()
50}
51
52fn rule_to_optimized_rule(rule: Rule) -> OptimizedRule {
53 fn to_optimized(expr: Expr) -> OptimizedExpr {
54 match expr {
55 Expr::Str(string) => OptimizedExpr::Str(string),
56 Expr::Insens(string) => OptimizedExpr::Insens(string),
57 Expr::Range(start, end) => OptimizedExpr::Range(start, end),
58 Expr::Ident(ident) => OptimizedExpr::Ident(ident),
59 Expr::PeekSlice(start, end) => OptimizedExpr::PeekSlice(start, end),
60 Expr::PosPred(expr) => OptimizedExpr::PosPred(Box::new(to_optimized(*expr))),
61 Expr::NegPred(expr) => OptimizedExpr::NegPred(Box::new(to_optimized(*expr))),
62 Expr::Seq(lhs, rhs) => {
63 OptimizedExpr::Seq(Box::new(to_optimized(*lhs)), Box::new(to_optimized(*rhs)))
64 }
65 Expr::Choice(lhs, rhs) => {
66 OptimizedExpr::Choice(Box::new(to_optimized(*lhs)), Box::new(to_optimized(*rhs)))
67 }
68 Expr::Opt(expr) => OptimizedExpr::Opt(Box::new(to_optimized(*expr))),
69 Expr::Rep(expr) => OptimizedExpr::Rep(Box::new(to_optimized(*expr))),
70 Expr::Skip(strings) => OptimizedExpr::Skip(strings),
71 Expr::Push(expr) => OptimizedExpr::Push(Box::new(to_optimized(*expr))),
72 #[cfg(feature = "grammar-extras")]
73 Expr::NodeTag(expr, tag) => OptimizedExpr::NodeTag(Box::new(to_optimized(*expr)), tag),
74 #[cfg(feature = "grammar-extras")]
75 Expr::RepOnce(expr) => OptimizedExpr::RepOnce(Box::new(to_optimized(*expr))),
76 #[cfg(not(feature = "grammar-extras"))]
77 Expr::RepOnce(_) => unreachable!("No valid transformation to OptimizedRule"),
78 Expr::RepExact(..) | Expr::RepMin(..) | Expr::RepMax(..) | Expr::RepMinMax(..) => {
79 unreachable!("No valid transformation to OptimizedRule")
80 }
81 }
82 }
83
84 OptimizedRule {
85 name: rule.name,
86 ty: rule.ty,
87 expr: to_optimized(rule.expr),
88 }
89}
90
91macro_rules! to_hash_map {
92 ($func_name:ident, $rule:ty, $expr:ty) => {
93 fn $func_name(rules: &[$rule]) -> HashMap<String, $expr> {
94 rules
95 .iter()
96 .map(|r| (r.name.clone(), r.expr.clone()))
97 .collect()
98 }
99 };
100}
101to_hash_map!(to_hash_map, Rule, Expr);
102to_hash_map!(to_optimized_hash_map, OptimizedRule, OptimizedExpr);
103
104/// The optimized version of the pest AST's `Rule`.
105#[derive(Clone, Debug, Eq, PartialEq)]
106pub struct OptimizedRule {
107 /// The name of the rule.
108 pub name: String,
109 /// The type of the rule.
110 pub ty: RuleType,
111 /// The optimized expression of the rule.
112 pub expr: OptimizedExpr,
113}
114
115/// The optimized version of the pest AST's `Expr`.
116///
117/// # Warning: Semantic Versioning
118/// There may be non-breaking changes to the meta-grammar
119/// between minor versions. Those non-breaking changes, however,
120/// may translate into semver-breaking changes due to the additional variants
121/// propaged from the `Rule` enum. This is a known issue and will be fixed in the
122/// future (e.g. by increasing MSRV and non_exhaustive annotations).
123#[derive(Clone, Debug, Eq, PartialEq)]
124pub enum OptimizedExpr {
125 /// Matches an exact string, e.g. `"a"`
126 Str(String),
127 /// Matches an exact string, case insensitively (ASCII only), e.g. `^"a"`
128 Insens(String),
129 /// Matches one character in the range, e.g. `'a'..'z'`
130 Range(String, String),
131 /// Matches the rule with the given name, e.g. `a`
132 Ident(String),
133 /// Matches a custom part of the stack, e.g. `PEEK[..]`
134 PeekSlice(i32, Option<i32>),
135 /// Positive lookahead; matches expression without making progress, e.g. `&e`
136 PosPred(Box<OptimizedExpr>),
137 /// Negative lookahead; matches if expression doesn't match, without making progress, e.g. `!e`
138 NegPred(Box<OptimizedExpr>),
139 /// Matches a sequence of two expressions, e.g. `e1 ~ e2`
140 Seq(Box<OptimizedExpr>, Box<OptimizedExpr>),
141 /// Matches either of two expressions, e.g. `e1 | e2`
142 Choice(Box<OptimizedExpr>, Box<OptimizedExpr>),
143 /// Optionally matches an expression, e.g. `e?`
144 Opt(Box<OptimizedExpr>),
145 /// Matches an expression zero or more times, e.g. `e*`
146 Rep(Box<OptimizedExpr>),
147 /// Matches an expression one or more times, e.g. `e+`
148 #[cfg(feature = "grammar-extras")]
149 RepOnce(Box<OptimizedExpr>),
150 /// Continues to match expressions until one of the strings in the `Vec` is found
151 Skip(Vec<String>),
152 /// Matches an expression and pushes it to the stack, e.g. `push(e)`
153 Push(Box<OptimizedExpr>),
154 /// Matches an expression and assigns a label to it, e.g. #label = exp
155 #[cfg(feature = "grammar-extras")]
156 NodeTag(Box<OptimizedExpr>, String),
157 /// Restores an expression's checkpoint
158 RestoreOnErr(Box<OptimizedExpr>),
159}
160
161impl OptimizedExpr {
162 /// Returns a top-down iterator over the `OptimizedExpr`.
163 pub fn iter_top_down(&self) -> OptimizedExprTopDownIterator {
164 OptimizedExprTopDownIterator::new(self)
165 }
166
167 /// Applies `f` to the `OptimizedExpr` top-down.
168 pub fn map_top_down<F>(self, mut f: F) -> OptimizedExpr
169 where
170 F: FnMut(OptimizedExpr) -> OptimizedExpr,
171 {
172 fn map_internal<F>(expr: OptimizedExpr, f: &mut F) -> OptimizedExpr
173 where
174 F: FnMut(OptimizedExpr) -> OptimizedExpr,
175 {
176 let expr = f(expr);
177
178 match expr {
179 OptimizedExpr::PosPred(expr) => {
180 let mapped = Box::new(map_internal(*expr, f));
181 OptimizedExpr::PosPred(mapped)
182 }
183 OptimizedExpr::NegPred(expr) => {
184 let mapped = Box::new(map_internal(*expr, f));
185 OptimizedExpr::NegPred(mapped)
186 }
187 OptimizedExpr::Seq(lhs, rhs) => {
188 let mapped_lhs = Box::new(map_internal(*lhs, f));
189 let mapped_rhs = Box::new(map_internal(*rhs, f));
190 OptimizedExpr::Seq(mapped_lhs, mapped_rhs)
191 }
192 OptimizedExpr::Choice(lhs, rhs) => {
193 let mapped_lhs = Box::new(map_internal(*lhs, f));
194 let mapped_rhs = Box::new(map_internal(*rhs, f));
195 OptimizedExpr::Choice(mapped_lhs, mapped_rhs)
196 }
197 OptimizedExpr::Rep(expr) => {
198 let mapped = Box::new(map_internal(*expr, f));
199 OptimizedExpr::Rep(mapped)
200 }
201 OptimizedExpr::Opt(expr) => {
202 let mapped = Box::new(map_internal(*expr, f));
203 OptimizedExpr::Opt(mapped)
204 }
205 OptimizedExpr::Push(expr) => {
206 let mapped = Box::new(map_internal(*expr, f));
207 OptimizedExpr::Push(mapped)
208 }
209 expr => expr,
210 }
211 }
212
213 map_internal(self, &mut f)
214 }
215
216 /// Applies `f` to the `OptimizedExpr` bottom-up.
217 pub fn map_bottom_up<F>(self, mut f: F) -> OptimizedExpr
218 where
219 F: FnMut(OptimizedExpr) -> OptimizedExpr,
220 {
221 fn map_internal<F>(expr: OptimizedExpr, f: &mut F) -> OptimizedExpr
222 where
223 F: FnMut(OptimizedExpr) -> OptimizedExpr,
224 {
225 let mapped = match expr {
226 OptimizedExpr::PosPred(expr) => {
227 let mapped = Box::new(map_internal(*expr, f));
228 OptimizedExpr::PosPred(mapped)
229 }
230 OptimizedExpr::NegPred(expr) => {
231 let mapped = Box::new(map_internal(*expr, f));
232 OptimizedExpr::NegPred(mapped)
233 }
234 OptimizedExpr::Seq(lhs, rhs) => {
235 let mapped_lhs = Box::new(map_internal(*lhs, f));
236 let mapped_rhs = Box::new(map_internal(*rhs, f));
237 OptimizedExpr::Seq(mapped_lhs, mapped_rhs)
238 }
239 OptimizedExpr::Choice(lhs, rhs) => {
240 let mapped_lhs = Box::new(map_internal(*lhs, f));
241 let mapped_rhs = Box::new(map_internal(*rhs, f));
242 OptimizedExpr::Choice(mapped_lhs, mapped_rhs)
243 }
244 OptimizedExpr::Rep(expr) => {
245 let mapped = Box::new(map_internal(*expr, f));
246 OptimizedExpr::Rep(mapped)
247 }
248 OptimizedExpr::Opt(expr) => {
249 let mapped = Box::new(map_internal(*expr, f));
250 OptimizedExpr::Opt(mapped)
251 }
252 OptimizedExpr::Push(expr) => {
253 let mapped = Box::new(map_internal(*expr, f));
254 OptimizedExpr::Push(mapped)
255 }
256 expr => expr,
257 };
258
259 f(mapped)
260 }
261
262 map_internal(self, &mut f)
263 }
264}
265
266impl core::fmt::Display for OptimizedExpr {
267 fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
268 match self {
269 OptimizedExpr::Str(s) => write!(f, "{:?}", s),
270 OptimizedExpr::Insens(s) => write!(f, "^{:?}", s),
271 OptimizedExpr::Range(start, end) => {
272 let start = start.chars().next().expect("Empty range start.");
273 let end = end.chars().next().expect("Empty range end.");
274 write!(f, "({:?}..{:?})", start, end)
275 }
276 OptimizedExpr::Ident(id) => write!(f, "{}", id),
277 OptimizedExpr::PeekSlice(start, end) => match end {
278 Some(end) => write!(f, "PEEK[{}..{}]", start, end),
279 None => write!(f, "PEEK[{}..]", start),
280 },
281 OptimizedExpr::PosPred(expr) => write!(f, "&{}", expr.as_ref()),
282 OptimizedExpr::NegPred(expr) => write!(f, "!{}", expr.as_ref()),
283 OptimizedExpr::Seq(lhs, rhs) => {
284 let mut nodes = Vec::new();
285 nodes.push(lhs);
286 let mut current = rhs;
287 while let OptimizedExpr::Seq(lhs, rhs) = current.as_ref() {
288 nodes.push(lhs);
289 current = rhs;
290 }
291 nodes.push(current);
292 let sequence = nodes
293 .iter()
294 .map(|node| format!("{}", node))
295 .collect::<Vec<_>>()
296 .join(" ~ ");
297 write!(f, "({})", sequence)
298 }
299 OptimizedExpr::Choice(lhs, rhs) => {
300 let mut nodes = Vec::new();
301 nodes.push(lhs);
302 let mut current = rhs;
303 while let OptimizedExpr::Choice(lhs, rhs) = current.as_ref() {
304 nodes.push(lhs);
305 current = rhs;
306 }
307 nodes.push(current);
308 let sequence = nodes
309 .iter()
310 .map(|node| format!("{}", node))
311 .collect::<Vec<_>>()
312 .join(" | ");
313 write!(f, "({})", sequence)
314 }
315 OptimizedExpr::Opt(expr) => write!(f, "{}?", expr),
316 OptimizedExpr::Rep(expr) => write!(f, "{}*", expr),
317 #[cfg(feature = "grammar-extras")]
318 OptimizedExpr::RepOnce(expr) => write!(f, "{}+", expr),
319 OptimizedExpr::Skip(strings) => {
320 let strings = strings
321 .iter()
322 .map(|s| format!("{:?}", s))
323 .collect::<Vec<_>>()
324 .join(" | ");
325 write!(f, "(!({}) ~ ANY)*", strings)
326 }
327 OptimizedExpr::Push(expr) => write!(f, "PUSH({})", expr),
328 #[cfg(feature = "grammar-extras")]
329 OptimizedExpr::NodeTag(expr, tag) => {
330 write!(f, "(#{} = {})", tag, expr)
331 }
332 OptimizedExpr::RestoreOnErr(expr) => core::fmt::Display::fmt(expr.as_ref(), f),
333 }
334 }
335}
336
337/// A top-down iterator over an `OptimizedExpr`.
338pub struct OptimizedExprTopDownIterator {
339 current: Option<OptimizedExpr>,
340 next: Option<OptimizedExpr>,
341 right_branches: Vec<OptimizedExpr>,
342}
343
344impl OptimizedExprTopDownIterator {
345 /// Creates a new top down iterator from an `OptimizedExpr`.
346 pub fn new(expr: &OptimizedExpr) -> Self {
347 let mut iter = OptimizedExprTopDownIterator {
348 current: None,
349 next: None,
350 right_branches: vec![],
351 };
352 iter.iterate_expr(expr.clone());
353 iter
354 }
355
356 fn iterate_expr(&mut self, expr: OptimizedExpr) {
357 self.current = Some(expr.clone());
358 match expr {
359 OptimizedExpr::Seq(lhs, rhs) => {
360 self.right_branches.push(*rhs);
361 self.next = Some(*lhs);
362 }
363 OptimizedExpr::Choice(lhs, rhs) => {
364 self.right_branches.push(*rhs);
365 self.next = Some(*lhs);
366 }
367 OptimizedExpr::PosPred(expr)
368 | OptimizedExpr::NegPred(expr)
369 | OptimizedExpr::Rep(expr)
370 | OptimizedExpr::Opt(expr)
371 | OptimizedExpr::Push(expr) => {
372 self.next = Some(*expr);
373 }
374 _ => {
375 self.next = None;
376 }
377 }
378 }
379}
380
381impl Iterator for OptimizedExprTopDownIterator {
382 type Item = OptimizedExpr;
383
384 fn next(&mut self) -> Option<Self::Item> {
385 let result: Option = self.current.take();
386
387 if let Some(expr: OptimizedExpr) = self.next.take() {
388 self.iterate_expr(expr);
389 } else if let Some(expr: OptimizedExpr) = self.right_branches.pop() {
390 self.iterate_expr(expr);
391 }
392
393 result
394 }
395}
396
397#[cfg(test)]
398mod tests {
399 use super::*;
400
401 #[test]
402 fn rotate() {
403 let rules = {
404 use crate::ast::Expr::*;
405 vec![Rule {
406 name: "rule".to_owned(),
407 ty: RuleType::Normal,
408 expr: box_tree!(Choice(
409 Choice(
410 Choice(Str(String::from("a")), Str(String::from("b"))),
411 Str(String::from("c"))
412 ),
413 Str(String::from("d"))
414 )),
415 }]
416 };
417 let rotated = {
418 use crate::optimizer::OptimizedExpr::*;
419 vec![OptimizedRule {
420 name: "rule".to_owned(),
421 ty: RuleType::Normal,
422 expr: box_tree!(Choice(
423 Str(String::from("a")),
424 Choice(
425 Str(String::from("b")),
426 Choice(Str(String::from("c")), Str(String::from("d")))
427 )
428 )),
429 }]
430 };
431
432 assert_eq!(optimize(rules), rotated);
433 }
434
435 #[test]
436 fn skip() {
437 let rules = {
438 use crate::ast::Expr::*;
439 vec![Rule {
440 name: "rule".to_owned(),
441 ty: RuleType::Atomic,
442 expr: box_tree!(Rep(Seq(
443 NegPred(Choice(Str(String::from("a")), Str(String::from("b")))),
444 Ident(String::from("ANY"))
445 ))),
446 }]
447 };
448 let skipped = vec![OptimizedRule {
449 name: "rule".to_owned(),
450 ty: RuleType::Atomic,
451 expr: OptimizedExpr::Skip(vec![String::from("a"), String::from("b")]),
452 }];
453
454 assert_eq!(optimize(rules), skipped);
455 }
456
457 #[test]
458 fn concat_strings() {
459 let rules = {
460 use crate::ast::Expr::*;
461 vec![Rule {
462 name: "rule".to_owned(),
463 ty: RuleType::Atomic,
464 expr: box_tree!(Seq(
465 Seq(Str(String::from("a")), Str(String::from("b"))),
466 Seq(Str(String::from("c")), Str(String::from("d")))
467 )),
468 }]
469 };
470 let concatenated = vec![OptimizedRule {
471 name: "rule".to_owned(),
472 ty: RuleType::Atomic,
473 expr: OptimizedExpr::Str(String::from("abcd")),
474 }];
475
476 assert_eq!(optimize(rules), concatenated);
477 }
478
479 #[test]
480 fn unroll_loop_exact() {
481 let rules = vec![Rule {
482 name: "rule".to_owned(),
483 ty: RuleType::Atomic,
484 expr: Expr::RepExact(Box::new(Expr::Ident(String::from("a"))), 3),
485 }];
486 let unrolled = {
487 use crate::optimizer::OptimizedExpr::*;
488 vec![OptimizedRule {
489 name: "rule".to_owned(),
490 ty: RuleType::Atomic,
491 expr: box_tree!(Seq(
492 Ident(String::from("a")),
493 Seq(Ident(String::from("a")), Ident(String::from("a")))
494 )),
495 }]
496 };
497
498 assert_eq!(optimize(rules), unrolled);
499 }
500
501 #[test]
502 fn unroll_loop_max() {
503 let rules = vec![Rule {
504 name: "rule".to_owned(),
505 ty: RuleType::Atomic,
506 expr: Expr::RepMax(Box::new(Expr::Str("a".to_owned())), 3),
507 }];
508 let unrolled = {
509 use crate::optimizer::OptimizedExpr::*;
510 vec![OptimizedRule {
511 name: "rule".to_owned(),
512 ty: RuleType::Atomic,
513 expr: box_tree!(Seq(
514 Opt(Str(String::from("a"))),
515 Seq(Opt(Str(String::from("a"))), Opt(Str(String::from("a"))))
516 )),
517 }]
518 };
519
520 assert_eq!(optimize(rules), unrolled);
521 }
522
523 #[test]
524 fn unroll_loop_min() {
525 let rules = vec![Rule {
526 name: "rule".to_owned(),
527 ty: RuleType::Atomic,
528 expr: Expr::RepMin(Box::new(Expr::Str("a".to_owned())), 2),
529 }];
530 let unrolled = {
531 use crate::optimizer::OptimizedExpr::*;
532 vec![OptimizedRule {
533 name: "rule".to_owned(),
534 ty: RuleType::Atomic,
535 expr: box_tree!(Seq(
536 Str(String::from("a")),
537 Seq(Str(String::from("a")), Rep(Str(String::from("a"))))
538 )),
539 }]
540 };
541
542 assert_eq!(optimize(rules), unrolled);
543 }
544
545 #[test]
546 fn unroll_loop_min_max() {
547 let rules = vec![Rule {
548 name: "rule".to_owned(),
549 ty: RuleType::Atomic,
550 expr: Expr::RepMinMax(Box::new(Expr::Str("a".to_owned())), 2, 3),
551 }];
552 let unrolled = {
553 use crate::optimizer::OptimizedExpr::*;
554 vec![OptimizedRule {
555 name: "rule".to_owned(),
556 ty: RuleType::Atomic,
557 /* TODO possible room for improvement here:
558 * if the sequences were rolled out in the opposite
559 * order, we could further optimize the strings
560 * in cases like this.
561 Str(String::from(("aa")),
562 Opt(Str(String::from("a")))
563 */
564 expr: box_tree!(Seq(
565 Str(String::from("a")),
566 Seq(Str(String::from("a")), Opt(Str(String::from("a"))))
567 )),
568 }]
569 };
570
571 assert_eq!(optimize(rules), unrolled);
572 }
573
574 #[test]
575 fn concat_insensitive_strings() {
576 let rules = {
577 use crate::ast::Expr::*;
578 vec![Rule {
579 name: "rule".to_owned(),
580 ty: RuleType::Atomic,
581 expr: box_tree!(Seq(
582 Seq(Insens(String::from("a")), Insens(String::from("b"))),
583 Seq(Insens(String::from("c")), Insens(String::from("d")))
584 )),
585 }]
586 };
587 let concatenated = vec![OptimizedRule {
588 name: "rule".to_owned(),
589 ty: RuleType::Atomic,
590 expr: OptimizedExpr::Insens(String::from("abcd")),
591 }];
592
593 assert_eq!(optimize(rules), concatenated);
594 }
595
596 #[test]
597 fn long_common_sequence() {
598 let rules = {
599 use crate::ast::Expr::*;
600 vec![Rule {
601 name: "rule".to_owned(),
602 ty: RuleType::Silent,
603 expr: box_tree!(Choice(
604 Seq(
605 Ident(String::from("a")),
606 Seq(Ident(String::from("b")), Ident(String::from("c")))
607 ),
608 Seq(
609 Seq(Ident(String::from("a")), Ident(String::from("b"))),
610 Ident(String::from("d"))
611 )
612 )),
613 }]
614 };
615 let optimized = {
616 use crate::optimizer::OptimizedExpr::*;
617 vec![OptimizedRule {
618 name: "rule".to_owned(),
619 ty: RuleType::Silent,
620 expr: box_tree!(Seq(
621 Ident(String::from("a")),
622 Seq(
623 Ident(String::from("b")),
624 Choice(Ident(String::from("c")), Ident(String::from("d")))
625 )
626 )),
627 }]
628 };
629
630 assert_eq!(optimize(rules), optimized);
631 }
632
633 #[test]
634 fn short_common_sequence() {
635 let rules = {
636 use crate::ast::Expr::*;
637 vec![Rule {
638 name: "rule".to_owned(),
639 ty: RuleType::Atomic,
640 expr: box_tree!(Choice(
641 Seq(Ident(String::from("a")), Ident(String::from("b"))),
642 Ident(String::from("a"))
643 )),
644 }]
645 };
646 let optimized = {
647 use crate::optimizer::OptimizedExpr::*;
648 vec![OptimizedRule {
649 name: "rule".to_owned(),
650 ty: RuleType::Atomic,
651 expr: box_tree!(Seq(Ident(String::from("a")), Opt(Ident(String::from("b"))))),
652 }]
653 };
654
655 assert_eq!(optimize(rules), optimized);
656 }
657
658 #[test]
659 fn impossible_common_sequence() {
660 let rules = {
661 use crate::ast::Expr::*;
662 vec![Rule {
663 name: "rule".to_owned(),
664 ty: RuleType::Silent,
665 expr: box_tree!(Choice(
666 Ident(String::from("a")),
667 Seq(Ident(String::from("a")), Ident(String::from("b")))
668 )),
669 }]
670 };
671 let optimized = {
672 use crate::optimizer::OptimizedExpr::*;
673 vec![OptimizedRule {
674 name: "rule".to_owned(),
675 ty: RuleType::Silent,
676 expr: box_tree!(Ident(String::from("a"))),
677 }]
678 };
679
680 assert_eq!(optimize(rules), optimized);
681 }
682
683 #[test]
684 fn lister() {
685 let rules = {
686 use crate::ast::Expr::*;
687 vec![Rule {
688 name: "rule".to_owned(),
689 ty: RuleType::Silent,
690 expr: box_tree!(Seq(
691 Rep(Seq(Ident(String::from("a")), Ident(String::from("b")))),
692 Ident(String::from("a"))
693 )),
694 }]
695 };
696 let optimized = {
697 use crate::optimizer::OptimizedExpr::*;
698 vec![OptimizedRule {
699 name: "rule".to_owned(),
700 ty: RuleType::Silent,
701 expr: box_tree!(Seq(
702 Ident(String::from("a")),
703 Rep(Seq(Ident(String::from("b")), Ident(String::from("a"))))
704 )),
705 }]
706 };
707
708 assert_eq!(optimize(rules), optimized);
709 }
710
711 mod display {
712 use super::super::*;
713 /// In previous implementation of Display for OptimizedExpr
714 /// in commit 48e0a8bd3d43a17c1c78f099610b745d18ec0c5f (actually committed by me),
715 /// Str("\n") will be displayed as
716 /// "
717 /// "
718 ///
719 /// It will not break the compilation in normal use.
720 ///
721 /// But when I use it in automatically generating documents,
722 /// it will quite confusing and we'll be unable to distinguish \n and \r.
723 ///
724 /// And `cargo expand` will emit codes that can't be compiled,
725 /// for it expand `#[doc("...")]` to `/// ...`,
726 /// and when the document comment breaks the line,
727 /// it will be expanded into wrong codes.
728 #[test]
729 fn control_character() {
730 assert_eq!(OptimizedExpr::Str("\n".to_owned()).to_string(), "\"\\n\"");
731 assert_eq!(
732 OptimizedExpr::Insens("\n".to_owned()).to_string(),
733 "^\"\\n\"",
734 );
735 assert_eq!(
736 OptimizedExpr::Range("\n".to_owned(), "\r".to_owned()).to_string(),
737 "('\\n'..'\\r')",
738 );
739 assert_eq!(
740 OptimizedExpr::Skip(vec![
741 "\n".to_owned(),
742 "\r".to_owned(),
743 "\n\r".to_owned(),
744 "\0".to_owned(),
745 ])
746 .to_string(),
747 r#"(!("\n" | "\r" | "\n\r" | "\0") ~ ANY)*"#,
748 );
749
750 assert_ne!(OptimizedExpr::Str("\n".to_owned()).to_string(), "\"\n\"");
751 }
752
753 #[test]
754 fn str() {
755 assert_eq!(OptimizedExpr::Str("a".to_owned()).to_string(), r#""a""#);
756 }
757
758 #[test]
759 fn insens() {
760 assert_eq!(OptimizedExpr::Insens("a".to_owned()).to_string(), r#"^"a""#);
761 }
762
763 #[test]
764 fn range() {
765 assert_eq!(
766 OptimizedExpr::Range("a".to_owned(), "z".to_owned()).to_string(),
767 r#"('a'..'z')"#,
768 );
769 }
770
771 #[test]
772 fn ident() {
773 assert_eq!(OptimizedExpr::Ident("a".to_owned()).to_string(), r#"a"#);
774 }
775
776 #[test]
777 fn peek_slice() {
778 assert_eq!(OptimizedExpr::PeekSlice(0, None).to_string(), "PEEK[0..]");
779 assert_eq!(
780 OptimizedExpr::PeekSlice(0, Some(-1)).to_string(),
781 "PEEK[0..-1]",
782 );
783 assert_eq!(
784 OptimizedExpr::PeekSlice(2, Some(3)).to_string(),
785 "PEEK[2..3]",
786 );
787 assert_eq!(
788 OptimizedExpr::PeekSlice(2, Some(-1)).to_string(),
789 "PEEK[2..-1]",
790 );
791 assert_eq!(OptimizedExpr::PeekSlice(0, None).to_string(), "PEEK[0..]");
792 }
793
794 #[test]
795 fn pos_pred() {
796 assert_eq!(
797 OptimizedExpr::PosPred(Box::new(OptimizedExpr::NegPred(Box::new(
798 OptimizedExpr::Ident("a".to_owned()),
799 ))))
800 .to_string(),
801 "&!a",
802 );
803 assert_eq!(
804 OptimizedExpr::PosPred(Box::new(OptimizedExpr::Choice(
805 Box::new(OptimizedExpr::Rep(Box::new(OptimizedExpr::Ident(
806 "a".to_owned(),
807 )))),
808 Box::new(OptimizedExpr::Str("a".to_owned())),
809 )))
810 .to_string(),
811 r#"&(a* | "a")"#,
812 );
813 assert_eq!(
814 OptimizedExpr::PosPred(Box::new(OptimizedExpr::RestoreOnErr(Box::new(
815 OptimizedExpr::NegPred(Box::new(OptimizedExpr::Ident("a".to_owned()))),
816 ))))
817 .to_string(),
818 "&!a",
819 );
820 }
821
822 #[test]
823 fn neg_pred() {
824 assert_eq!(
825 OptimizedExpr::NegPred(Box::new(OptimizedExpr::Ident("e".to_owned()))).to_string(),
826 r#"!e"#,
827 );
828 assert_eq!(
829 OptimizedExpr::NegPred(Box::new(OptimizedExpr::Choice(
830 Box::new(OptimizedExpr::Push(Box::new(OptimizedExpr::Ident(
831 "a".to_owned(),
832 )))),
833 Box::new(OptimizedExpr::Str("a".to_owned())),
834 )))
835 .to_string(),
836 r#"!(PUSH(a) | "a")"#,
837 );
838 }
839
840 #[test]
841 fn seq() {
842 assert_eq!(
843 OptimizedExpr::Seq(
844 Box::new(OptimizedExpr::Ident("e1".to_owned())),
845 Box::new(OptimizedExpr::Ident("e2".to_owned())),
846 )
847 .to_string(),
848 r#"(e1 ~ e2)"#,
849 );
850 assert_eq!(
851 Expr::Seq(
852 Box::new(Expr::Ident("e1".to_owned())),
853 Box::new(Expr::Seq(
854 Box::new(Expr::Ident("e2".to_owned())),
855 Box::new(Expr::Ident("e3".to_owned())),
856 )),
857 )
858 .to_string(),
859 "(e1 ~ e2 ~ e3)",
860 );
861 assert_eq!(
862 Expr::Seq(
863 Box::new(Expr::Ident("e1".to_owned())),
864 Box::new(Expr::Seq(
865 Box::new(Expr::Ident("e2".to_owned())),
866 Box::new(Expr::Seq(
867 Box::new(Expr::Ident("e3".to_owned())),
868 Box::new(Expr::Ident("e4".to_owned())),
869 )),
870 )),
871 )
872 .to_string(),
873 "(e1 ~ e2 ~ e3 ~ e4)",
874 );
875 assert_eq!(
876 Expr::Seq(
877 Box::new(Expr::Ident("e1".to_owned())),
878 Box::new(Expr::Choice(
879 Box::new(Expr::Ident("e2".to_owned())),
880 Box::new(Expr::Seq(
881 Box::new(Expr::Ident("e3".to_owned())),
882 Box::new(Expr::Ident("e4".to_owned())),
883 )),
884 )),
885 )
886 .to_string(),
887 "(e1 ~ (e2 | (e3 ~ e4)))",
888 );
889 assert_eq!(
890 Expr::Seq(
891 Box::new(Expr::Ident("e1".to_owned())),
892 Box::new(Expr::Seq(
893 Box::new(Expr::Ident("e2".to_owned())),
894 Box::new(Expr::Choice(
895 Box::new(Expr::Ident("e3".to_owned())),
896 Box::new(Expr::Ident("e4".to_owned())),
897 )),
898 )),
899 )
900 .to_string(),
901 "(e1 ~ e2 ~ (e3 | e4))",
902 );
903 assert_eq!(
904 OptimizedExpr::Seq(
905 Box::new(OptimizedExpr::Rep(Box::new(OptimizedExpr::Str(
906 "a".to_owned(),
907 )))),
908 Box::new(OptimizedExpr::Seq(
909 Box::new(OptimizedExpr::Ident("b".to_owned())),
910 Box::new(OptimizedExpr::Insens("c".to_owned())),
911 )),
912 )
913 .to_string(),
914 r#"("a"* ~ b ~ ^"c")"#,
915 );
916 assert_eq!(
917 OptimizedExpr::Seq(
918 Box::new(OptimizedExpr::PosPred(Box::new(OptimizedExpr::Range(
919 "a".to_owned(),
920 "z".to_owned(),
921 )))),
922 Box::new(OptimizedExpr::NegPred(Box::new(OptimizedExpr::Opt(
923 Box::new(OptimizedExpr::Range("A".to_owned(), "Z".to_owned())),
924 )))),
925 )
926 .to_string(),
927 "(&('a'..'z') ~ !('A'..'Z')?)",
928 );
929 }
930
931 #[test]
932 fn choice() {
933 assert_eq!(
934 OptimizedExpr::Choice(
935 Box::new(OptimizedExpr::Ident("e1".to_owned())),
936 Box::new(OptimizedExpr::Ident("e2".to_owned())),
937 )
938 .to_string(),
939 r#"(e1 | e2)"#,
940 );
941 assert_eq!(
942 Expr::Choice(
943 Box::new(Expr::Ident("e1".to_owned())),
944 Box::new(Expr::Choice(
945 Box::new(Expr::Ident("e2".to_owned())),
946 Box::new(Expr::Ident("e3".to_owned())),
947 )),
948 )
949 .to_string(),
950 "(e1 | e2 | e3)",
951 );
952 assert_eq!(
953 Expr::Choice(
954 Box::new(Expr::Ident("e1".to_owned())),
955 Box::new(Expr::Choice(
956 Box::new(Expr::Ident("e2".to_owned())),
957 Box::new(Expr::Choice(
958 Box::new(Expr::Ident("e3".to_owned())),
959 Box::new(Expr::Ident("e4".to_owned())),
960 )),
961 )),
962 )
963 .to_string(),
964 "(e1 | e2 | e3 | e4)",
965 );
966 assert_eq!(
967 Expr::Choice(
968 Box::new(Expr::Ident("e1".to_owned())),
969 Box::new(Expr::Seq(
970 Box::new(Expr::Ident("e2".to_owned())),
971 Box::new(Expr::Choice(
972 Box::new(Expr::Ident("e3".to_owned())),
973 Box::new(Expr::Ident("e4".to_owned())),
974 )),
975 )),
976 )
977 .to_string(),
978 "(e1 | (e2 ~ (e3 | e4)))",
979 );
980 assert_eq!(
981 OptimizedExpr::Choice(
982 Box::new(OptimizedExpr::Str("a".to_owned())),
983 Box::new(OptimizedExpr::Choice(
984 Box::new(OptimizedExpr::Push(Box::new(OptimizedExpr::Ident(
985 "b".to_owned(),
986 )))),
987 Box::new(OptimizedExpr::Insens("c".to_owned())),
988 )),
989 )
990 .to_string(),
991 r#"("a" | PUSH(b) | ^"c")"#,
992 );
993 }
994
995 #[test]
996 fn opt() {
997 assert_eq!(
998 OptimizedExpr::Opt(Box::new(OptimizedExpr::Ident("e".to_owned()))).to_string(),
999 "e?",
1000 );
1001 }
1002
1003 #[test]
1004 fn rep() {
1005 assert_eq!(
1006 OptimizedExpr::Rep(Box::new(OptimizedExpr::Ident("x".to_owned()))).to_string(),
1007 "x*",
1008 );
1009 assert_eq!(
1010 OptimizedExpr::Rep(Box::new(OptimizedExpr::Range(
1011 "0".to_owned(),
1012 "9".to_owned(),
1013 )))
1014 .to_string(),
1015 "('0'..'9')*",
1016 );
1017 }
1018
1019 #[test]
1020 #[cfg(feature = "grammar-extras")]
1021 fn rep_once() {
1022 assert_eq!(
1023 OptimizedExpr::RepOnce(Box::new(OptimizedExpr::Ident("e".to_owned()))).to_string(),
1024 "e+",
1025 );
1026 assert_eq!(
1027 OptimizedExpr::RepOnce(Box::new(OptimizedExpr::Range(
1028 "0".to_owned(),
1029 "9".to_owned(),
1030 )))
1031 .to_string(),
1032 "('0'..'9')+",
1033 );
1034 }
1035
1036 #[test]
1037 fn skip() {
1038 assert_eq!(
1039 OptimizedExpr::Skip(
1040 ["a", "bc"]
1041 .into_iter()
1042 .map(|s| s.to_owned())
1043 .collect::<Vec<_>>(),
1044 )
1045 .to_string(),
1046 r#"(!("a" | "bc") ~ ANY)*"#,
1047 );
1048 }
1049
1050 #[test]
1051 fn inline_skip() {
1052 use crate::ast::Expr::*;
1053 let rules = vec![
1054 Rule {
1055 name: "inline".to_owned(),
1056 ty: RuleType::Atomic,
1057 expr: Str("a".to_owned()),
1058 },
1059 Rule {
1060 name: "skip".to_owned(),
1061 ty: RuleType::Atomic,
1062 expr: box_tree!(Rep(Seq(
1063 NegPred(Choice(
1064 Ident(String::from("inline")),
1065 Str(String::from("b"))
1066 )),
1067 Ident("ANY".to_owned())
1068 ))),
1069 },
1070 ];
1071 let map = to_hash_map(&rules);
1072 let rule = skipper::skip(rules[1].clone(), &map);
1073 assert!(matches!(rule, Rule { expr: Skip(..), .. }));
1074 let choices = match rule.expr {
1075 Skip(choices) => choices,
1076 _ => unreachable!(),
1077 };
1078 assert_eq!(choices, vec!["a".to_owned(), "b".to_owned()]);
1079 }
1080
1081 #[test]
1082 fn push() {
1083 assert_eq!(
1084 OptimizedExpr::Push(Box::new(OptimizedExpr::Ident("e".to_owned()))).to_string(),
1085 "PUSH(e)",
1086 );
1087 }
1088
1089 #[test]
1090 #[cfg(feature = "grammar-extras")]
1091 fn node_tag() {
1092 assert_eq!(
1093 OptimizedExpr::NodeTag(
1094 Box::new(OptimizedExpr::Ident("expr".to_owned())),
1095 "label".to_owned(),
1096 )
1097 .to_string(),
1098 r#"(#label = expr)"#,
1099 );
1100 assert_eq!(
1101 OptimizedExpr::NodeTag(
1102 Box::new(OptimizedExpr::Ident("x".to_owned())),
1103 "X".to_owned(),
1104 )
1105 .to_string(),
1106 r#"(#X = x)"#,
1107 );
1108 assert_eq!(
1109 OptimizedExpr::NodeTag(
1110 Box::new(OptimizedExpr::Seq(
1111 Box::new(OptimizedExpr::Ident("x".to_owned())),
1112 Box::new(OptimizedExpr::Str("y".to_owned())),
1113 )),
1114 "X".to_owned(),
1115 )
1116 .to_string(),
1117 r#"(#X = (x ~ "y"))"#,
1118 );
1119 }
1120
1121 #[test]
1122 fn restore_on_err() {
1123 assert_eq!(
1124 OptimizedExpr::RestoreOnErr(Box::new(OptimizedExpr::Ident("e".to_owned())))
1125 .to_string(),
1126 "e",
1127 );
1128 }
1129 }
1130}
1131