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authorArthur Cohen <arthur.cohen@embecosm.com>2022-03-14 17:08:07 +0100
committerArthur Cohen <arthur.cohen@embecosm.com>2022-03-17 15:51:06 +0100
commit1a2ef9cae90db5bdb18723b6adafe2750a95ed76 (patch)
treec634ec46956c01a631ba528854975b45b82739a7 /gcc/rust/expand/rust-macro-expand.cc
parent1a14348afefc62313e38156fde768744378f9ebf (diff)
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macros: Add remaining context and improve parsing macro dispatch
This allows us to expand macor invocations in more places, as macro calls are not limited to statements or expressions. It is quite common to use macros to abstract writing repetitive boilerplate for type implementations, for example.
Diffstat (limited to 'gcc/rust/expand/rust-macro-expand.cc')
-rw-r--r--gcc/rust/expand/rust-macro-expand.cc139
1 files changed, 104 insertions, 35 deletions
diff --git a/gcc/rust/expand/rust-macro-expand.cc b/gcc/rust/expand/rust-macro-expand.cc
index 3389f20..80f822b 100644
--- a/gcc/rust/expand/rust-macro-expand.cc
+++ b/gcc/rust/expand/rust-macro-expand.cc
@@ -786,7 +786,6 @@ parse_many (Parser<MacroInvocLexer> &parser, TokenId &delimiter,
std::function<AST::SingleASTNode ()> parse_fn)
{
std::vector<AST::SingleASTNode> nodes;
-
while (true)
{
if (parser.peek_current_token ()->get_id () == delimiter)
@@ -815,6 +814,52 @@ transcribe_many_items (Parser<MacroInvocLexer> &parser, TokenId &delimiter)
}
/**
+ * Transcribe 0 or more external items from a macro invocation
+ *
+ * @param parser Parser to extract items from
+ * @param delimiter Id of the token on which parsing should stop
+ */
+static std::vector<AST::SingleASTNode>
+transcribe_many_ext (Parser<MacroInvocLexer> &parser, TokenId &delimiter)
+{
+ return parse_many (parser, delimiter, [&parser] () {
+ auto item = parser.parse_external_item ();
+ return AST::SingleASTNode (std::move (item));
+ });
+}
+
+/**
+ * Transcribe 0 or more trait items from a macro invocation
+ *
+ * @param parser Parser to extract items from
+ * @param delimiter Id of the token on which parsing should stop
+ */
+static std::vector<AST::SingleASTNode>
+transcribe_many_trait_items (Parser<MacroInvocLexer> &parser,
+ TokenId &delimiter)
+{
+ return parse_many (parser, delimiter, [&parser] () {
+ auto item = parser.parse_trait_item ();
+ return AST::SingleASTNode (std::move (item));
+ });
+}
+
+/**
+ * Transcribe 0 or more impl items from a macro invocation
+ *
+ * @param parser Parser to extract items from
+ * @param delimiter Id of the token on which parsing should stop
+ */
+static std::vector<AST::SingleASTNode>
+transcribe_many_impl_items (Parser<MacroInvocLexer> &parser, TokenId &delimiter)
+{
+ return parse_many (parser, delimiter, [&parser] () {
+ auto item = parser.parse_inherent_impl_item ();
+ return AST::SingleASTNode (std::move (item));
+ });
+}
+
+/**
* Transcribe 0 or more statements from a macro invocation
*
* @param parser Parser to extract statements from
@@ -845,6 +890,57 @@ transcribe_expression (Parser<MacroInvocLexer> &parser)
return {AST::SingleASTNode (std::move (expr))};
}
+static std::vector<AST::SingleASTNode>
+transcribe_on_delimiter (Parser<MacroInvocLexer> &parser, bool semicolon,
+ AST::DelimType delimiter, TokenId last_token_id)
+{
+ if (semicolon || delimiter == AST::DelimType::CURLY)
+ return transcribe_many_stmts (parser, last_token_id);
+ else
+ return transcribe_expression (parser);
+} // namespace Rust
+
+static std::vector<AST::SingleASTNode>
+transcribe_context (MacroExpander::ContextType ctx,
+ Parser<MacroInvocLexer> &parser, bool semicolon,
+ AST::DelimType delimiter, TokenId last_token_id)
+{
+ // The flow-chart in order to choose a parsing function is as follows:
+ //
+ // [switch special context]
+ // -- Item --> parser.parse_item();
+ // -- Trait --> parser.parse_trait_item();
+ // -- Impl --> parser.parse_impl_item();
+ // -- Extern --> parser.parse_extern_item();
+ // -- None --> [has semicolon?]
+ // -- Yes --> parser.parse_stmt();
+ // -- No --> [switch invocation.delimiter()]
+ // -- { } --> parser.parse_stmt();
+ // -- _ --> parser.parse_expr(); // once!
+
+ // If there is a semicolon OR we are expanding a MacroInvocationSemi, then
+ // we can parse multiple items. Otherwise, parse *one* expression
+
+ switch (ctx)
+ {
+ case MacroExpander::ContextType::ITEM:
+ return transcribe_many_items (parser, last_token_id);
+ break;
+ case MacroExpander::ContextType::TRAIT:
+ return transcribe_many_trait_items (parser, last_token_id);
+ break;
+ case MacroExpander::ContextType::IMPL:
+ return transcribe_many_impl_items (parser, last_token_id);
+ break;
+ case MacroExpander::ContextType::EXTERN:
+ return transcribe_many_ext (parser, last_token_id);
+ break;
+ default:
+ return transcribe_on_delimiter (parser, semicolon, delimiter,
+ last_token_id);
+ }
+}
+
AST::ASTFragment
MacroExpander::transcribe_rule (
AST::MacroRule &match_rule, AST::DelimTokenTree &invoc_token_tree,
@@ -864,18 +960,15 @@ MacroExpander::transcribe_rule (
std::vector<std::unique_ptr<AST::Token>> substituted_tokens
= substitute_context.substitute_tokens ();
+ // handy for debugging
+ // for (auto &tok : substituted_tokens)
+ // rust_debug ("[tok] %s", tok->as_string ().c_str ());
+
// parse it to an ASTFragment
MacroInvocLexer lex (std::move (substituted_tokens));
Parser<MacroInvocLexer> parser (std::move (lex));
- // handy for debugging
- // for (auto &tok : substituted_tokens)
- // {
- // rust_debug ("tok: [%s]", tok->as_string ().c_str ());
- // }
-
auto last_token_id = TokenId::RIGHT_CURLY;
- std::vector<AST::SingleASTNode> nodes;
// this is used so we can check that we delimit the stream correctly.
switch (transcribe_tree.get_delim_type ())
@@ -905,33 +998,9 @@ MacroExpander::transcribe_rule (
// as a statement (either via ExpressionStatement or
// MacroInvocationWithSemi)
- // The flow-chart in order to choose a parsing function is as follows:
- //
- // [is in item context?]
- // -- Yes --> parser.parse_item();
- // -- No --> [has semicolon?]
- // -- Yes --> parser.parse_stmt();
- // -- No --> [switch invocation.delimiter()]
- // -- { } --> parser.parse_stmt();
- // -- _ --> parser.parse_expr();
-
- // If there is a semicolon OR we are expanding a MacroInvocationSemi, then
- // we can parse multiple items. Otherwise, parse *one* expression
-
- if (ctx == ContextType::ITEM)
- nodes = transcribe_many_items (parser, last_token_id);
- else if (semicolon)
- nodes = transcribe_many_stmts (parser, last_token_id);
- else
- switch (invoc_token_tree.get_delim_type ())
- {
- case AST::CURLY:
- nodes = transcribe_many_stmts (parser, last_token_id);
- break;
- default:
- nodes = transcribe_expression (parser);
- break;
- }
+ auto nodes
+ = transcribe_context (ctx, parser, semicolon,
+ invoc_token_tree.get_delim_type (), last_token_id);
// emit any errors
if (parser.has_errors ())