#[repr(C)]pub struct DirectiveLiteral<'gc> {
pub metadata: NodeMetadata<'gc>,
pub value: Cell<NodeString>,
}Expand description
The DirectiveLiteral AST node.
Fields§
§metadata: NodeMetadata<'gc>Source range, debug location, paren count, and node id.
value: Cell<NodeString>ESTree value property.
Implementations§
Source§impl<'gc> DirectiveLiteral<'gc>
impl<'gc> DirectiveLiteral<'gc>
Sourcepub fn new(metadata: NodeMetadata<'gc>, value: NodeString) -> Self
pub fn new(metadata: NodeMetadata<'gc>, value: NodeString) -> Self
Build DirectiveLiteral from its metadata and ESTree.def fields.
Sourcepub fn try_value_str<'a>(&self, gc: &'a GCLock<'_, '_>) -> Option<&'a str>
pub fn try_value_str<'a>(&self, gc: &'a GCLock<'_, '_>) -> Option<&'a str>
The value string value as UTF-8, or None if it has no UTF-8 form.
A JS string value is a sequence of UTF-16 code units, so it may legally
contain an unpaired surrogate ("\uD800" parses, and is not an
error). That, and only that, is what None reports: the value is
intact, it simply cannot be spelled in UTF-8. Read it losslessly with
GCLock::bytes.
Only an unpaired surrogate is unrepresentable. A WTF-8 surrogate
pair is not: the lexer interns an astral character in surrogate-pair
form, and it is folded back into the character it encodes, so a "😀"
literal yields Some("😀"), not None.
There is deliberately no plain value_str: an unrepresentable
identifier means something is broken, but an unrepresentable string
literal is legal JS, and a codegen or refactoring tool that let U+FFFD
be substituted here would silently rewrite the user’s program. Reach for
Self::value_str_lossy only when a best-effort rendering is what you
want.
Valid UTF-8 is borrowed from the atom’s own bytes and allocates nothing;
folding a surrogate pair allocates once per atom, cached in the context.
The returned &str borrows from gc, not from self.
Sourcepub fn value_str_lossy<'a>(&self, gc: &'a GCLock<'_, '_>) -> &'a str
pub fn value_str_lossy<'a>(&self, gc: &'a GCLock<'_, '_>) -> &'a str
The value string value as UTF-8, substituting U+FFFD for anything
unrepresentable.
This is lossy. A JS string value may legally contain an unpaired
surrogate ("\uD800" parses), which has no UTF-8 form; each one becomes
exactly one U+FFFD here. Do not use this to re-emit source: a codegen or
refactoring tool would silently rewrite the user’s program.
Only an unpaired surrogate is unrepresentable. A WTF-8 surrogate
pair is not: the lexer interns an astral character in surrogate-pair
form, and it is folded back into the character it encodes, so a "😀"
literal comes out intact.
Use Self::try_value_str or
GCLock::bytes when the exact value
matters. The returned &str borrows from gc, not from self.