Struct proc_macro2::Span
source · pub struct Span { /* private fields */ }Expand description
A region of source code, along with macro expansion information.
Implementations§
source§impl Span
impl Span
sourcepub fn call_site() -> Self
pub fn call_site() -> Self
The span of the invocation of the current procedural macro.
Identifiers created with this span will be resolved as if they were written directly at the macro call location (call-site hygiene) and other code at the macro call site will be able to refer to them as well.
sourcepub fn mixed_site() -> Self
pub fn mixed_site() -> Self
The span located at the invocation of the procedural macro, but with
local variables, labels, and $crate resolved at the definition site
of the macro. This is the same hygiene behavior as macro_rules.
This function requires Rust 1.45 or later.
sourcepub fn resolved_at(&self, other: Span) -> Span
pub fn resolved_at(&self, other: Span) -> Span
Creates a new span with the same line/column information as self but
that resolves symbols as though it were at other.
sourcepub fn located_at(&self, other: Span) -> Span
pub fn located_at(&self, other: Span) -> Span
Creates a new span with the same name resolution behavior as self but
with the line/column information of other.
sourcepub fn unwrap(self) -> Span
pub fn unwrap(self) -> Span
Convert proc_macro2::Span to proc_macro::Span.
This method is available when building with a nightly compiler, or when building with rustc 1.29+ without semver exempt features.
Panics
Panics if called from outside of a procedural macro. Unlike
proc_macro2::Span, the proc_macro::Span type can only exist within
the context of a procedural macro invocation.
sourcepub fn start(&self) -> LineColumn
pub fn start(&self) -> LineColumn
Get the starting line/column in the source file for this span.
This method requires the "span-locations" feature to be enabled.
When executing in a procedural macro context, the returned line/column are only meaningful if compiled with a nightly toolchain. The stable toolchain does not have this information available. When executing outside of a procedural macro, such as main.rs or build.rs, the line/column are always meaningful regardless of toolchain.
sourcepub fn end(&self) -> LineColumn
pub fn end(&self) -> LineColumn
Get the ending line/column in the source file for this span.
This method requires the "span-locations" feature to be enabled.
When executing in a procedural macro context, the returned line/column are only meaningful if compiled with a nightly toolchain. The stable toolchain does not have this information available. When executing outside of a procedural macro, such as main.rs or build.rs, the line/column are always meaningful regardless of toolchain.
sourcepub fn join(&self, other: Span) -> Option<Span>
pub fn join(&self, other: Span) -> Option<Span>
Create a new span encompassing self and other.
Returns None if self and other are from different files.
Warning: the underlying proc_macro::Span::join method is
nightly-only. When called from within a procedural macro not using a
nightly compiler, this method will always return None.
sourcepub fn source_text(&self) -> Option<String>
pub fn source_text(&self) -> Option<String>
Returns the source text behind a span. This preserves the original source code, including spaces and comments. It only returns a result if the span corresponds to real source code.
Note: The observable result of a macro should only rely on the tokens and not on this source text. The result of this function is a best effort to be used for diagnostics only.