Struct Ident

pub struct Ident {
    pub span: Span,
    pub ctxt: SyntaxContext,
    pub sym: Atom,
    pub optional: bool,
}

Available on crate features __ecma and ecma_ast only.

A complete identifier with span.

Identifier of swc consists of two parts. The first one is symbol, which is stored using an interned string, Atom . The second one is SyntaxContext, which can be used to distinguish identifier with same symbol.

Let me explain this with an example.

let a = 5
{
    let a = 3;
}

In the code above, there are two variables with the symbol a.

Other compilers typically uses type like Scope, and store them nested, but in rust, type like Scope requires [Arc<Mutex>] so swc uses different approach. Instead of passing scopes, swc annotates two variables with different tag, which is named SyntaxContext. The notation for the syntax context is #n where n is a number. e.g. foo#1

For the example above, after applying resolver pass, it becomes.

let a#1 = 5
{
    let a#2 = 3;
}

Thanks to the tag we attached, we can now distinguish them.

(Atom, SyntaxContext)

See Id, which is a type alias for this.

This can be used to store all variables in a module to single hash map.

Comparison

While comparing two identifiers, you can use .to_id().

HashMap

There’s a type named Id which only contains minimal information to distinguish identifiers.

Fields

span: Span

ctxt: SyntaxContext

sym: Atom

optional: bool

TypeScript only. Used in case of an optional parameter.

Implementations

impl Ident

pub fn within_ignored_ctxt<F, Ret>(op: F) -> Ret

where F: FnOnce() -> Ret,

In op, EqIgnoreSpan of Ident will ignore the syntax context.

pub fn without_loc(self) -> Ident

Preserve syntax context while drop span.lo and span.hi.

pub fn to_id(&self) -> (Atom, SyntaxContext)

Creates Id using Atom and SyntaxContext of self.

pub fn is_valid_start(c: char) -> bool

Returns true if c is a valid character for an identifier start.

pub fn is_valid_continue(c: char) -> bool

Returns true if c is a valid character for an identifier part after start.

pub fn verify_symbol(s: &str) -> Result<(), String>

Alternative for toIdentifier of babel.

Returns Ok if it’s a valid identifier and Err if it’s not valid. The returned Err contains the valid symbol.

pub fn with_prefix(&self, prefix: &str) -> Ident

Create a new identifier with the given prefix.

pub fn into_private(self) -> Ident

Create a private identifier that is unique in the file, but with the same symbol.

pub fn is_dummy(&self) -> bool

pub fn with_pos(self, lo: BytePos, hi: BytePos) -> Ident

Create a new identifier with the given position.

impl Ident

pub const fn new(sym: Atom, span: Span, ctxt: SyntaxContext) -> Ident

pub fn new_private(sym: Atom, span: Span) -> Ident

pub const fn new_no_ctxt(sym: Atom, span: Span) -> Ident

Trait Implementations

impl Archive for Ident

type Archived = ArchivedIdent

The archived representation of this type.

type Resolver = IdentResolver

The resolver for this type. It must contain all the additional information from serializing needed to make the archived type from the normal type.

unsafe fn resolve( &self, pos: usize, resolver: <Ident as Archive>::Resolver, out: *mut <Ident as Archive>::Archived, )

Creates the archived version of this value at the given position and writes it to the given output.

impl AsRef<str> for Ident

fn as_ref(&self) -> &str

Converts this type into a shared reference of the (usually inferred) input type.

impl AstNode for Ident

const TYPE: &'static str = "Identifier"

impl Clone for Ident

fn clone(&self) -> Ident

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Ident

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.

impl Default for Ident

fn default() -> Ident

Returns the “default value” for a type.

impl<'de> Deserialize<'de> for Ident

fn deserialize<__D>( __deserializer: __D, ) -> Result<Ident, <__D as Deserializer<'de>>::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl<__D> Deserialize<Ident, __D> for <Ident as Archive>::Archived

where __D: Fallible + ?Sized,

fn deserialize( &self, deserializer: &mut __D, ) -> Result<Ident, <__D as Fallible>::Error>

Deserializes using the given deserializer

impl Display for Ident

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.

impl EqIgnoreSpan for Ident

fn eq_ignore_span(&self, other: &Ident) -> bool

impl EsReserved for Ident

fn is_reserved(&self) -> bool

fn is_reserved_in_strict_mode(&self, is_module: bool) -> bool

fn is_reserved_in_strict_bind(&self) -> bool

fn is_reserved_in_es3(&self) -> bool

fn is_reserved_in_any(&self) -> bool

impl<V> FoldWith<V> for Ident

where V: Fold + ?Sized,

fn fold_with(self, visitor: &mut V) -> Ident

Calls Fold::fold_ident with self.

fn fold_children_with(self, visitor: &mut V) -> Ident

Visit children nodes of self`` with visitor`.

impl From<&BindingIdent> for Ident

fn from(bi: &BindingIdent) -> Ident

Converts to this type from the input type.

impl<'ast> From<&'ast Ident> for NodeRef<'ast>

fn from(node: &'ast Ident) -> NodeRef<'ast>

Converts to this type from the input type.

impl From<&str> for Ident

fn from(src: &str) -> Ident

Converts to this type from the input type.

impl From<(Atom, Span)> for Ident

fn from(_: (Atom, Span)) -> Ident

Converts to this type from the input type.

impl From<(Atom, SyntaxContext)> for Ident

fn from(id: (Atom, SyntaxContext)) -> Ident

Converts to this type from the input type.

impl From<Atom> for Ident

fn from(bi: Atom) -> Ident

Converts to this type from the input type.

impl From<BindingIdent> for Ident

fn from(bi: BindingIdent) -> Ident

Converts to this type from the input type.

impl From<Cow<'_, str>> for Ident

fn from(src: Cow<'_, str>) -> Ident

Converts to this type from the input type.

impl From<Ident> for (Atom, SyntaxContext)

fn from(i: Ident) -> (Atom, SyntaxContext)

Converts to this type from the input type.

impl From<Ident> for AssignTarget

fn from(src: Ident) -> AssignTarget

Converts to this type from the input type.

impl From<Ident> for BindingIdent

fn from(id: Ident) -> BindingIdent

Converts to this type from the input type.

impl From<Ident> for Box<Expr>

fn from(src: Ident) -> Box<Expr>

Converts to this type from the input type.

impl From<Ident> for Box<Pat>

fn from(src: Ident) -> Box<Pat>

Converts to this type from the input type.

impl From<Ident> for Expr

fn from(v: Ident) -> Expr

Converts to this type from the input type.

impl From<Ident> for IdentName

fn from(i: Ident) -> IdentName

Converts to this type from the input type.

impl From<Ident> for JSXElementName

fn from(v: Ident) -> JSXElementName

Converts to this type from the input type.

impl From<Ident> for JSXObject

fn from(v: Ident) -> JSXObject

Converts to this type from the input type.

impl From<Ident> for Key

fn from(src: Ident) -> Key

Converts to this type from the input type.

impl From<Ident> for ModuleExportName

fn from(v: Ident) -> ModuleExportName

Converts to this type from the input type.

impl From<Ident> for Param

fn from(src: Ident) -> Param

Converts to this type from the input type.

impl From<Ident> for Pat

fn from(src: Ident) -> Pat

Converts to this type from the input type.

impl From<Ident> for Prop

fn from(v: Ident) -> Prop

Converts to this type from the input type.

impl From<Ident> for PropName

fn from(src: Ident) -> PropName

Converts to this type from the input type.

impl From<Ident> for SimpleAssignTarget

fn from(src: Ident) -> SimpleAssignTarget

Converts to this type from the input type.

impl From<Ident> for TsEntityName

fn from(v: Ident) -> TsEntityName

Converts to this type from the input type.

impl From<Ident> for TsEnumMemberId

fn from(v: Ident) -> TsEnumMemberId

Converts to this type from the input type.

impl From<Ident> for TsModuleName

fn from(v: Ident) -> TsModuleName

Converts to this type from the input type.

impl From<Ident> for TsThisTypeOrIdent

fn from(v: Ident) -> TsThisTypeOrIdent

Converts to this type from the input type.

impl From<IdentName> for Ident

fn from(i: IdentName) -> Ident

Converts to this type from the input type.

impl From<String> for Ident

fn from(src: String) -> Ident

Converts to this type from the input type.

impl Hash for Ident

fn hash<__H>(&self, state: &mut __H)

where __H: Hasher,

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl IdentLike for Ident

fn from_ident(i: &Ident) -> Ident

fn to_id(&self) -> (Atom, SyntaxContext)

fn into_id(self) -> (Atom, SyntaxContext)

impl Node for Ident

fn emit_with<W, S>(&self, e: &mut Emitter<'_, W, S>) -> Result<(), Error>

where S: SourceMapper + SourceMapperExt, W: WriteJs,

impl PartialEq for Ident

fn eq(&self, other: &Ident) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl<__S> Serialize<__S> for Ident

where __S: Fallible + ScratchSpace + Serializer + ?Sized,

fn serialize( &self, serializer: &mut __S, ) -> Result<<Ident as Archive>::Resolver, <__S as Fallible>::Error>

Writes the dependencies for the object and returns a resolver that can create the archived type.

impl Serialize for Ident

fn serialize<__S>( &self, __serializer: __S, ) -> Result<<__S as Serializer>::Ok, <__S as Serializer>::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl Spanned for Ident

fn span(&self) -> Span

Get span of self.

fn span_lo(&self) -> BytePos

fn span_hi(&self) -> BytePos

impl StartsWithAlphaNum for Ident

fn starts_with_alpha_num(&self) -> bool

impl Take for Ident

fn dummy() -> Ident

Create a dummy value of this type.

fn take(&mut self) -> Self

fn map_with_mut<F>(&mut self, op: F)

where F: FnOnce(Self) -> Self,

Mutate self using op, which accepts owned data.

impl<V> VisitMutWith<V> for Ident

where V: VisitMut + ?Sized,

fn visit_mut_with(&mut self, visitor: &mut V)

Calls VisitMut::visit_mut_ident with self.

fn visit_mut_children_with(&mut self, visitor: &mut V)

Visit children nodes of self`` with visitor`.

impl<V> VisitWith<V> for Ident

where V: Visit + ?Sized,

fn visit_with(&self, visitor: &mut V)

Calls Visit::visit_ident with self.

fn visit_children_with(&self, visitor: &mut V)

Visit children nodes of self`` with visitor`.

impl Eq for Ident

impl StructuralPartialEq for Ident