Rename ParamList to TuplePattern (#3479)

Co-authored-by: Richard Smith <richard@metafoo.co.uk>

toolchain/parse/handle_pattern_list.cpp

@@ -0,0 +1,103 @@
+// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
+// Exceptions. See /LICENSE for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+#include "toolchain/parse/context.h"
+
+namespace Carbon::Parse {
+
+// Handles PatternListElementAs(Implicit|Tuple).
+static auto HandlePatternListElement(Context& context, State pattern_state,
+                                     State finish_state) -> void {
+  context.PopAndDiscardState();
+
+  context.PushState(finish_state);
+  context.PushState(pattern_state);
+}
+
+auto HandlePatternListElementAsImplicit(Context& context) -> void {
+  HandlePatternListElement(context, State::BindingPattern,
+                           State::PatternListElementFinishAsImplicit);
+}
+
+auto HandlePatternListElementAsTuple(Context& context) -> void {
+  HandlePatternListElement(context, State::BindingPattern,
+                           State::PatternListElementFinishAsTuple);
+}
+
+// Handles PatternListElementFinishAs(Implicit|Tuple).
+static auto HandlePatternListElementFinish(Context& context,
+                                           Lex::TokenKind close_token,
+                                           State param_state) -> void {
+  auto state = context.PopState();
+
+  if (state.has_error) {
+    context.ReturnErrorOnState();
+  }
+
+  if (context.ConsumeListToken(NodeKind::PatternListComma, close_token,
+                               state.has_error) ==
+      Context::ListTokenKind::Comma) {
+    context.PushState(param_state);
+  }
+}
+
+auto HandlePatternListElementFinishAsImplicit(Context& context) -> void {
+  HandlePatternListElementFinish(context, Lex::TokenKind::CloseSquareBracket,
+                                 State::PatternListElementAsImplicit);
+}
+
+auto HandlePatternListElementFinishAsTuple(Context& context) -> void {
+  HandlePatternListElementFinish(context, Lex::TokenKind::CloseParen,
+                                 State::PatternListElementAsTuple);
+}
+
+// Handles PatternListAs(Implicit|Tuple).
+static auto HandlePatternList(Context& context, NodeKind parse_node_kind,
+                              Lex::TokenKind open_token_kind,
+                              Lex::TokenKind close_token_kind,
+                              State param_state, State finish_state) -> void {
+  context.PopAndDiscardState();
+
+  context.PushState(finish_state);
+  context.AddLeafNode(parse_node_kind, context.ConsumeChecked(open_token_kind));
+
+  if (!context.PositionIs(close_token_kind)) {
+    context.PushState(param_state);
+  }
+}
+
+auto HandlePatternListAsImplicit(Context& context) -> void {
+  HandlePatternList(
+      context, NodeKind::ImplicitParamListStart,
+      Lex::TokenKind::OpenSquareBracket, Lex::TokenKind::CloseSquareBracket,
+      State::PatternListElementAsImplicit, State::PatternListFinishAsImplicit);
+}
+
+auto HandlePatternListAsTuple(Context& context) -> void {
+  HandlePatternList(context, NodeKind::TuplePatternStart,
+                    Lex::TokenKind::OpenParen, Lex::TokenKind::CloseParen,
+                    State::PatternListElementAsTuple,
+                    State::PatternListFinishAsTuple);
+}
+
+// Handles PatternListFinishAs(Implicit|Tuple).
+static auto HandlePatternListFinish(Context& context, NodeKind parse_node_kind,
+                                    Lex::TokenKind token_kind) -> void {
+  auto state = context.PopState();
+
+  context.AddNode(parse_node_kind, context.ConsumeChecked(token_kind),
+                  state.subtree_start, state.has_error);
+}
+
+auto HandlePatternListFinishAsImplicit(Context& context) -> void {
+  HandlePatternListFinish(context, NodeKind::ImplicitParamList,
+                          Lex::TokenKind::CloseSquareBracket);
+}
+
+auto HandlePatternListFinishAsTuple(Context& context) -> void {
+  HandlePatternListFinish(context, NodeKind::TuplePattern,
+                          Lex::TokenKind::CloseParen);
+}
+
+}  // namespace Carbon::Parse