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authorValentin Popov <valentin@popov.link>2024-01-08 00:21:28 +0300
committerValentin Popov <valentin@popov.link>2024-01-08 00:21:28 +0300
commit1b6a04ca5504955c571d1c97504fb45ea0befee4 (patch)
tree7579f518b23313e8a9748a88ab6173d5e030b227 /vendor/syn/src/stmt.rs
parent5ecd8cf2cba827454317368b68571df0d13d7842 (diff)
downloadfparkan-1b6a04ca5504955c571d1c97504fb45ea0befee4.tar.xz
fparkan-1b6a04ca5504955c571d1c97504fb45ea0befee4.zip
Initial vendor packages
Signed-off-by: Valentin Popov <valentin@popov.link>
Diffstat (limited to 'vendor/syn/src/stmt.rs')
-rw-r--r--vendor/syn/src/stmt.rs452
1 files changed, 452 insertions, 0 deletions
diff --git a/vendor/syn/src/stmt.rs b/vendor/syn/src/stmt.rs
new file mode 100644
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+use super::*;
+
+ast_struct! {
+ /// A braced block containing Rust statements.
+ #[cfg_attr(doc_cfg, doc(cfg(feature = "full")))]
+ pub struct Block {
+ pub brace_token: token::Brace,
+ /// Statements in a block
+ pub stmts: Vec<Stmt>,
+ }
+}
+
+ast_enum! {
+ /// A statement, usually ending in a semicolon.
+ #[cfg_attr(doc_cfg, doc(cfg(feature = "full")))]
+ pub enum Stmt {
+ /// A local (let) binding.
+ Local(Local),
+
+ /// An item definition.
+ Item(Item),
+
+ /// Expression, with or without trailing semicolon.
+ Expr(Expr, Option<Token![;]>),
+
+ /// A macro invocation in statement position.
+ ///
+ /// Syntactically it's ambiguous which other kind of statement this
+ /// macro would expand to. It can be any of local variable (`let`),
+ /// item, or expression.
+ Macro(StmtMacro),
+ }
+}
+
+ast_struct! {
+ /// A local `let` binding: `let x: u64 = s.parse()?`.
+ #[cfg_attr(doc_cfg, doc(cfg(feature = "full")))]
+ pub struct Local {
+ pub attrs: Vec<Attribute>,
+ pub let_token: Token![let],
+ pub pat: Pat,
+ pub init: Option<LocalInit>,
+ pub semi_token: Token![;],
+ }
+}
+
+ast_struct! {
+ /// The expression assigned in a local `let` binding, including optional
+ /// diverging `else` block.
+ ///
+ /// `LocalInit` represents `= s.parse()?` in `let x: u64 = s.parse()?` and
+ /// `= r else { return }` in `let Ok(x) = r else { return }`.
+ #[cfg_attr(doc_cfg, doc(cfg(feature = "full")))]
+ pub struct LocalInit {
+ pub eq_token: Token![=],
+ pub expr: Box<Expr>,
+ pub diverge: Option<(Token![else], Box<Expr>)>,
+ }
+}
+
+ast_struct! {
+ /// A macro invocation in statement position.
+ ///
+ /// Syntactically it's ambiguous which other kind of statement this macro
+ /// would expand to. It can be any of local variable (`let`), item, or
+ /// expression.
+ #[cfg_attr(doc_cfg, doc(cfg(feature = "full")))]
+ pub struct StmtMacro {
+ pub attrs: Vec<Attribute>,
+ pub mac: Macro,
+ pub semi_token: Option<Token![;]>,
+ }
+}
+
+#[cfg(feature = "parsing")]
+pub(crate) mod parsing {
+ use super::*;
+ use crate::parse::discouraged::Speculative as _;
+ use crate::parse::{Parse, ParseStream, Result};
+ use proc_macro2::TokenStream;
+
+ struct AllowNoSemi(bool);
+
+ impl Block {
+ /// Parse the body of a block as zero or more statements, possibly
+ /// including one trailing expression.
+ ///
+ /// # Example
+ ///
+ /// ```
+ /// use syn::{braced, token, Attribute, Block, Ident, Result, Stmt, Token};
+ /// use syn::parse::{Parse, ParseStream};
+ ///
+ /// // Parse a function with no generics or parameter list.
+ /// //
+ /// // fn playground {
+ /// // let mut x = 1;
+ /// // x += 1;
+ /// // println!("{}", x);
+ /// // }
+ /// struct MiniFunction {
+ /// attrs: Vec<Attribute>,
+ /// fn_token: Token![fn],
+ /// name: Ident,
+ /// brace_token: token::Brace,
+ /// stmts: Vec<Stmt>,
+ /// }
+ ///
+ /// impl Parse for MiniFunction {
+ /// fn parse(input: ParseStream) -> Result<Self> {
+ /// let outer_attrs = input.call(Attribute::parse_outer)?;
+ /// let fn_token: Token![fn] = input.parse()?;
+ /// let name: Ident = input.parse()?;
+ ///
+ /// let content;
+ /// let brace_token = braced!(content in input);
+ /// let inner_attrs = content.call(Attribute::parse_inner)?;
+ /// let stmts = content.call(Block::parse_within)?;
+ ///
+ /// Ok(MiniFunction {
+ /// attrs: {
+ /// let mut attrs = outer_attrs;
+ /// attrs.extend(inner_attrs);
+ /// attrs
+ /// },
+ /// fn_token,
+ /// name,
+ /// brace_token,
+ /// stmts,
+ /// })
+ /// }
+ /// }
+ /// ```
+ #[cfg_attr(doc_cfg, doc(cfg(feature = "parsing")))]
+ pub fn parse_within(input: ParseStream) -> Result<Vec<Stmt>> {
+ let mut stmts = Vec::new();
+ loop {
+ while let semi @ Some(_) = input.parse()? {
+ stmts.push(Stmt::Expr(Expr::Verbatim(TokenStream::new()), semi));
+ }
+ if input.is_empty() {
+ break;
+ }
+ let stmt = parse_stmt(input, AllowNoSemi(true))?;
+ let requires_semicolon = match &stmt {
+ Stmt::Expr(stmt, None) => expr::requires_terminator(stmt),
+ Stmt::Macro(stmt) => {
+ stmt.semi_token.is_none() && !stmt.mac.delimiter.is_brace()
+ }
+ Stmt::Local(_) | Stmt::Item(_) | Stmt::Expr(_, Some(_)) => false,
+ };
+ stmts.push(stmt);
+ if input.is_empty() {
+ break;
+ } else if requires_semicolon {
+ return Err(input.error("unexpected token, expected `;`"));
+ }
+ }
+ Ok(stmts)
+ }
+ }
+
+ #[cfg_attr(doc_cfg, doc(cfg(feature = "parsing")))]
+ impl Parse for Block {
+ fn parse(input: ParseStream) -> Result<Self> {
+ let content;
+ Ok(Block {
+ brace_token: braced!(content in input),
+ stmts: content.call(Block::parse_within)?,
+ })
+ }
+ }
+
+ #[cfg_attr(doc_cfg, doc(cfg(feature = "parsing")))]
+ impl Parse for Stmt {
+ fn parse(input: ParseStream) -> Result<Self> {
+ let allow_nosemi = AllowNoSemi(false);
+ parse_stmt(input, allow_nosemi)
+ }
+ }
+
+ fn parse_stmt(input: ParseStream, allow_nosemi: AllowNoSemi) -> Result<Stmt> {
+ let begin = input.fork();
+ let attrs = input.call(Attribute::parse_outer)?;
+
+ // brace-style macros; paren and bracket macros get parsed as
+ // expression statements.
+ let ahead = input.fork();
+ let mut is_item_macro = false;
+ if let Ok(path) = ahead.call(Path::parse_mod_style) {
+ if ahead.peek(Token![!]) {
+ if ahead.peek2(Ident) || ahead.peek2(Token![try]) {
+ is_item_macro = true;
+ } else if ahead.peek2(token::Brace)
+ && !(ahead.peek3(Token![.]) || ahead.peek3(Token![?]))
+ {
+ input.advance_to(&ahead);
+ return stmt_mac(input, attrs, path).map(Stmt::Macro);
+ }
+ }
+ }
+
+ if input.peek(Token![let]) && !input.peek(token::Group) {
+ stmt_local(input, attrs).map(Stmt::Local)
+ } else if input.peek(Token![pub])
+ || input.peek(Token![crate]) && !input.peek2(Token![::])
+ || input.peek(Token![extern])
+ || input.peek(Token![use])
+ || input.peek(Token![static])
+ && (input.peek2(Token![mut])
+ || input.peek2(Ident)
+ && !(input.peek2(Token![async])
+ && (input.peek3(Token![move]) || input.peek3(Token![|]))))
+ || input.peek(Token![const])
+ && !(input.peek2(token::Brace)
+ || input.peek2(Token![static])
+ || input.peek2(Token![async])
+ && !(input.peek3(Token![unsafe])
+ || input.peek3(Token![extern])
+ || input.peek3(Token![fn]))
+ || input.peek2(Token![move])
+ || input.peek2(Token![|]))
+ || input.peek(Token![unsafe]) && !input.peek2(token::Brace)
+ || input.peek(Token![async])
+ && (input.peek2(Token![unsafe])
+ || input.peek2(Token![extern])
+ || input.peek2(Token![fn]))
+ || input.peek(Token![fn])
+ || input.peek(Token![mod])
+ || input.peek(Token![type])
+ || input.peek(Token![struct])
+ || input.peek(Token![enum])
+ || input.peek(Token![union]) && input.peek2(Ident)
+ || input.peek(Token![auto]) && input.peek2(Token![trait])
+ || input.peek(Token![trait])
+ || input.peek(Token![default])
+ && (input.peek2(Token![unsafe]) || input.peek2(Token![impl]))
+ || input.peek(Token![impl])
+ || input.peek(Token![macro])
+ || is_item_macro
+ {
+ let item = item::parsing::parse_rest_of_item(begin, attrs, input)?;
+ Ok(Stmt::Item(item))
+ } else {
+ stmt_expr(input, allow_nosemi, attrs)
+ }
+ }
+
+ fn stmt_mac(input: ParseStream, attrs: Vec<Attribute>, path: Path) -> Result<StmtMacro> {
+ let bang_token: Token![!] = input.parse()?;
+ let (delimiter, tokens) = mac::parse_delimiter(input)?;
+ let semi_token: Option<Token![;]> = input.parse()?;
+
+ Ok(StmtMacro {
+ attrs,
+ mac: Macro {
+ path,
+ bang_token,
+ delimiter,
+ tokens,
+ },
+ semi_token,
+ })
+ }
+
+ fn stmt_local(input: ParseStream, attrs: Vec<Attribute>) -> Result<Local> {
+ let let_token: Token![let] = input.parse()?;
+
+ let mut pat = Pat::parse_single(input)?;
+ if input.peek(Token![:]) {
+ let colon_token: Token![:] = input.parse()?;
+ let ty: Type = input.parse()?;
+ pat = Pat::Type(PatType {
+ attrs: Vec::new(),
+ pat: Box::new(pat),
+ colon_token,
+ ty: Box::new(ty),
+ });
+ }
+
+ let init = if let Some(eq_token) = input.parse()? {
+ let eq_token: Token![=] = eq_token;
+ let expr: Expr = input.parse()?;
+
+ let diverge = if let Some(else_token) = input.parse()? {
+ let else_token: Token![else] = else_token;
+ let diverge = ExprBlock {
+ attrs: Vec::new(),
+ label: None,
+ block: input.parse()?,
+ };
+ Some((else_token, Box::new(Expr::Block(diverge))))
+ } else {
+ None
+ };
+
+ Some(LocalInit {
+ eq_token,
+ expr: Box::new(expr),
+ diverge,
+ })
+ } else {
+ None
+ };
+
+ let semi_token: Token![;] = input.parse()?;
+
+ Ok(Local {
+ attrs,
+ let_token,
+ pat,
+ init,
+ semi_token,
+ })
+ }
+
+ fn stmt_expr(
+ input: ParseStream,
+ allow_nosemi: AllowNoSemi,
+ mut attrs: Vec<Attribute>,
+ ) -> Result<Stmt> {
+ let mut e = expr::parsing::expr_early(input)?;
+
+ let mut attr_target = &mut e;
+ loop {
+ attr_target = match attr_target {
+ Expr::Assign(e) => &mut e.left,
+ Expr::Binary(e) => &mut e.left,
+ Expr::Cast(e) => &mut e.expr,
+ Expr::Array(_)
+ | Expr::Async(_)
+ | Expr::Await(_)
+ | Expr::Block(_)
+ | Expr::Break(_)
+ | Expr::Call(_)
+ | Expr::Closure(_)
+ | Expr::Const(_)
+ | Expr::Continue(_)
+ | Expr::Field(_)
+ | Expr::ForLoop(_)
+ | Expr::Group(_)
+ | Expr::If(_)
+ | Expr::Index(_)
+ | Expr::Infer(_)
+ | Expr::Let(_)
+ | Expr::Lit(_)
+ | Expr::Loop(_)
+ | Expr::Macro(_)
+ | Expr::Match(_)
+ | Expr::MethodCall(_)
+ | Expr::Paren(_)
+ | Expr::Path(_)
+ | Expr::Range(_)
+ | Expr::Reference(_)
+ | Expr::Repeat(_)
+ | Expr::Return(_)
+ | Expr::Struct(_)
+ | Expr::Try(_)
+ | Expr::TryBlock(_)
+ | Expr::Tuple(_)
+ | Expr::Unary(_)
+ | Expr::Unsafe(_)
+ | Expr::While(_)
+ | Expr::Yield(_)
+ | Expr::Verbatim(_) => break,
+ };
+ }
+ attrs.extend(attr_target.replace_attrs(Vec::new()));
+ attr_target.replace_attrs(attrs);
+
+ let semi_token: Option<Token![;]> = input.parse()?;
+
+ match e {
+ Expr::Macro(ExprMacro { attrs, mac })
+ if semi_token.is_some() || mac.delimiter.is_brace() =>
+ {
+ return Ok(Stmt::Macro(StmtMacro {
+ attrs,
+ mac,
+ semi_token,
+ }));
+ }
+ _ => {}
+ }
+
+ if semi_token.is_some() {
+ Ok(Stmt::Expr(e, semi_token))
+ } else if allow_nosemi.0 || !expr::requires_terminator(&e) {
+ Ok(Stmt::Expr(e, None))
+ } else {
+ Err(input.error("expected semicolon"))
+ }
+ }
+}
+
+#[cfg(feature = "printing")]
+mod printing {
+ use super::*;
+ use proc_macro2::TokenStream;
+ use quote::{ToTokens, TokenStreamExt};
+
+ #[cfg_attr(doc_cfg, doc(cfg(feature = "printing")))]
+ impl ToTokens for Block {
+ fn to_tokens(&self, tokens: &mut TokenStream) {
+ self.brace_token.surround(tokens, |tokens| {
+ tokens.append_all(&self.stmts);
+ });
+ }
+ }
+
+ #[cfg_attr(doc_cfg, doc(cfg(feature = "printing")))]
+ impl ToTokens for Stmt {
+ fn to_tokens(&self, tokens: &mut TokenStream) {
+ match self {
+ Stmt::Local(local) => local.to_tokens(tokens),
+ Stmt::Item(item) => item.to_tokens(tokens),
+ Stmt::Expr(expr, semi) => {
+ expr.to_tokens(tokens);
+ semi.to_tokens(tokens);
+ }
+ Stmt::Macro(mac) => mac.to_tokens(tokens),
+ }
+ }
+ }
+
+ #[cfg_attr(doc_cfg, doc(cfg(feature = "printing")))]
+ impl ToTokens for Local {
+ fn to_tokens(&self, tokens: &mut TokenStream) {
+ expr::printing::outer_attrs_to_tokens(&self.attrs, tokens);
+ self.let_token.to_tokens(tokens);
+ self.pat.to_tokens(tokens);
+ if let Some(init) = &self.init {
+ init.eq_token.to_tokens(tokens);
+ init.expr.to_tokens(tokens);
+ if let Some((else_token, diverge)) = &init.diverge {
+ else_token.to_tokens(tokens);
+ diverge.to_tokens(tokens);
+ }
+ }
+ self.semi_token.to_tokens(tokens);
+ }
+ }
+
+ #[cfg_attr(doc_cfg, doc(cfg(feature = "printing")))]
+ impl ToTokens for StmtMacro {
+ fn to_tokens(&self, tokens: &mut TokenStream) {
+ expr::printing::outer_attrs_to_tokens(&self.attrs, tokens);
+ self.mac.to_tokens(tokens);
+ self.semi_token.to_tokens(tokens);
+ }
+ }
+}