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Lex/parse support for ->?, :?, and form literals (#6695)

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See #5389 (pending) for the language design.
This commit is contained in:
Geoff Romer
2026-02-07 02:41:22 +00:00
committed by GitHub
parent 1382a8645a
commit 7938d9a8d0
31 changed files with 758 additions and 195 deletions
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toolchain/parse/handle_binding_pattern.cpp
+41 -16
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@@ -14,9 +14,10 @@ auto HandleBindingPattern(Context& context) -> void {
// Handle an invalid pattern introducer for parameters and variables.
auto on_error = [&](bool expected_name) {
if (!state.has_error) {
CARBON_DIAGNOSTIC(ExpectedBindingPattern, Error,
"expected {0:name|`:` or `:!`} in binding pattern",
Diagnostics::BoolAsSelect);
CARBON_DIAGNOSTIC(
ExpectedBindingPattern, Error,
"expected {0:name|`:`, `:!`, or `:?`} in binding pattern",
Diagnostics::BoolAsSelect);
context.emitter().Emit(*context.position(), ExpectedBindingPattern,
expected_name);
state.has_error = true;
@@ -51,7 +52,8 @@ auto HandleBindingPattern(Context& context) -> void {
if (auto token_kind = context.PositionKind();
token_kind == Lex::TokenKind::Colon ||
token_kind == Lex::TokenKind::ColonExclaim) {
token_kind == Lex::TokenKind::ColonExclaim ||
token_kind == Lex::TokenKind::ColonQuestion) {
// Add the wrapper node for the `template` keyword if present.
if (template_token) {
if (token_kind != Lex::TokenKind::ColonExclaim && !state.has_error) {
@@ -75,10 +77,21 @@ auto HandleBindingPattern(Context& context) -> void {
context.AddNode(NodeKind::RefBindingName, *ref_token, state.has_error);
}
state.kind = token_kind == Lex::TokenKind::Colon
? StateKind::BindingPatternFinishAsRegular
: StateKind::BindingPatternFinishAsGeneric;
// Use the `:` or `:!` for the root node.
switch (token_kind) {
case Lex::TokenKind::Colon:
state.kind = StateKind::BindingPatternFinishAsRegular;
break;
case Lex::TokenKind::ColonExclaim:
state.kind = StateKind::BindingPatternFinishAsGeneric;
break;
case Lex::TokenKind::ColonQuestion:
state.kind = StateKind::BindingPatternFinishAsForm;
break;
default:
CARBON_FATAL("Unexpected token kind");
}
// Use the `:`, `:!`, or `:?` for the root node.
state.token = context.Consume();
if (token_kind == Lex::TokenKind::ColonExclaim) {
@@ -99,24 +112,32 @@ auto HandleBindingPattern(Context& context) -> void {
}
// Handles BindingPatternFinishAs(Generic|Regular).
static auto HandleBindingPatternFinish(Context& context, bool is_compile_time)
static auto HandleBindingPatternFinish(Context& context, StateKind finish_kind)
-> void {
auto state = context.PopState();
auto node_kind = NodeKind::InvalidParse;
if (state.in_var_pattern) {
node_kind = NodeKind::VarBindingPattern;
if (is_compile_time) {
if (finish_kind == StateKind::BindingPatternFinishAsGeneric) {
CARBON_DIAGNOSTIC(CompileTimeBindingInVarDecl, Error,
"`var` pattern cannot declare a compile-time binding");
context.emitter().Emit(*context.position(), CompileTimeBindingInVarDecl);
state.has_error = true;
}
} else {
if (is_compile_time) {
node_kind = NodeKind::CompileTimeBindingPattern;
} else {
node_kind = NodeKind::LetBindingPattern;
switch (finish_kind) {
case StateKind::BindingPatternFinishAsGeneric:
node_kind = NodeKind::CompileTimeBindingPattern;
break;
case StateKind::BindingPatternFinishAsRegular:
node_kind = NodeKind::LetBindingPattern;
break;
case StateKind::BindingPatternFinishAsForm:
node_kind = NodeKind::FormBindingPattern;
break;
default:
CARBON_FATAL("Unexpected StateKind {0}", finish_kind);
}
}
context.AddNode(node_kind, state.token, state.has_error);
@@ -129,11 +150,15 @@ static auto HandleBindingPatternFinish(Context& context, bool is_compile_time)
}
auto HandleBindingPatternFinishAsGeneric(Context& context) -> void {
HandleBindingPatternFinish(context, /*is_compile_time=*/true);
HandleBindingPatternFinish(context, StateKind::BindingPatternFinishAsGeneric);
}
auto HandleBindingPatternFinishAsRegular(Context& context) -> void {
HandleBindingPatternFinish(context, /*is_compile_time=*/false);
HandleBindingPatternFinish(context, StateKind::BindingPatternFinishAsRegular);
}
auto HandleBindingPatternFinishAsForm(Context& context) -> void {
HandleBindingPatternFinish(context, StateKind::BindingPatternFinishAsForm);
}
} // namespace Carbon::Parse