68 lines
2.4 KiB
Rust
68 lines
2.4 KiB
Rust
//! Proc Macro Expander stub
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use base_db::{CrateId, ProcMacroExpansionError, ProcMacroId, ProcMacroKind};
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use mbe::ExpandResult;
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use crate::db::AstDatabase;
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#[derive(Debug, Clone, Copy, Eq, PartialEq, Hash)]
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pub struct ProcMacroExpander {
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krate: CrateId,
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proc_macro_id: Option<ProcMacroId>,
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}
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impl ProcMacroExpander {
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pub fn new(krate: CrateId, proc_macro_id: ProcMacroId) -> Self {
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Self { krate, proc_macro_id: Some(proc_macro_id) }
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}
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pub fn dummy(krate: CrateId) -> Self {
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// FIXME: Should store the name for better errors
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Self { krate, proc_macro_id: None }
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}
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pub fn is_dummy(&self) -> bool {
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self.proc_macro_id.is_none()
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}
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pub fn expand(
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self,
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db: &dyn AstDatabase,
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calling_crate: CrateId,
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tt: &tt::Subtree,
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attr_arg: Option<&tt::Subtree>,
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) -> ExpandResult<tt::Subtree> {
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match self.proc_macro_id {
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Some(id) => {
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let krate_graph = db.crate_graph();
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let proc_macro = match krate_graph[self.krate].proc_macro.get(id.0 as usize) {
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Some(proc_macro) => proc_macro,
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None => return ExpandResult::str_err("No proc-macro found.".to_string()),
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};
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// Proc macros have access to the environment variables of the invoking crate.
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let env = &krate_graph[calling_crate].env;
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match proc_macro.expander.expand(tt, attr_arg, env) {
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Ok(t) => ExpandResult::ok(t),
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Err(err) => match err {
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// Don't discard the item in case something unexpected happened while expanding attributes
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ProcMacroExpansionError::System(text)
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if proc_macro.kind == ProcMacroKind::Attr =>
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{
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ExpandResult {
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value: tt.clone(),
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err: Some(mbe::ExpandError::Other(text.into())),
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}
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}
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ProcMacroExpansionError::System(text)
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| ProcMacroExpansionError::Panic(text) => {
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ExpandResult::only_err(mbe::ExpandError::Other(text.into()))
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}
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},
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}
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}
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None => ExpandResult::only_err(mbe::ExpandError::UnresolvedProcMacro),
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}
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}
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}
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