pub struct Ident {
    pub span: Span,
    pub sym: JsWord,
    pub optional: bool,
}
Expand description

A complete identifier with span.

Identifier of swc consists of two parts. The first one is symbol, which is stored using an interned string, JsWord . 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.

(JsWord, 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: Spansym: JsWordoptional: bool

TypeScript only. Used in case of an optional parameter.

Implementations

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

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

Creates Id using JsWord and SyntaxContext of self.

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

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

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.

Trait Implementations

The archived representation of this type. Read more
The resolver for this type. It must contain all the additional information from serializing needed to make the archived type from the normal type. Read more
Creates the archived version of this value at the given position and writes it to the given output. Read more
Converts this type into a shared reference of the (usually inferred) input type.
Returns a copy of the value. Read more
Performs copy-assignment from source. Read more
Formats the value using the given formatter. Read more
Deserialize this value from the given Serde deserializer. Read more
Deserializes using the given deserializer
Formats the value using the given formatter. Read more
Converts to this type from the input type.
Converts to this type from the input type.
Converts to this type from the input type.
Converts to this type from the input type.
Converts to this type from the input type.
Converts to this type from the input type.
Converts to this type from the input type.
Converts to this type from the input type.
Converts to this type from the input type.
Converts to this type from the input type.
Converts to this type from the input type.
Converts to this type from the input type.
Converts to this type from the input type.
Converts to this type from the input type.
Converts to this type from the input type.
Converts to this type from the input type.
Converts to this type from the input type.
Converts to this type from the input type.
Converts to this type from the input type.
Converts to this type from the input type.
Converts to this type from the input type.
Feeds this value into the given Hasher. Read more
Feeds a slice of this type into the given Hasher. Read more
This method tests for self and other values to be equal, and is used by ==. Read more
This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason. Read more
Writes the dependencies for the object and returns a resolver that can create the archived type. Read more
Serialize this value into the given Serde serializer. Read more
Get span of self.
Create a dummy value of this type.
Mutate self using op, which accepts owned data.

Auto Trait Implementations

Blanket Implementations

Gets the TypeId of self. Read more
The archived version of the pointer metadata for this type.
Converts some archived metadata to the pointer metadata for itself.
The archived counterpart of this type. Unlike Archive, it may be unsized. Read more
The resolver for the metadata of this type. Read more
Creates the archived version of the metadata for this value at the given position and writes it to the given output. Read more
Resolves a relative pointer to this value with the given from and to and writes it to the given output. Read more
Immutably borrows from an owned value. Read more
Mutably borrows from an owned value. Read more
Deserializes using the given deserializer

Returns the argument unchanged.

Instruments this type with the provided Span, returning an Instrumented wrapper. Read more
Instruments this type with the current Span, returning an Instrumented wrapper. Read more

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

The type for metadata in pointers and references to Self.
Writes the object and returns the position of the archived type.
Serializes the metadata for the given type.
The resulting type after obtaining ownership.
Creates owned data from borrowed data, usually by cloning. Read more
Uses borrowed data to replace owned data, usually by cloning. Read more
Converts the given value to a String. Read more
The type returned in the event of a conversion error.
Performs the conversion.
The type returned in the event of a conversion error.
Performs the conversion.
Attaches the provided Subscriber to this type, returning a WithDispatch wrapper. Read more
Attaches the current default Subscriber to this type, returning a WithDispatch wrapper. Read more