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Refactor Pattern and FunctionParameter handling for Parser consistency (#2385)

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While the Parser has similar divergent states, lists of Expressions tend to be handled more like this. I'm keeping the divergent start state in order to continue support of a distinct error, but I think this organization of FunctionParameter/FunctionParameterFinish will be less surprising.
This commit is contained in:
Jon Ross-Perkins
2022-11-15 22:36:52 -08:00
committed by GitHub
parent dfbe35bae5
commit 310cf0d2f9
3 changed files with 60 additions and 69 deletions
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toolchain/parser/parser.cpp
+33 -36
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@@ -1004,6 +1004,27 @@ auto Parser::HandleFunctionIntroducerState() -> void {
// Advance past the open paren.
++position_;
if (!PositionIs(TokenKind::CloseParen())) {
PushState(ParserState::FunctionParameter());
}
}
auto Parser::HandleFunctionParameterState() -> void {
PopAndDiscardState();
PushState(ParserState::FunctionParameterFinish());
PushState(ParserState::PatternAsFunctionParameter());
}
auto Parser::HandleFunctionParameterFinishState() -> void {
auto state = PopState();
if (state.has_error) {
ReturnErrorOnState();
}
if (ConsumeListToken(ParseNodeKind::ParameterListComma(),
TokenKind::CloseParen(),
state.has_error) == ListTokenKind::Comma) {
PushState(ParserState::PatternAsFunctionParameter());
}
}
@@ -1270,20 +1291,11 @@ auto Parser::HandleParenExpressionFinishAsTupleState() -> void {
state.has_error);
}
auto Parser::HandlePatternStart(PatternKind pattern_kind) -> void {
auto Parser::HandlePattern(PatternKind pattern_kind) -> void {
auto state = PopState();
// Ensure the finish state always follows.
switch (pattern_kind) {
case PatternKind::Parameter: {
state.state = ParserState::PatternAsFunctionParameterFinish();
break;
}
case PatternKind::Variable: {
state.state = ParserState::PatternAsVariableFinish();
break;
}
}
state.state = ParserState::PatternFinish();
// Handle an invalid pattern introducer.
if (!PositionIs(TokenKind::Identifier()) ||
@@ -1316,41 +1328,26 @@ auto Parser::HandlePatternStart(PatternKind pattern_kind) -> void {
position_ += 2;
}
auto Parser::HandlePatternFinish() -> bool {
auto Parser::HandlePatternAsFunctionParameterState() -> void {
HandlePattern(PatternKind::Parameter);
}
auto Parser::HandlePatternAsVariableState() -> void {
HandlePattern(PatternKind::Variable);
}
auto Parser::HandlePatternFinishState() -> void {
auto state = PopState();
// If an error was encountered, propagate it without adding a node.
if (state.has_error) {
ReturnErrorOnState();
return true;
return;
}
// TODO: may need to mark has_error if !type.
AddNode(ParseNodeKind::PatternBinding(), state.token, state.subtree_start,
/*has_error=*/false);
return false;
}
auto Parser::HandlePatternAsFunctionParameterState() -> void {
HandlePatternStart(PatternKind::Parameter);
}
auto Parser::HandlePatternAsFunctionParameterFinishState() -> void {
bool has_error = HandlePatternFinish();
if (ConsumeListToken(ParseNodeKind::ParameterListComma(),
TokenKind::CloseParen(),
has_error) == ListTokenKind::Comma) {
PushState(ParserState::PatternAsFunctionParameter());
}
}
auto Parser::HandlePatternAsVariableState() -> void {
HandlePatternStart(PatternKind::Variable);
}
auto Parser::HandlePatternAsVariableFinishState() -> void {
HandlePatternFinish();
}
auto Parser::HandleStatementState() -> void {