parser/
expr.rs

1use crate::Stmt;
2use anyhow::{Result, anyhow};
3use dynamic::Dynamic;
4use smol_str::SmolStr;
5
6use super::{Parser, ParserErr, Span, Type, try_parse};
7use num_enum::{FromPrimitive, IntoPrimitive};
8
9#[repr(i32)]
10#[derive(Debug, Clone, PartialEq, IntoPrimitive, FromPrimitive)]
11pub enum UnaryOp {
12    Neg = 0,
13    Not,
14    #[num_enum(default)]
15    Unknow = 255,
16}
17
18#[repr(i32)]
19#[derive(Debug, Clone, PartialEq, IntoPrimitive, FromPrimitive)]
20pub enum BinaryOp {
21    Add = 10,
22    Sub,
23    Mul,
24    Div,
25    Mod,
26    Shr,
27    Shl,
28    BitAnd,
29    BitOr,
30    BitXor,
31    AddAssign,
32    SubAssign,
33    MulAssign,
34    DivAssign,
35    ModAssign,
36    ShrAssign,
37    ShlAssign,
38    BitAndAssign,
39    BitOrAssign,
40    BitXorAssign,
41    Assign,
42    Eq,
43    Ne,
44    Lt,
45    Gt,
46    Le,
47    Ge,
48    And,
49    Or,
50    Idx,
51    RangeOpen,
52    RangeClose,
53    #[num_enum(default)]
54    Unknow = 255,
55}
56
57impl BinaryOp {
58    pub fn is_logic(&self) -> bool {
59        matches!(self, Self::And | Self::Or | Self::Eq | Self::Ne | Self::Lt | Self::Gt | Self::Le | Self::Ge)
60    }
61
62    pub fn is_add(&self) -> bool {
63        matches!(self, Self::Add | Self::AddAssign)
64    }
65
66    pub fn is_assign(&self) -> bool {
67        matches!(
68            self,
69            Self::AddAssign | Self::Assign | Self::DivAssign | Self::ModAssign | Self::MulAssign | Self::SubAssign | Self::BitAndAssign | Self::BitOrAssign | Self::BitXorAssign | Self::ShlAssign | Self::ShrAssign
70        )
71    }
72
73    pub fn weight(&self) -> usize {
74        match self {
75            Self::Idx => 30,
76            Self::Mul | Self::Div | Self::Mod => 20,
77            Self::Add | Self::Sub => 19,
78            Self::Shl | Self::Shr => 18,
79            Self::BitAnd => 17,
80            Self::BitXor => 16,
81            Self::BitOr => 15,
82            Self::Eq | Self::Ne | Self::Lt | Self::Gt | Self::Le | Self::Ge => 10,
83            Self::And | Self::Or => 9,
84            Self::RangeOpen | Self::RangeClose => 5,
85            _ => usize::MIN,
86        }
87    }
88}
89
90#[derive(Debug, Clone)]
91pub struct Expr {
92    pub kind: ExprKind,
93    pub span: Span,
94}
95
96#[derive(Debug, Clone, Default)]
97pub enum ExprKind {
98    #[default]
99    Null,
100    Value(Dynamic),
101    Const(usize),
102    Typed {
103        value: Box<Expr>,
104        ty: Type,
105    },
106    Unary {
107        op: UnaryOp,
108        value: Box<Expr>,
109    },
110    Binary {
111        left: Box<Expr>,
112        op: BinaryOp,
113        right: Box<Expr>,
114    },
115    Ident(SmolStr),
116    Var(u32),
117    Capture(u32),
118    Id(u32, Option<Box<Expr>>),
119    Generic {
120        obj: Box<Expr>,
121        params: Vec<Type>,
122    },
123    Assoc {
124        ty: Type,
125        name: SmolStr,
126    },
127    TypedMethod {
128        obj: Box<Expr>,
129        ty: Type,
130        name: SmolStr,
131    },
132    AssocId {
133        id: u32,
134        params: Vec<Type>,
135    },
136    Tuple(Vec<Expr>),
137    List(Vec<Expr>),
138    Repeat {
139        value: Box<Expr>,
140        len: Type,
141    },
142    Dict(Vec<(SmolStr, Expr)>),
143    Range {
144        start: Box<Expr>,
145        stop: Box<Expr>,
146        inclusive: bool,
147    },
148    Call {
149        obj: Box<Expr>,
150        params: Vec<Expr>,
151    },
152    Stmt(Box<Stmt>),
153    Closure {
154        args: Vec<(SmolStr, Type)>,
155        body: Box<Stmt>,
156    },
157}
158
159#[derive(Debug, thiserror::Error)]
160pub enum ExprErr {
161    #[error("{0} 不是标识符")]
162    NotIdent(SmolStr),
163    #[error("{0} 非原生类型")]
164    NotNative(SmolStr),
165    #[error("期望表达式")]
166    ExpectExpr,
167}
168
169impl Default for Expr {
170    fn default() -> Self {
171        Self::new(ExprKind::Null, Span::default())
172    }
173}
174
175impl From<Dynamic> for Expr {
176    fn from(value: Dynamic) -> Self {
177        Self::new(ExprKind::Value(value), Span::default())
178    }
179}
180
181impl Expr {
182    pub fn new(kind: ExprKind, span: Span) -> Self {
183        Self { kind, span }
184    }
185
186    pub fn with_span(mut self, span: Span) -> Self {
187        self.span = span;
188        self
189    }
190
191    pub fn is_range(&self) -> bool {
192        matches!(self.kind, ExprKind::Range { .. })
193    }
194
195    pub fn is_typed(&self) -> bool {
196        matches!(self.kind, ExprKind::Typed { .. })
197    }
198
199    pub fn get_type(&self) -> Type {
200        match &self.kind {
201            ExprKind::Typed { ty, .. } => ty.clone(),
202            ExprKind::Value(v) => v.get_type(),
203            ExprKind::Unary { value, .. } => value.get_type(),
204            ExprKind::Tuple(list) => Type::Tuple(list.iter().map(|l| l.get_type()).collect()),
205            ExprKind::List(list) => {
206                if list.is_empty() {
207                    return Type::list_any();
208                }
209                let mut elem_ty = Type::Any;
210                for item in list {
211                    let item_ty = item.get_type();
212                    elem_ty = if elem_ty.is_any() { item_ty } else { elem_ty + item_ty };
213                }
214                Type::Array(std::rc::Rc::new(elem_ty), list.len() as u32)
215            }
216            ExprKind::Repeat { value, len } => {
217                if let Type::ConstInt(len) = len {
218                    Type::Array(std::rc::Rc::new(value.get_type()), *len as u32)
219                } else {
220                    Type::ArrayParam(std::rc::Rc::new(value.get_type()), std::rc::Rc::new(len.clone()))
221                }
222            }
223            ExprKind::Range { start, .. } => start.get_type(),
224            ExprKind::Stmt(stmt) => stmt.get_type().unwrap_or(Type::Any),
225            _ => Type::Any,
226        }
227    }
228
229    pub fn id(&self) -> Option<u32> {
230        if let ExprKind::Id(id, _) = &self.kind { Some(*id) } else { None }
231    }
232
233    pub fn var(&self) -> Option<u32> {
234        if let ExprKind::Var(idx) = &self.kind { Some(*idx) } else { None }
235    }
236
237    pub fn ident(&self) -> Result<&str> {
238        if let ExprKind::Ident(ident) = &self.kind { Ok(ident.as_str()) } else { Err(ExprErr::NotIdent(SmolStr::from(format!("{:?}", self))).into()) }
239    }
240
241    pub fn binary_op(&self) -> Option<BinaryOp> {
242        if let ExprKind::Binary { op, .. } = &self.kind { Some(op.clone()) } else { None }
243    }
244
245    pub fn is_idx(&self) -> bool {
246        matches!(&self.kind, ExprKind::Binary { op, .. } if *op == BinaryOp::Idx)
247    }
248
249    pub fn is_value(&self) -> bool {
250        match &self.kind {
251            ExprKind::Value(_) => true,
252            ExprKind::Typed { value, ty } => ty.is_native() && value.is_value(),
253            _ => false,
254        }
255    }
256
257    pub fn is_const(&self) -> bool {
258        matches!(self.kind, ExprKind::Const(_))
259    }
260
261    pub fn value(self) -> Result<Dynamic> {
262        match self.kind {
263            ExprKind::Value(v) => Ok(v),
264            ExprKind::Typed { value, ty } => {
265                if ty.is_native() {
266                    Ok(ty.force(value.value()?)?)
267                } else {
268                    Err(anyhow!("不是 Value"))
269                }
270            }
271            _ => Err(anyhow!("不是 Value")),
272        }
273    }
274
275    pub fn binary(self) -> Option<(Expr, BinaryOp, Expr)> {
276        match self.kind {
277            ExprKind::Binary { left, op, right } => Some((*left, op, *right)),
278            _ => None,
279        }
280    }
281
282    pub fn compact(&self) -> Option<Dynamic> {
283        match &self.kind {
284            ExprKind::Value(v) => Some(v.clone()),
285            ExprKind::Unary { op, value } => {
286                if value.is_value() {
287                    let v = value.clone().value().unwrap();
288                    match op {
289                        UnaryOp::Neg => Some(-v),
290                        UnaryOp::Not => Some(!v),
291                        _ => None,
292                    }
293                } else {
294                    None
295                }
296            }
297            ExprKind::Binary { left, op, right } => {
298                if left.is_value() && right.is_value() {
299                    let left = left.clone().value().unwrap();
300                    let right = right.clone().value().unwrap();
301                    let r = match op {
302                        BinaryOp::Add | BinaryOp::AddAssign => left + right,
303                        BinaryOp::Sub | BinaryOp::SubAssign => left - right,
304                        BinaryOp::Mul | BinaryOp::MulAssign => left * right,
305                        BinaryOp::Div | BinaryOp::DivAssign => left / right,
306                        BinaryOp::Mod | BinaryOp::ModAssign => left % right,
307                        BinaryOp::And => Dynamic::Bool(left.is_true() && right.is_true()),
308                        BinaryOp::Or => Dynamic::Bool(left.is_true() || right.is_true()),
309                        BinaryOp::Eq => Dynamic::Bool(left == right),
310                        BinaryOp::Ne => Dynamic::Bool(left != right),
311                        BinaryOp::Le => Dynamic::Bool(left <= right),
312                        BinaryOp::Lt => Dynamic::Bool(left < right),
313                        BinaryOp::Ge => Dynamic::Bool(left >= right),
314                        BinaryOp::Gt => Dynamic::Bool(left > right),
315                        BinaryOp::Shl | BinaryOp::ShlAssign => left << right,
316                        BinaryOp::Shr | BinaryOp::ShrAssign => left >> right,
317                        BinaryOp::Assign => right,
318                        BinaryOp::BitAnd | BinaryOp::BitAndAssign => left & right,
319                        BinaryOp::BitXor | BinaryOp::BitXorAssign => left ^ right,
320                        BinaryOp::BitOr | BinaryOp::BitOrAssign => left | right,
321                        BinaryOp::Idx => {
322                            if let Some(idx) = right.as_int() {
323                                return left.get_idx(idx as usize);
324                            } else if let Ok(key) = SmolStr::try_from(right) {
325                                return left.get_dynamic(&key);
326                            } else {
327                                return None;
328                            }
329                        }
330                        _ => Dynamic::Null,
331                    };
332                    Some(r)
333                } else {
334                    None
335                }
336            }
337            _ => None,
338        }
339    }
340}
341
342impl Parser {
343    fn is_dict_item_boundary(ch: u8) -> bool {
344        matches!(ch, b',' | b'}')
345    }
346
347    fn is_shorthand_field_name(name: &str) -> bool {
348        name.as_bytes().first().is_some_and(|ch| ch.is_ascii_alphabetic() || *ch == b'_')
349    }
350
351    pub(crate) fn looks_like_dict(&mut self) -> bool {
352        let save_pos = self.pos;
353        let result = (|| -> Result<bool> {
354            self.whitespace()?;
355            if self.take(b'{').is_err() {
356                return Ok(false);
357            }
358            self.whitespace()?;
359            if self.take(b'}').is_ok() {
360                return Ok(true);
361            }
362            if self.ident().is_err() && self.string().is_err() {
363                return Ok(false);
364            }
365            self.whitespace()?;
366            Ok(matches!(self.get(), Ok(b':' | b',' | b'}')))
367        })()
368        .unwrap_or(false);
369        self.pos = save_pos;
370        result
371    }
372
373    pub(crate) fn looks_like_empty_dict(&mut self) -> bool {
374        let save_pos = self.pos;
375        let result = (|| -> Result<bool> {
376            self.whitespace()?;
377            self.take(b'{')?;
378            self.whitespace()?;
379            Ok(self.take(b'}').is_ok())
380        })()
381        .unwrap_or(false);
382        self.pos = save_pos;
383        result
384    }
385
386    fn postfix_expr(&mut self, start: usize, mut expr: Expr) -> Result<Expr> {
387        while !self.is_eof() && [b'.', b'[', b'(', b':'].contains(&self.get()?) {
388            if self.ahead()? == b'.' && self.get()? == b'.' {
389                break;
390            }
391            if self.just("::<").is_ok() {
392                let params = crate::parse_list!(self, Vec::new(), b'>', b',', self.get_type_param()?);
393                self.whitespace()?;
394                if self.just("::").is_ok() {
395                    if params.len() != 1 {
396                        return Err(anyhow!("类型提示只能包含一个类型参数"));
397                    }
398                    let name = self.ident()?;
399                    expr = Expr::new(ExprKind::TypedMethod { obj: Box::new(expr), ty: params[0].clone(), name }, Span::new(start, self.current_pos()));
400                } else {
401                    expr = Expr::new(ExprKind::Generic { obj: Box::new(expr), params }, Span::new(start, self.current_pos()));
402                }
403            } else if self.take(b'.').is_ok() {
404                let key_start = self.current_pos();
405                let key = self.ident()?;
406                let right = Expr::new(ExprKind::Value(Dynamic::String(key)), self.span_from(key_start));
407                let span = expr.span.merge(right.span);
408                expr = Expr::new(ExprKind::Binary { left: Box::new(expr), op: BinaryOp::Idx, right: Box::new(right) }, span);
409            } else if self.take(b'[').is_ok() {
410                let key = self.expr(None, None)?.0;
411                self.until(b']')?;
412                let span = Span::new(start, self.current_pos());
413                expr = Expr::new(ExprKind::Binary { left: Box::new(expr), op: BinaryOp::Idx, right: Box::new(key) }, span);
414            } else if self.take(b'(').is_ok() {
415                let params = crate::parse_list!(self, Vec::new(), b')', b',', self.expr(None, None)?.0);
416                expr = Expr::new(ExprKind::Call { obj: Box::new(expr), params }, Span::new(start, self.current_pos()));
417            } else {
418                break;
419            }
420        }
421        Ok(expr.with_span(Span::new(start, self.current_pos())))
422    }
423
424    fn binary_op(&mut self) -> Option<BinaryOp> {
425        if self.just("<<=").is_ok() {
426            Some(BinaryOp::ShlAssign)
427        } else if self.just(">>=").is_ok() {
428            Some(BinaryOp::ShrAssign)
429        } else if self.just("<<").is_ok() {
430            Some(BinaryOp::Shl)
431        } else if self.just(">>").is_ok() {
432            Some(BinaryOp::Shr)
433        } else if self.just(">=").is_ok() {
434            Some(BinaryOp::Ge)
435        } else if self.just("==").is_ok() {
436            Some(BinaryOp::Eq)
437        } else if self.just("!=").is_ok() {
438            Some(BinaryOp::Ne)
439        } else if self.just("<=").is_ok() {
440            Some(BinaryOp::Le)
441        } else if self.just("&&").is_ok() {
442            Some(BinaryOp::And)
443        } else if self.just("||").is_ok() {
444            Some(BinaryOp::Or)
445        } else if self.just("+=").is_ok() {
446            Some(BinaryOp::AddAssign)
447        } else if self.just("-=").is_ok() {
448            Some(BinaryOp::SubAssign)
449        } else if self.just("*=").is_ok() {
450            Some(BinaryOp::MulAssign)
451        } else if self.just("/=").is_ok() {
452            Some(BinaryOp::DivAssign)
453        } else if self.just("%=").is_ok() {
454            Some(BinaryOp::ModAssign)
455        } else if self.just("&=").is_ok() {
456            Some(BinaryOp::BitAndAssign)
457        } else if self.just("|=").is_ok() {
458            Some(BinaryOp::BitOrAssign)
459        } else if self.just("^=").is_ok() {
460            Some(BinaryOp::BitXorAssign)
461        } else if self.just("..=").is_ok() {
462            Some(BinaryOp::RangeClose)
463        } else if self.just("..").is_ok() {
464            Some(BinaryOp::RangeOpen)
465        } else {
466            match self.get() {
467                Ok(b'+') => {
468                    self.pos += 1;
469                    Some(BinaryOp::Add)
470                }
471                Ok(b'-') => {
472                    self.pos += 1;
473                    Some(BinaryOp::Sub)
474                }
475                Ok(b'*') => {
476                    self.pos += 1;
477                    Some(BinaryOp::Mul)
478                }
479                Ok(b'/') => {
480                    self.pos += 1;
481                    Some(BinaryOp::Div)
482                }
483                Ok(b'%') => {
484                    self.pos += 1;
485                    Some(BinaryOp::Mod)
486                }
487                Ok(b'<') => {
488                    self.pos += 1;
489                    Some(BinaryOp::Lt)
490                }
491                Ok(b'>') => {
492                    self.pos += 1;
493                    Some(BinaryOp::Gt)
494                }
495                Ok(b'=') => {
496                    self.pos += 1;
497                    Some(BinaryOp::Assign)
498                }
499                Ok(b'&') => {
500                    self.pos += 1;
501                    Some(BinaryOp::BitAnd)
502                }
503                Ok(b'|') => {
504                    self.pos += 1;
505                    Some(BinaryOp::BitOr)
506                }
507                Ok(b'^') => {
508                    self.pos += 1;
509                    Some(BinaryOp::BitXor)
510                }
511                _ => None,
512            }
513        }
514    }
515
516    pub fn kv(&mut self) -> Result<(SmolStr, Expr)> {
517        let start = self.current_pos();
518        if let Ok(key) = self.ident() {
519            self.whitespace()?;
520            if self.take(b':').is_ok() {
521                let value = self.expr(None, None)?.0;
522                Ok((SmolStr::from(key), value))
523            } else if Self::is_shorthand_field_name(&key) && self.get().map(Self::is_dict_item_boundary).unwrap_or(false) {
524                let span = Span::new(start, start + key.len());
525                Ok((key.clone(), Expr::new(ExprKind::Ident(key), span)))
526            } else {
527                Err(anyhow!("expect ':' after field name"))
528            }
529        } else if let Ok(key) = self.string() {
530            self.until(b':')?;
531            let value = self.expr(None, None)?.0;
532            Ok((SmolStr::from(key), value))
533        } else {
534            Err(anyhow!("expect string as key"))
535        }
536    }
537
538    pub fn base_expr(&mut self, allow_struct_literal: bool) -> Result<Expr> {
539        self.check_fatal()?;
540        let start = self.current_pos();
541        if let Ok(s) = self.text() {
542            let expr = Expr::new(ExprKind::Value(Dynamic::String(s)), self.span_from(start));
543            self.postfix_expr(start, expr)
544        } else if self.get().map(|c| c.is_ascii_digit()).unwrap_or(false) {
545            // 数字开头一定是数字字面量:解析失败(如越界)直接上抛,
546            // 不要回落到其它产生式而把"超出范围"错误吞成笼统的"期望表达式"。
547            let n = self.number()?;
548            let expr = if let Ok(ty) = self.get_type() {
549                if ty.is_native() {
550                    Expr::new(ExprKind::Typed { value: Box::new(Expr::new(ExprKind::Value(n), self.span_from(start))), ty }, self.span_from(start))
551                } else {
552                    return Err(ExprErr::NotNative(SmolStr::from(format!("{:?}", ty))).into());
553                }
554            } else {
555                Expr::new(ExprKind::Value(n), self.span_from(start))
556            };
557            self.postfix_expr(start, expr)
558        } else if self.keyword("true").is_ok() {
559            let expr = Expr::new(ExprKind::Value(Dynamic::Bool(true)), self.span_from(start));
560            self.postfix_expr(start, expr)
561        } else if self.keyword("false").is_ok() {
562            let expr = Expr::new(ExprKind::Value(Dynamic::Bool(false)), self.span_from(start));
563            self.postfix_expr(start, expr)
564        } else if self.keyword("null").is_ok() {
565            let expr = Expr::new(ExprKind::Value(Dynamic::Null), self.span_from(start));
566            self.postfix_expr(start, expr)
567        } else if let Ok(ident) = self.ident() {
568            self.whitespace()?;
569            let save_pos = self.pos;
570            if self.take(b'<').is_ok() {
571                let typed_literal = (|| -> Result<Expr> {
572                    let type_params = crate::parse_list!(self, Vec::new(), b'>', b',', self.get_type_param()?);
573                    self.whitespace()?;
574                    if self.just("::").is_ok() {
575                        let name = self.ident()?;
576                        let expr = Expr::new(ExprKind::Assoc { ty: Type::Ident { name: ident.clone(), params: type_params }, name }, self.span_from(start));
577                        return self.postfix_expr(start, expr);
578                    }
579                    if allow_struct_literal
580                        && self.looks_like_dict()
581                        && let Ok(b'{') = self.get()
582                        && let Ok(dict) = try_parse!(self, self.dict())
583                    {
584                        return Ok(Expr::new(ExprKind::Typed { value: Box::new(dict), ty: Type::Ident { name: ident.clone(), params: type_params } }, self.span_from(start)));
585                    }
586                    Err(ExprErr::ExpectExpr.into())
587                })();
588                if let Ok(expr) = typed_literal {
589                    return Ok(expr);
590                }
591                self.pos = save_pos;
592            }
593            if allow_struct_literal
594                && self.looks_like_dict()
595                && let Ok(b'{') = self.get()
596                && let Ok(dict) = try_parse!(self, self.dict())
597            {
598                return Ok(Expr::new(ExprKind::Typed { value: Box::new(dict), ty: Type::Ident { name: ident, params: Vec::new() } }, self.span_from(start)));
599            }
600            self.postfix_expr(start, Expr::new(ExprKind::Ident(ident), self.span_from(start)))
601        } else {
602            Err(ExprErr::ExpectExpr.into())
603        }
604    }
605
606    pub(crate) fn dict(&mut self) -> Result<Expr> {
607        let start = self.current_pos();
608        self.pos += 1;
609        Ok(Expr::new(ExprKind::Dict(crate::parse_list!(self, Vec::new(), b'}', b',', self.kv()?)), self.span_from(start)))
610    }
611
612    fn static_dynamic_literal_expr(&mut self) -> Result<Expr> {
613        let start = self.current_pos();
614        let value = self.static_dynamic_value()?;
615        Ok(Expr::new(ExprKind::Value(value), self.span_from(start)))
616    }
617
618    fn static_dynamic_value(&mut self) -> Result<Dynamic> {
619        self.whitespace()?;
620        if self.get()? == b'[' {
621            return self.static_dynamic_list();
622        }
623        if self.get()? == b'{' {
624            return self.static_dynamic_map();
625        }
626        if self.take(b'-').is_ok() {
627            return Ok(-self.number()?);
628        }
629        if let Ok(text) = self.text() {
630            return Ok(Dynamic::String(text));
631        }
632        if let Ok(number) = self.number() {
633            return Ok(number);
634        }
635        if self.keyword("true").is_ok() {
636            return Ok(Dynamic::Bool(true));
637        }
638        if self.keyword("false").is_ok() {
639            return Ok(Dynamic::Bool(false));
640        }
641        if self.keyword("null").is_ok() {
642            return Ok(Dynamic::Null);
643        }
644        Err(ExprErr::ExpectExpr.into())
645    }
646
647    fn static_dynamic_list(&mut self) -> Result<Dynamic> {
648        self.take(b'[')?;
649        let mut values = Vec::new();
650        loop {
651            self.whitespace()?;
652            if self.take(b']').is_ok() {
653                break;
654            }
655            values.push(self.static_dynamic_value()?);
656            self.whitespace()?;
657            if self.take(b',').is_ok() {
658                continue;
659            }
660            self.until(b']')?;
661            break;
662        }
663        Ok(Dynamic::list(values))
664    }
665
666    fn static_dynamic_map(&mut self) -> Result<Dynamic> {
667        self.take(b'{')?;
668        let mut values = std::collections::BTreeMap::new();
669        loop {
670            self.whitespace()?;
671            if self.take(b'}').is_ok() {
672                break;
673            }
674            let key = if let Ok(key) = self.ident() { key } else { self.string()? };
675            self.until(b':')?;
676            let value = self.static_dynamic_value()?;
677            values.insert(key, value);
678            self.whitespace()?;
679            if self.take(b',').is_ok() {
680                continue;
681            }
682            self.until(b'}')?;
683            break;
684        }
685        Ok(Dynamic::map(values))
686    }
687
688    pub fn get_expr(&mut self) -> Result<Expr> {
689        self.expr(None, None).map(|(e, _)| e)
690    }
691
692    pub fn get_expr_without_struct_literal(&mut self) -> Result<Expr> {
693        self.expr_with_min_weight(None, None, 0, false).map(|(e, _)| e)
694    }
695
696    pub fn expr(&mut self, left: Option<(Expr, bool)>, left_op: Option<BinaryOp>) -> Result<(Expr, bool)> {
697        self.expr_with_min_weight(left, left_op, 0, true)
698    }
699
700    fn expr_with_min_weight(&mut self, left: Option<(Expr, bool)>, left_op: Option<BinaryOp>, min_weight: usize, allow_struct_literal: bool) -> Result<(Expr, bool)> {
701        self.check_fatal()?;
702        self.enter_depth()?;
703        let result = self.expr_with_min_weight_inner(left, left_op, min_weight, allow_struct_literal);
704        self.exit_depth();
705        result
706    }
707
708    fn expr_with_min_weight_inner(&mut self, left: Option<(Expr, bool)>, left_op: Option<BinaryOp>, min_weight: usize, allow_struct_literal: bool) -> Result<(Expr, bool)> {
709        self.whitespace()?;
710        if self.is_eof() {
711            return left.ok_or(ParserErr::EndofInput.into());
712        }
713        let start = self.current_pos();
714        let ch = self.get()?;
715        let mut expr = if ch == b'(' {
716            let start = self.current_pos();
717            self.pos += 1;
718            self.whitespace()?;
719            if self.take(b')').is_ok() {
720                let expr = Expr::new(ExprKind::Tuple(Vec::new()), Span::new(start, self.current_pos()));
721                return Ok((self.postfix_expr(start, expr)?, true));
722            }
723            let (e, _closed) = self.expr_with_min_weight(None, None, 0, true)?;
724            self.whitespace()?;
725            if self.get()? == b',' {
726                self.pos += 1;
727                let list = crate::parse_list!(self, vec![e], b')', b',', self.expr_with_min_weight(None, None, 0, true)?.0);
728                let expr = Expr::new(ExprKind::Tuple(list), Span::new(start, self.current_pos()));
729                Ok((self.postfix_expr(start, expr)?, true))
730            } else {
731                self.until(b')')?;
732                let expr = e.with_span(Span::new(start, self.current_pos()));
733                Ok((self.postfix_expr(start, expr)?, true))
734            }
735        } else if ch == b'!' && self.ahead().map(|a| a != b'=').unwrap_or(true) {
736            let start = self.current_pos();
737            self.pos += 1;
738            let value = self.expr_with_min_weight(None, None, BinaryOp::Mul.weight() + 1, allow_struct_literal)?.0;
739            Ok((Expr::new(ExprKind::Unary { op: UnaryOp::Not, value: Box::new(value) }, Span::new(start, self.current_pos())), false))
740        } else if ch == b'-' && self.ahead().map(|a| a != b'=').unwrap_or(true) && (left.is_none() || (left.is_some() && left_op.is_some())) {
741            let start = self.current_pos();
742            self.pos += 1;
743            let value = self.expr_with_min_weight(None, None, BinaryOp::Mul.weight() + 1, allow_struct_literal)?.0;
744            Ok((Expr::new(ExprKind::Unary { op: UnaryOp::Neg, value: Box::new(value) }, Span::new(start, self.current_pos())), false))
745        } else if ch == b'[' {
746            if let Ok(expr) = try_parse!(self, self.static_dynamic_literal_expr()) {
747                Ok((self.postfix_expr(start, expr)?, false))
748            } else {
749                let start = self.current_pos();
750                self.pos += 1;
751                self.whitespace()?;
752                if self.take(b']').is_ok() {
753                    let expr = Expr::new(ExprKind::List(Vec::new()), Span::new(start, self.current_pos()));
754                    Ok((self.postfix_expr(start, expr)?, false))
755                } else {
756                    let first = self.expr_with_min_weight(None, None, 0, true)?.0;
757                    self.whitespace()?;
758                    if self.take(b';').is_ok() {
759                        let len = self.get_type_param()?;
760                        self.until(b']')?;
761                        let expr = Expr::new(ExprKind::Repeat { value: Box::new(first), len }, Span::new(start, self.current_pos()));
762                        Ok((self.postfix_expr(start, expr)?, false))
763                    } else {
764                        let mut items = vec![first];
765                        let mut closed = false;
766                        while self.take(b',').is_ok() {
767                            self.whitespace()?;
768                            if self.take(b']').is_ok() {
769                                closed = true;
770                                break;
771                            }
772                            items.push(self.expr_with_min_weight(None, None, 0, true)?.0);
773                            self.whitespace()?;
774                        }
775                        if !closed {
776                            self.until(b']')?;
777                        }
778                        let expr = Expr::new(ExprKind::List(items), Span::new(start, self.current_pos()));
779                        Ok((self.postfix_expr(start, expr)?, false))
780                    }
781                }
782            }
783        } else if ch == b'{'
784            && (left.is_none() || left_op.is_some())
785            && let Ok(expr) = try_parse!(self, self.static_dynamic_literal_expr())
786        {
787            Ok((self.postfix_expr(start, expr)?, false))
788        } else if ch == b'{'
789            && (left.is_none() || left_op.is_some())
790            && let Ok(dict) = try_parse!(self, self.dict())
791        {
792            Ok((self.postfix_expr(start, dict)?, false))
793        } else if (left.is_none() || left_op.is_some()) && self.keyword("if").is_ok() {
794            let stmt = self.if_block()?;
795            Ok((Expr::new(ExprKind::Stmt(Box::new(stmt)), Span::new(start, self.current_pos())), true))
796        } else if ch == b'|' && left.is_none() {
797            let start = self.current_pos();
798            self.pos += 1;
799            let args = crate::parse_list!(self, Vec::new(), b'|', b',', self.ident_typed()?);
800            let body = Box::new(self.function_body(&args)?);
801            let expr = Expr::new(ExprKind::Closure { args, body }, Span::new(start, self.current_pos()));
802            Ok((self.postfix_expr(start, expr)?, true))
803        } else if let Some(this_op) = self.binary_op() {
804            let (left, close) = left.ok_or(anyhow!("{:?} need left value", this_op))?;
805            if this_op == BinaryOp::RangeOpen {
806                self.whitespace()?;
807                if self.get()? == b']' {
808                    let span = Span::new(left.span.start, self.current_pos());
809                    let stop = Expr::new(ExprKind::Value(Dynamic::Null), Span::empty(self.current_pos()));
810                    return Ok((Expr::new(ExprKind::Range { start: Box::new(left), stop: Box::new(stop), inclusive: false }, span), false));
811                }
812            }
813            if this_op.weight() < min_weight {
814                self.pos = start;
815                return Ok((left, close));
816            }
817            // range 的上界要按完整子表达式解析(优先级降到 range 之上),
818            // 否则 `0 .. n * 2` 只会把 `n` 当上界,`* 2` 反而套在整个 range 外面。
819            if matches!(this_op, BinaryOp::RangeOpen | BinaryOp::RangeClose) {
820                let stop = self.expr_with_min_weight(None, None, this_op.weight() + 1, allow_struct_literal)?.0;
821                let span = left.span.merge(stop.span);
822                let inclusive = this_op == BinaryOp::RangeClose;
823                let range = Expr::new(ExprKind::Range { start: Box::new(left), stop: Box::new(stop), inclusive }, span);
824                return self.expr_with_min_weight(Some((range, false)), None, min_weight, allow_struct_literal);
825            }
826            if left_op.is_some() {
827                return Err(anyhow!("unexpected binary op {:?}", this_op));
828            }
829            return if !close && left.binary_op().map(|op| op.weight() < this_op.weight()).unwrap_or(false) {
830                let (binary_left, op, right) = left.binary().unwrap();
831                let this_weight = this_op.weight();
832                let new_right = self.expr_with_min_weight(Some((right, false)), Some(this_op), this_weight, allow_struct_literal)?.0;
833                let span = binary_left.span.merge(new_right.span);
834                let expr = Expr::new(ExprKind::Binary { left: Box::new(binary_left), op, right: Box::new(new_right) }, span);
835                self.expr_with_min_weight(Some((expr, false)), None, min_weight, allow_struct_literal)
836            } else {
837                self.expr_with_min_weight(Some((left, false)), Some(this_op), min_weight, allow_struct_literal)
838            };
839        } else if self.keyword("as").is_ok() && left.is_some() {
840            let value = left.unwrap().0;
841            let start = value.span.start;
842            let ty = self.get_type()?;
843            return Ok((Expr::new(ExprKind::Typed { value: Box::new(value), ty }, Span::new(start, self.current_pos())), false));
844        } else {
845            self.base_expr(allow_struct_literal).map(|e| (e, false))
846        };
847
848        if left.is_some() {
849            if let Some(op) = left_op {
850                let left = left.unwrap().0;
851                let right = expr?.0;
852                let span = left.span.merge(right.span);
853                expr = Ok((
854                    match op {
855                        BinaryOp::RangeOpen => Expr::new(ExprKind::Range { start: Box::new(left), stop: Box::new(right), inclusive: false }, span),
856                        BinaryOp::RangeClose => Expr::new(ExprKind::Range { start: Box::new(left), stop: Box::new(right), inclusive: true }, span),
857                        _ => Expr::new(ExprKind::Binary { left: Box::new(left), op, right: Box::new(right) }, span),
858                    },
859                    false,
860                ));
861            } else if expr.is_ok() {
862                return Err(anyhow!("unexpected {:?}", expr));
863            } else {
864                return Ok((left.unwrap().0, false));
865            }
866        }
867        let result = self.expr_with_min_weight(Some(expr?), None, min_weight, allow_struct_literal)?;
868        Ok(result)
869    }
870}
parser/expr.rs

parser/
expr.rs
