252 lines
7.5 KiB
Rust
252 lines
7.5 KiB
Rust
//! Builtin derives.
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use tracing::debug;
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use syntax::{
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ast::{self, AstNode, HasGenericParams, HasModuleItem, HasName},
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match_ast,
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};
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use tt::TokenId;
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use crate::{db::AstDatabase, name, quote, ExpandError, ExpandResult, MacroCallId};
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macro_rules! register_builtin {
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( $($trait:ident => $expand:ident),* ) => {
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#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
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pub enum BuiltinDeriveExpander {
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$($trait),*
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}
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impl BuiltinDeriveExpander {
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pub fn expand(
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&self,
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db: &dyn AstDatabase,
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id: MacroCallId,
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tt: &tt::Subtree,
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) -> ExpandResult<tt::Subtree> {
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let expander = match *self {
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$( BuiltinDeriveExpander::$trait => $expand, )*
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};
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expander(db, id, tt)
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}
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fn find_by_name(name: &name::Name) -> Option<Self> {
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match name {
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$( id if id == &name::name![$trait] => Some(BuiltinDeriveExpander::$trait), )*
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_ => None,
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}
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}
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}
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};
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}
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register_builtin! {
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Copy => copy_expand,
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Clone => clone_expand,
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Default => default_expand,
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Debug => debug_expand,
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Hash => hash_expand,
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Ord => ord_expand,
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PartialOrd => partial_ord_expand,
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Eq => eq_expand,
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PartialEq => partial_eq_expand
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}
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pub fn find_builtin_derive(ident: &name::Name) -> Option<BuiltinDeriveExpander> {
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BuiltinDeriveExpander::find_by_name(ident)
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}
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struct BasicAdtInfo {
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name: tt::Ident,
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type_or_const_params: usize,
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}
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fn parse_adt(tt: &tt::Subtree) -> Result<BasicAdtInfo, ExpandError> {
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let (parsed, token_map) = mbe::token_tree_to_syntax_node(tt, mbe::TopEntryPoint::MacroItems);
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let macro_items = ast::MacroItems::cast(parsed.syntax_node()).ok_or_else(|| {
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debug!("derive node didn't parse");
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ExpandError::Other("invalid item definition".into())
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})?;
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let item = macro_items.items().next().ok_or_else(|| {
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debug!("no module item parsed");
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ExpandError::Other("no item found".into())
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})?;
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let node = item.syntax();
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let (name, params) = match_ast! {
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match node {
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ast::Struct(it) => (it.name(), it.generic_param_list()),
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ast::Enum(it) => (it.name(), it.generic_param_list()),
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ast::Union(it) => (it.name(), it.generic_param_list()),
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_ => {
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debug!("unexpected node is {:?}", node);
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return Err(ExpandError::Other("expected struct, enum or union".into()))
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},
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}
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};
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let name = name.ok_or_else(|| {
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debug!("parsed item has no name");
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ExpandError::Other("missing name".into())
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})?;
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let name_token_id =
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token_map.token_by_range(name.syntax().text_range()).unwrap_or_else(TokenId::unspecified);
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let name_token = tt::Ident { id: name_token_id, text: name.text().into() };
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let type_or_const_params =
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params.map_or(0, |type_param_list| type_param_list.type_or_const_params().count());
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Ok(BasicAdtInfo { name: name_token, type_or_const_params })
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}
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fn make_type_args(n: usize, bound: Vec<tt::TokenTree>) -> Vec<tt::TokenTree> {
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let mut result = Vec::<tt::TokenTree>::with_capacity(n * 2);
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result.push(
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tt::Leaf::Punct(tt::Punct {
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char: '<',
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spacing: tt::Spacing::Alone,
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id: tt::TokenId::unspecified(),
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})
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.into(),
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);
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for i in 0..n {
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if i > 0 {
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result.push(
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tt::Leaf::Punct(tt::Punct {
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char: ',',
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spacing: tt::Spacing::Alone,
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id: tt::TokenId::unspecified(),
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})
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.into(),
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);
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}
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result.push(
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tt::Leaf::Ident(tt::Ident {
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id: tt::TokenId::unspecified(),
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text: format!("T{}", i).into(),
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})
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.into(),
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);
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result.extend(bound.iter().cloned());
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}
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result.push(
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tt::Leaf::Punct(tt::Punct {
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char: '>',
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spacing: tt::Spacing::Alone,
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id: tt::TokenId::unspecified(),
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})
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.into(),
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);
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result
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}
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fn expand_simple_derive(tt: &tt::Subtree, trait_path: tt::Subtree) -> ExpandResult<tt::Subtree> {
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let info = match parse_adt(tt) {
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Ok(info) => info,
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Err(e) => return ExpandResult::only_err(e),
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};
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let name = info.name;
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let trait_path_clone = trait_path.token_trees.clone();
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let bound = (quote! { : ##trait_path_clone }).token_trees;
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let type_params = make_type_args(info.type_or_const_params, bound);
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let type_args = make_type_args(info.type_or_const_params, Vec::new());
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let trait_path = trait_path.token_trees;
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let expanded = quote! {
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impl ##type_params ##trait_path for #name ##type_args {}
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};
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ExpandResult::ok(expanded)
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}
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fn find_builtin_crate(db: &dyn AstDatabase, id: MacroCallId) -> tt::TokenTree {
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// FIXME: make hygiene works for builtin derive macro
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// such that $crate can be used here.
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let cg = db.crate_graph();
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let krate = db.lookup_intern_macro_call(id).krate;
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// XXX
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// All crates except core itself should have a dependency on core,
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// We detect `core` by seeing whether it doesn't have such a dependency.
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let tt = if cg[krate].dependencies.iter().any(|dep| &*dep.name == "core") {
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quote! { core }
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} else {
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cov_mark::hit!(test_copy_expand_in_core);
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quote! { crate }
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};
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tt.token_trees[0].clone()
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}
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fn copy_expand(
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db: &dyn AstDatabase,
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id: MacroCallId,
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tt: &tt::Subtree,
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) -> ExpandResult<tt::Subtree> {
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let krate = find_builtin_crate(db, id);
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expand_simple_derive(tt, quote! { #krate::marker::Copy })
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}
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fn clone_expand(
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db: &dyn AstDatabase,
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id: MacroCallId,
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tt: &tt::Subtree,
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) -> ExpandResult<tt::Subtree> {
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let krate = find_builtin_crate(db, id);
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expand_simple_derive(tt, quote! { #krate::clone::Clone })
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}
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fn default_expand(
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db: &dyn AstDatabase,
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id: MacroCallId,
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tt: &tt::Subtree,
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) -> ExpandResult<tt::Subtree> {
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let krate = find_builtin_crate(db, id);
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expand_simple_derive(tt, quote! { #krate::default::Default })
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}
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fn debug_expand(
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db: &dyn AstDatabase,
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id: MacroCallId,
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tt: &tt::Subtree,
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) -> ExpandResult<tt::Subtree> {
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let krate = find_builtin_crate(db, id);
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expand_simple_derive(tt, quote! { #krate::fmt::Debug })
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}
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fn hash_expand(
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db: &dyn AstDatabase,
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id: MacroCallId,
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tt: &tt::Subtree,
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) -> ExpandResult<tt::Subtree> {
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let krate = find_builtin_crate(db, id);
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expand_simple_derive(tt, quote! { #krate::hash::Hash })
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}
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fn eq_expand(db: &dyn AstDatabase, id: MacroCallId, tt: &tt::Subtree) -> ExpandResult<tt::Subtree> {
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let krate = find_builtin_crate(db, id);
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expand_simple_derive(tt, quote! { #krate::cmp::Eq })
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}
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fn partial_eq_expand(
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db: &dyn AstDatabase,
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id: MacroCallId,
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tt: &tt::Subtree,
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) -> ExpandResult<tt::Subtree> {
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let krate = find_builtin_crate(db, id);
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expand_simple_derive(tt, quote! { #krate::cmp::PartialEq })
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}
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fn ord_expand(
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db: &dyn AstDatabase,
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id: MacroCallId,
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tt: &tt::Subtree,
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) -> ExpandResult<tt::Subtree> {
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let krate = find_builtin_crate(db, id);
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expand_simple_derive(tt, quote! { #krate::cmp::Ord })
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}
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fn partial_ord_expand(
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db: &dyn AstDatabase,
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id: MacroCallId,
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tt: &tt::Subtree,
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) -> ExpandResult<tt::Subtree> {
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let krate = find_builtin_crate(db, id);
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expand_simple_derive(tt, quote! { #krate::cmp::PartialOrd })
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}
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