cl-parser: Outline precedence parser
This commit is contained in:
parent
533436afc1
commit
de63a8c123
@ -7,6 +7,9 @@ use crate::error::{
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use cl_ast::*;
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use cl_lexer::Lexer;
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// Precedence climbing expression parser
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mod prec;
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/// Parses a sequence of [Tokens](Token) into an [AST](cl_ast)
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#[derive(Debug)]
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pub struct Parser<'t> {
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@ -891,400 +894,12 @@ impl Parse<'_> for Expr {
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impl Parse<'_> for ExprKind {
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/// Parses an [ExprKind] at the lowest precedence level
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// Implementer's note: Do not call this from within [Parser::exprkind]
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// Implementer's note: Do not call this from within [prec::exprkind]
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fn parse(p: &mut Parser<'_>) -> PResult<ExprKind> {
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prec::exprkind(p, 0)
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}
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}
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mod prec {
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//! Parses an [ExprKind] using a modified pratt parser
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//!
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//! See also: [Expr::parse], [ExprKind::parse]
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//!
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//! Implementer's note: [ExprKind::parse] is the public API for parsing [ExprKind]s.
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//! Do not call it from within this function.
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use super::{Parse, *};
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/// Parses an [ExprKind]
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pub fn exprkind(p: &mut Parser, power: u8) -> PResult<ExprKind> {
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let parsing = Parsing::ExprKind;
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// Prefix expressions
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let mut head = match p.peek_kind(Parsing::Unary)? {
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literal_like!() => Literal::parse(p)?.into(),
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path_like!() => exprkind_pathlike(p)?,
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TokenKind::Amp | TokenKind::AmpAmp => AddrOf::parse(p)?.into(),
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TokenKind::LCurly => Block::parse(p)?.into(),
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TokenKind::LBrack => exprkind_arraylike(p)?,
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TokenKind::LParen => exprkind_tuplelike(p)?,
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TokenKind::Let => Let::parse(p)?.into(),
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TokenKind::While => ExprKind::While(While::parse(p)?),
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TokenKind::If => ExprKind::If(If::parse(p)?),
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TokenKind::For => ExprKind::For(For::parse(p)?),
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TokenKind::Break => ExprKind::Break(Break::parse(p)?),
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TokenKind::Return => ExprKind::Return(Return::parse(p)?),
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TokenKind::Continue => {
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p.consume_peeked();
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ExprKind::Continue
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}
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op => {
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let (kind, prec) =
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from_prefix(op).ok_or_else(|| p.error(Unexpected(op), parsing))?;
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let ((), after) = prec.prefix().expect("should have a precedence");
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p.consume_peeked();
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Unary { kind, tail: exprkind(p, after)?.into() }.into()
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}
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};
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fn from_postfix(op: TokenKind) -> Option<Precedence> {
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Some(match op {
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TokenKind::LBrack => Precedence::Index,
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TokenKind::LParen => Precedence::Call,
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TokenKind::Dot => Precedence::Member,
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_ => None?,
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})
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}
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while let Ok(op) = p.peek_kind(parsing) {
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// Postfix expressions
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if let Some((before, ())) = from_postfix(op).and_then(Precedence::postfix) {
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if before < power {
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break;
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}
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p.consume_peeked();
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head = match op {
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TokenKind::LBrack => {
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let indices =
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sep(Expr::parse, TokenKind::Comma, TokenKind::RBrack, parsing)(p)?;
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p.match_type(TokenKind::RBrack, parsing)?;
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ExprKind::Index(Index { head: head.into(), indices })
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}
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TokenKind::LParen => {
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let exprs =
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sep(Expr::parse, TokenKind::Comma, TokenKind::RParen, parsing)(p)?;
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p.match_type(TokenKind::RParen, parsing)?;
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Binary {
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kind: BinaryKind::Call,
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parts: (head, Tuple { exprs }.into()).into(),
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}
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.into()
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}
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TokenKind::Dot => {
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let kind = MemberKind::parse(p)?;
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Member { head: Box::new(head), kind }.into()
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}
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_ => Err(p.error(Unexpected(op), parsing))?,
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};
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continue;
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}
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// infix expressions
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if let Some((kind, prec)) = from_infix(op) {
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let (before, after) = prec.infix().expect("should have a precedence");
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if before < power {
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break;
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}
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p.consume_peeked();
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let tail = exprkind(p, after)?;
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head = Binary { kind, parts: (head, tail).into() }.into();
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continue;
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}
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if let Some((kind, prec)) = from_modify(op) {
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let (before, after) = prec.infix().expect("should have a precedence");
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if before < power {
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break;
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}
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p.consume_peeked();
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let tail = exprkind(p, after)?;
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head = Modify { kind, parts: (head, tail).into() }.into();
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continue;
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}
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if let TokenKind::Eq = op {
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let (before, after) = Precedence::Assign
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.infix()
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.expect("should have a precedence");
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if before < power {
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break;
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}
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p.consume_peeked();
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let tail = exprkind(p, after)?;
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head = Assign { parts: (head, tail).into() }.into();
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continue;
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}
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if let TokenKind::As = op {
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let before = Precedence::Cast.level();
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if before < power {
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break;
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}
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p.consume_peeked();
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let ty = Ty::parse(p)?;
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head = Cast { head: head.into(), ty }.into();
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continue;
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}
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break;
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}
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Ok(head)
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}
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/// [Array] = '[' ([Expr] ',')* [Expr]? ']'
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///
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/// Array and ArrayRef are ambiguous until the second token,
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/// so they can't be independent subexpressions
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fn exprkind_arraylike(p: &mut Parser) -> PResult<ExprKind> {
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const P: Parsing = Parsing::Array;
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const START: TokenKind = TokenKind::LBrack;
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const END: TokenKind = TokenKind::RBrack;
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p.match_type(START, P)?;
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let out = match p.peek_kind(P)? {
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END => Array { values: vec![] }.into(),
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_ => exprkind_array_rep(p)?,
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};
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p.match_type(END, P)?;
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Ok(out)
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}
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/// [ArrayRep] = `[` [Expr] `;` [Expr] `]`
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fn exprkind_array_rep(p: &mut Parser) -> PResult<ExprKind> {
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const P: Parsing = Parsing::Array;
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const END: TokenKind = TokenKind::RBrack;
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let first = Expr::parse(p)?;
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Ok(match p.peek_kind(P)? {
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TokenKind::Semi => ArrayRep {
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value: first.kind.into(),
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repeat: {
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p.consume_peeked();
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Box::new(exprkind(p, 0)?)
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},
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}
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.into(),
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TokenKind::RBrack => Array { values: vec![first] }.into(),
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TokenKind::Comma => Array {
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values: {
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p.consume_peeked();
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let mut out = vec![first];
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out.extend(sep(Expr::parse, TokenKind::Comma, END, P)(p)?);
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out
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},
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}
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.into(),
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ty => Err(p.error(Unexpected(ty), P))?,
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})
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}
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/// [Group] = `(`([Empty](ExprKind::Empty)|[Expr]|[Tuple])`)`
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///
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/// [ExprKind::Empty] and [Group] are special cases of [Tuple]
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fn exprkind_tuplelike(p: &mut Parser) -> PResult<ExprKind> {
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p.match_type(TokenKind::LParen, Parsing::Group)?;
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let out = match p.peek_kind(Parsing::Group)? {
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TokenKind::RParen => Ok(ExprKind::Empty),
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_ => exprkind_group(p),
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};
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p.match_type(TokenKind::RParen, Parsing::Group)?;
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out
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}
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/// [Group] = `(`([Empty](ExprKind::Empty)|[Expr]|[Tuple])`)`
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fn exprkind_group(p: &mut Parser) -> PResult<ExprKind> {
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let first = Expr::parse(p)?;
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match p.peek_kind(Parsing::Group)? {
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TokenKind::Comma => {
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let mut exprs = vec![first];
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p.consume_peeked();
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while TokenKind::RParen != p.peek_kind(Parsing::Tuple)? {
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exprs.push(Expr::parse(p)?);
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match p.peek_kind(Parsing::Tuple)? {
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TokenKind::Comma => p.consume_peeked(),
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_ => break,
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};
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}
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Ok(Tuple { exprs }.into())
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}
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_ => Ok(Group { expr: first.kind.into() }.into()),
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}
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}
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/// Parses an expression beginning with a [Path] (i.e. [Path] or [Structor])
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fn exprkind_pathlike(p: &mut Parser) -> PResult<ExprKind> {
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let head = Path::parse(p)?;
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Ok(match p.match_type(TokenKind::Colon, Parsing::Path) {
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Ok(_) => ExprKind::Structor(structor_body(p, head)?),
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Err(_) => ExprKind::Path(head),
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})
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}
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/// [Structor]Body = `{` ([Fielder] `,`)* [Fielder]? `}`
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fn structor_body(p: &mut Parser, to: Path) -> PResult<Structor> {
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let init = delim(
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sep(
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Fielder::parse,
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TokenKind::Comma,
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CURLIES.1,
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Parsing::Structor,
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),
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CURLIES,
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Parsing::Structor,
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)(p)?;
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Ok(Structor { to, init })
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}
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/// Precedence provides a total ordering among operators
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#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
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pub enum Precedence {
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Assign,
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Compare,
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Range,
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Logic,
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Bitwise,
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Shift,
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Factor,
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Term,
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Unary,
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Index,
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Cast,
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Member, // left-associative
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Call,
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}
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impl Precedence {
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#[inline]
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pub const fn level(self) -> u8 {
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(self as u8) << 1
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}
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pub fn prefix(self) -> Option<((), u8)> {
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match self {
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Self::Assign => Some(((), self.level())),
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Self::Unary => Some(((), self.level())),
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_ => None,
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}
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}
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pub fn infix(self) -> Option<(u8, u8)> {
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let level = self.level();
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match self {
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Self::Unary => None,
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Self::Assign => Some((level + 1, level)),
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_ => Some((level, level + 1)),
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}
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}
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pub fn postfix(self) -> Option<(u8, ())> {
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match self {
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Self::Index | Self::Call | Self::Member => Some((self.level(), ())),
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_ => None,
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}
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}
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}
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impl From<ModifyKind> for Precedence {
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fn from(_value: ModifyKind) -> Self {
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Precedence::Assign
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}
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}
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impl From<BinaryKind> for Precedence {
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fn from(value: BinaryKind) -> Self {
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use BinaryKind as Op;
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match value {
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Op::Call => Precedence::Call,
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Op::Mul | Op::Div | Op::Rem => Precedence::Term,
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Op::Add | Op::Sub => Precedence::Factor,
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Op::Shl | Op::Shr => Precedence::Shift,
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Op::BitAnd | Op::BitOr | Op::BitXor => Precedence::Bitwise,
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Op::LogAnd | Op::LogOr | Op::LogXor => Precedence::Logic,
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Op::RangeExc | Op::RangeInc => Precedence::Range,
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Op::Lt | Op::LtEq | Op::Equal | Op::NotEq | Op::GtEq | Op::Gt => {
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Precedence::Compare
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}
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}
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}
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}
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impl From<UnaryKind> for Precedence {
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fn from(value: UnaryKind) -> Self {
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use UnaryKind as Op;
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match value {
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Op::Loop => Precedence::Assign,
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Op::Deref | Op::Neg | Op::Not | Op::At | Op::Tilde => Precedence::Unary,
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}
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}
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}
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/// Creates helper functions for turning TokenKinds into AST operators
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macro operator($($name:ident ($takes:ident => $returns:ident) {$($t:ident => $p:ident),*$(,)?};)*) {$(
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pub fn $name (value: $takes) -> Option<($returns, Precedence)> {
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match value {
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$($takes::$t => Some(($returns::$p, Precedence::from($returns::$p))),)*
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_ => None?,
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}
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})*
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}
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operator! {
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from_prefix (TokenKind => UnaryKind) {
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Loop => Loop,
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Star => Deref,
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Minus => Neg,
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Bang => Not,
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At => At,
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Tilde => Tilde,
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};
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from_modify(TokenKind => ModifyKind) {
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AmpEq => And,
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BarEq => Or,
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XorEq => Xor,
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LtLtEq => Shl,
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GtGtEq => Shr,
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PlusEq => Add,
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MinusEq => Sub,
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StarEq => Mul,
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SlashEq => Div,
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RemEq => Rem,
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};
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from_infix (TokenKind => BinaryKind) {
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Lt => Lt,
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LtEq => LtEq,
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EqEq => Equal,
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BangEq => NotEq,
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GtEq => GtEq,
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Gt => Gt,
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DotDot => RangeExc,
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DotDotEq => RangeInc,
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AmpAmp => LogAnd,
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BarBar => LogOr,
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XorXor => LogXor,
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Amp => BitAnd,
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Bar => BitOr,
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Xor => BitXor,
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LtLt => Shl,
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GtGt => Shr,
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Plus => Add,
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Minus => Sub,
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Star => Mul,
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Slash => Div,
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Rem => Rem,
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};
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}
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}
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impl Parse<'_> for Let {
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fn parse(p: &mut Parser) -> PResult<Let> {
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p.consume_peeked();
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385
compiler/cl-parser/src/parser/prec.rs
Normal file
385
compiler/cl-parser/src/parser/prec.rs
Normal file
@ -0,0 +1,385 @@
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//! Parses an [ExprKind] using a modified pratt parser
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//!
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//! See also: [Expr::parse], [ExprKind::parse]
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//!
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//! Implementer's note: [ExprKind::parse] is the public API for parsing [ExprKind]s.
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//! Do not call it from within this function.
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use super::{Parse, *};
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/// Parses an [ExprKind]
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pub fn exprkind(p: &mut Parser, power: u8) -> PResult<ExprKind> {
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let parsing = Parsing::ExprKind;
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// Prefix expressions
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let mut head = match p.peek_kind(Parsing::Unary)? {
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literal_like!() => Literal::parse(p)?.into(),
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path_like!() => exprkind_pathlike(p)?,
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TokenKind::Amp | TokenKind::AmpAmp => AddrOf::parse(p)?.into(),
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TokenKind::LCurly => Block::parse(p)?.into(),
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TokenKind::LBrack => exprkind_arraylike(p)?,
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TokenKind::LParen => exprkind_tuplelike(p)?,
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TokenKind::Let => Let::parse(p)?.into(),
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TokenKind::While => ExprKind::While(While::parse(p)?),
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TokenKind::If => ExprKind::If(If::parse(p)?),
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TokenKind::For => ExprKind::For(For::parse(p)?),
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TokenKind::Break => ExprKind::Break(Break::parse(p)?),
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TokenKind::Return => ExprKind::Return(Return::parse(p)?),
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TokenKind::Continue => {
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p.consume_peeked();
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ExprKind::Continue
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}
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op => {
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let (kind, prec) =
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from_prefix(op).ok_or_else(|| p.error(Unexpected(op), parsing))?;
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let ((), after) = prec.prefix().expect("should have a precedence");
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p.consume_peeked();
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Unary { kind, tail: exprkind(p, after)?.into() }.into()
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}
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};
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fn from_postfix(op: TokenKind) -> Option<Precedence> {
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Some(match op {
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TokenKind::LBrack => Precedence::Index,
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TokenKind::LParen => Precedence::Call,
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TokenKind::Dot => Precedence::Member,
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_ => None?,
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})
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}
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while let Ok(op) = p.peek_kind(parsing) {
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// Postfix expressions
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if let Some((before, ())) = from_postfix(op).and_then(Precedence::postfix) {
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if before < power {
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break;
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}
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p.consume_peeked();
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head = match op {
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TokenKind::LBrack => {
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let indices =
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sep(Expr::parse, TokenKind::Comma, TokenKind::RBrack, parsing)(p)?;
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p.match_type(TokenKind::RBrack, parsing)?;
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ExprKind::Index(Index { head: head.into(), indices })
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}
|
||||
TokenKind::LParen => {
|
||||
let exprs =
|
||||
sep(Expr::parse, TokenKind::Comma, TokenKind::RParen, parsing)(p)?;
|
||||
p.match_type(TokenKind::RParen, parsing)?;
|
||||
Binary {
|
||||
kind: BinaryKind::Call,
|
||||
parts: (head, Tuple { exprs }.into()).into(),
|
||||
}
|
||||
.into()
|
||||
}
|
||||
TokenKind::Dot => {
|
||||
let kind = MemberKind::parse(p)?;
|
||||
Member { head: Box::new(head), kind }.into()
|
||||
}
|
||||
_ => Err(p.error(Unexpected(op), parsing))?,
|
||||
};
|
||||
continue;
|
||||
}
|
||||
// infix expressions
|
||||
if let Some((kind, prec)) = from_infix(op) {
|
||||
let (before, after) = prec.infix().expect("should have a precedence");
|
||||
if before < power {
|
||||
break;
|
||||
}
|
||||
p.consume_peeked();
|
||||
|
||||
let tail = exprkind(p, after)?;
|
||||
head = Binary { kind, parts: (head, tail).into() }.into();
|
||||
continue;
|
||||
}
|
||||
|
||||
if let Some((kind, prec)) = from_modify(op) {
|
||||
let (before, after) = prec.infix().expect("should have a precedence");
|
||||
if before < power {
|
||||
break;
|
||||
}
|
||||
p.consume_peeked();
|
||||
|
||||
let tail = exprkind(p, after)?;
|
||||
head = Modify { kind, parts: (head, tail).into() }.into();
|
||||
continue;
|
||||
}
|
||||
|
||||
if let TokenKind::Eq = op {
|
||||
let (before, after) = Precedence::Assign
|
||||
.infix()
|
||||
.expect("should have a precedence");
|
||||
if before < power {
|
||||
break;
|
||||
}
|
||||
p.consume_peeked();
|
||||
|
||||
let tail = exprkind(p, after)?;
|
||||
head = Assign { parts: (head, tail).into() }.into();
|
||||
continue;
|
||||
}
|
||||
|
||||
if let TokenKind::As = op {
|
||||
let before = Precedence::Cast.level();
|
||||
if before < power {
|
||||
break;
|
||||
}
|
||||
p.consume_peeked();
|
||||
|
||||
let ty = Ty::parse(p)?;
|
||||
head = Cast { head: head.into(), ty }.into();
|
||||
continue;
|
||||
}
|
||||
|
||||
break;
|
||||
}
|
||||
|
||||
Ok(head)
|
||||
}
|
||||
|
||||
/// [Array] = '[' ([Expr] ',')* [Expr]? ']'
|
||||
///
|
||||
/// Array and ArrayRef are ambiguous until the second token,
|
||||
/// so they can't be independent subexpressions
|
||||
fn exprkind_arraylike(p: &mut Parser) -> PResult<ExprKind> {
|
||||
const P: Parsing = Parsing::Array;
|
||||
const START: TokenKind = TokenKind::LBrack;
|
||||
const END: TokenKind = TokenKind::RBrack;
|
||||
|
||||
p.match_type(START, P)?;
|
||||
let out = match p.peek_kind(P)? {
|
||||
END => Array { values: vec![] }.into(),
|
||||
_ => exprkind_array_rep(p)?,
|
||||
};
|
||||
p.match_type(END, P)?;
|
||||
Ok(out)
|
||||
}
|
||||
|
||||
/// [ArrayRep] = `[` [Expr] `;` [Expr] `]`
|
||||
fn exprkind_array_rep(p: &mut Parser) -> PResult<ExprKind> {
|
||||
const P: Parsing = Parsing::Array;
|
||||
const END: TokenKind = TokenKind::RBrack;
|
||||
|
||||
let first = Expr::parse(p)?;
|
||||
Ok(match p.peek_kind(P)? {
|
||||
TokenKind::Semi => ArrayRep {
|
||||
value: first.kind.into(),
|
||||
repeat: {
|
||||
p.consume_peeked();
|
||||
Box::new(exprkind(p, 0)?)
|
||||
},
|
||||
}
|
||||
.into(),
|
||||
TokenKind::RBrack => Array { values: vec![first] }.into(),
|
||||
TokenKind::Comma => Array {
|
||||
values: {
|
||||
p.consume_peeked();
|
||||
let mut out = vec![first];
|
||||
out.extend(sep(Expr::parse, TokenKind::Comma, END, P)(p)?);
|
||||
out
|
||||
},
|
||||
}
|
||||
.into(),
|
||||
ty => Err(p.error(Unexpected(ty), P))?,
|
||||
})
|
||||
}
|
||||
|
||||
/// [Group] = `(`([Empty](ExprKind::Empty)|[Expr]|[Tuple])`)`
|
||||
///
|
||||
/// [ExprKind::Empty] and [Group] are special cases of [Tuple]
|
||||
fn exprkind_tuplelike(p: &mut Parser) -> PResult<ExprKind> {
|
||||
p.match_type(TokenKind::LParen, Parsing::Group)?;
|
||||
let out = match p.peek_kind(Parsing::Group)? {
|
||||
TokenKind::RParen => Ok(ExprKind::Empty),
|
||||
_ => exprkind_group(p),
|
||||
};
|
||||
p.match_type(TokenKind::RParen, Parsing::Group)?;
|
||||
out
|
||||
}
|
||||
|
||||
/// [Group] = `(`([Empty](ExprKind::Empty)|[Expr]|[Tuple])`)`
|
||||
fn exprkind_group(p: &mut Parser) -> PResult<ExprKind> {
|
||||
let first = Expr::parse(p)?;
|
||||
match p.peek_kind(Parsing::Group)? {
|
||||
TokenKind::Comma => {
|
||||
let mut exprs = vec![first];
|
||||
p.consume_peeked();
|
||||
while TokenKind::RParen != p.peek_kind(Parsing::Tuple)? {
|
||||
exprs.push(Expr::parse(p)?);
|
||||
match p.peek_kind(Parsing::Tuple)? {
|
||||
TokenKind::Comma => p.consume_peeked(),
|
||||
_ => break,
|
||||
};
|
||||
}
|
||||
Ok(Tuple { exprs }.into())
|
||||
}
|
||||
_ => Ok(Group { expr: first.kind.into() }.into()),
|
||||
}
|
||||
}
|
||||
|
||||
/// Parses an expression beginning with a [Path] (i.e. [Path] or [Structor])
|
||||
fn exprkind_pathlike(p: &mut Parser) -> PResult<ExprKind> {
|
||||
let head = Path::parse(p)?;
|
||||
Ok(match p.match_type(TokenKind::Colon, Parsing::Path) {
|
||||
Ok(_) => ExprKind::Structor(structor_body(p, head)?),
|
||||
Err(_) => ExprKind::Path(head),
|
||||
})
|
||||
}
|
||||
|
||||
/// [Structor]Body = `{` ([Fielder] `,`)* [Fielder]? `}`
|
||||
fn structor_body(p: &mut Parser, to: Path) -> PResult<Structor> {
|
||||
let init = delim(
|
||||
sep(
|
||||
Fielder::parse,
|
||||
TokenKind::Comma,
|
||||
CURLIES.1,
|
||||
Parsing::Structor,
|
||||
),
|
||||
CURLIES,
|
||||
Parsing::Structor,
|
||||
)(p)?;
|
||||
|
||||
Ok(Structor { to, init })
|
||||
}
|
||||
|
||||
/// Precedence provides a total ordering among operators
|
||||
#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
|
||||
pub enum Precedence {
|
||||
Assign,
|
||||
Compare,
|
||||
Range,
|
||||
Logic,
|
||||
Bitwise,
|
||||
Shift,
|
||||
Factor,
|
||||
Term,
|
||||
Unary,
|
||||
Index,
|
||||
Cast,
|
||||
Member, // left-associative
|
||||
Call,
|
||||
}
|
||||
|
||||
impl Precedence {
|
||||
#[inline]
|
||||
pub const fn level(self) -> u8 {
|
||||
(self as u8) << 1
|
||||
}
|
||||
|
||||
pub fn prefix(self) -> Option<((), u8)> {
|
||||
match self {
|
||||
Self::Assign => Some(((), self.level())),
|
||||
Self::Unary => Some(((), self.level())),
|
||||
_ => None,
|
||||
}
|
||||
}
|
||||
|
||||
pub fn infix(self) -> Option<(u8, u8)> {
|
||||
let level = self.level();
|
||||
match self {
|
||||
Self::Unary => None,
|
||||
Self::Assign => Some((level + 1, level)),
|
||||
_ => Some((level, level + 1)),
|
||||
}
|
||||
}
|
||||
|
||||
pub fn postfix(self) -> Option<(u8, ())> {
|
||||
match self {
|
||||
Self::Index | Self::Call | Self::Member => Some((self.level(), ())),
|
||||
_ => None,
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
impl From<ModifyKind> for Precedence {
|
||||
fn from(_value: ModifyKind) -> Self {
|
||||
Precedence::Assign
|
||||
}
|
||||
}
|
||||
|
||||
impl From<BinaryKind> for Precedence {
|
||||
fn from(value: BinaryKind) -> Self {
|
||||
use BinaryKind as Op;
|
||||
match value {
|
||||
Op::Call => Precedence::Call,
|
||||
Op::Mul | Op::Div | Op::Rem => Precedence::Term,
|
||||
Op::Add | Op::Sub => Precedence::Factor,
|
||||
Op::Shl | Op::Shr => Precedence::Shift,
|
||||
Op::BitAnd | Op::BitOr | Op::BitXor => Precedence::Bitwise,
|
||||
Op::LogAnd | Op::LogOr | Op::LogXor => Precedence::Logic,
|
||||
Op::RangeExc | Op::RangeInc => Precedence::Range,
|
||||
Op::Lt | Op::LtEq | Op::Equal | Op::NotEq | Op::GtEq | Op::Gt => {
|
||||
Precedence::Compare
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
impl From<UnaryKind> for Precedence {
|
||||
fn from(value: UnaryKind) -> Self {
|
||||
use UnaryKind as Op;
|
||||
match value {
|
||||
Op::Loop => Precedence::Assign,
|
||||
Op::Deref | Op::Neg | Op::Not | Op::At | Op::Tilde => Precedence::Unary,
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
/// Creates helper functions for turning TokenKinds into AST operators
|
||||
macro operator($($name:ident ($takes:ident => $returns:ident) {$($t:ident => $p:ident),*$(,)?};)*) {$(
|
||||
pub fn $name (value: $takes) -> Option<($returns, Precedence)> {
|
||||
match value {
|
||||
$($takes::$t => Some(($returns::$p, Precedence::from($returns::$p))),)*
|
||||
_ => None?,
|
||||
}
|
||||
})*
|
||||
}
|
||||
|
||||
operator! {
|
||||
from_prefix (TokenKind => UnaryKind) {
|
||||
Loop => Loop,
|
||||
Star => Deref,
|
||||
Minus => Neg,
|
||||
Bang => Not,
|
||||
At => At,
|
||||
Tilde => Tilde,
|
||||
};
|
||||
|
||||
from_modify(TokenKind => ModifyKind) {
|
||||
AmpEq => And,
|
||||
BarEq => Or,
|
||||
XorEq => Xor,
|
||||
LtLtEq => Shl,
|
||||
GtGtEq => Shr,
|
||||
PlusEq => Add,
|
||||
MinusEq => Sub,
|
||||
StarEq => Mul,
|
||||
SlashEq => Div,
|
||||
RemEq => Rem,
|
||||
};
|
||||
|
||||
from_infix (TokenKind => BinaryKind) {
|
||||
Lt => Lt,
|
||||
LtEq => LtEq,
|
||||
EqEq => Equal,
|
||||
BangEq => NotEq,
|
||||
GtEq => GtEq,
|
||||
Gt => Gt,
|
||||
DotDot => RangeExc,
|
||||
DotDotEq => RangeInc,
|
||||
AmpAmp => LogAnd,
|
||||
BarBar => LogOr,
|
||||
XorXor => LogXor,
|
||||
Amp => BitAnd,
|
||||
Bar => BitOr,
|
||||
Xor => BitXor,
|
||||
LtLt => Shl,
|
||||
GtGt => Shr,
|
||||
Plus => Add,
|
||||
Minus => Sub,
|
||||
Star => Mul,
|
||||
Slash => Div,
|
||||
Rem => Rem,
|
||||
};
|
||||
}
|
||||
Loading…
Reference in New Issue
Block a user