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Better parsing of if then else

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This commit is contained in:
Rafał Grodziński
2025-06-13 11:13:13 +09:00
parent 37bcb5c2c7
commit 6b67154260
4 changed files with 32 additions and 33 deletions
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57
src/Parser.cpp
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@@ -45,7 +45,6 @@ shared_ptr<Statement> Parser::nextStatement() {
}
shared_ptr<Statement> Parser::matchStatementFunctionDeclaration() {
//if (!matchesTokenKinds({TokenKind::IDENTIFIER, TokenKind::COLON, TokenKind::FUNCTION}))
if (!tryMatchingTokenKinds({TokenKind::IDENTIFIER, TokenKind::COLON, TokenKind::FUNCTION}, true, false))
return nullptr;
@@ -59,13 +58,16 @@ shared_ptr<Statement> Parser::matchStatementFunctionDeclaration() {
currentIndex++;
currentIndex++; // new line
shared_ptr<Statement> statementBlock = matchStatementBlock();
shared_ptr<Statement> statementBlock = matchStatementBlock({TokenKind::SEMICOLON}, true);
if (statementBlock == nullptr)
return matchStatementInvalid();
else if (!statementBlock->isValid())
return statementBlock;
else
return make_shared<StatementFunctionDeclaration>(identifierToken->getLexme(), ValueType::SINT32, dynamic_pointer_cast<StatementBlock>(statementBlock));
if(!tryMatchingTokenKinds({TokenKind::NEW_LINE}, false, true))
return matchStatementInvalid("Expected a new line after a function declaration");
return make_shared<StatementFunctionDeclaration>(identifierToken->getLexme(), ValueType::SINT32, dynamic_pointer_cast<StatementBlock>(statementBlock));
}
shared_ptr<Statement> Parser::matchStatementVarDeclaration() {
@@ -99,16 +101,17 @@ shared_ptr<Statement> Parser::matchStatementVarDeclaration() {
return matchStatementInvalid();
// Expect new line
if (!tryMatchingTokenKinds({TokenKind::NEW_LINE}, true, true))
return matchStatementInvalid("Expected a new line");
if (!tryMatchingTokenKinds({TokenKind::NEW_LINE}, false, true))
return matchStatementInvalid("Expected a new line after variable declaration");
return make_shared<StatementVarDeclaration>(identifierToken->getLexme(), valueType, expression);
}
shared_ptr<Statement> Parser::matchStatementBlock() {
shared_ptr<Statement> Parser::matchStatementBlock(vector<TokenKind> terminalTokenKinds, bool shouldConsumeTerminal) {
vector<shared_ptr<Statement>> statements;
while (!tryMatchingTokenKinds({TokenKind::SEMICOLON, TokenKind::COLON}, false, false)) {
bool hasNewLineTerminal = find(terminalTokenKinds.begin(), terminalTokenKinds.end(), TokenKind::NEW_LINE) != terminalTokenKinds.end();
while (!tryMatchingTokenKinds(terminalTokenKinds, false, shouldConsumeTerminal)) {
shared_ptr<Statement> statement = nextStatement();
if (statement == nullptr)
return matchStatementInvalid();
@@ -116,15 +119,12 @@ shared_ptr<Statement> Parser::matchStatementBlock() {
return statement;
else
statements.push_back(statement);
}
// consune ';' only
if (tryMatchingTokenKinds({TokenKind::SEMICOLON}, true, true)) {
if (!tryMatchingTokenKinds({TokenKind::NEW_LINE, TokenKind::END}, false, false))
return matchStatementInvalid();
tryMatchingTokenKinds({TokenKind::NEW_LINE}, true, true);
if (hasNewLineTerminal && tokens.at(currentIndex-1)->getKind() == TokenKind::NEW_LINE)
currentIndex--;
}
return make_shared<StatementBlock>(statements);
}
@@ -302,7 +302,6 @@ shared_ptr<Expression> Parser::matchExpressionIfElse() {
// Try maching '?'
shared_ptr<Token> token = tokens.at(currentIndex);
//if (!tryAdvancingForOneOfTokenKinds({TokenKind::QUESTION}))
if (!tryMatchingTokenKinds({TokenKind::QUESTION}, true, true))
return nullptr;
@@ -313,37 +312,33 @@ shared_ptr<Expression> Parser::matchExpressionIfElse() {
else if (!condition->isValid())
return condition;
// Match ':', '\n', or ':\n'
if (tryMatchingTokenKinds({TokenKind::COLON, TokenKind::NEW_LINE}, true, false))
currentIndex += 2;
else if (tryMatchingTokenKinds({TokenKind::COLON, TokenKind::NEW_LINE}, false, false))
currentIndex++;
else
return matchExpressionInvalid();
// Consume optional ':'
tryMatchingTokenKinds({TokenKind::COLON}, true, true);
// Consume optional new line
tryMatchingTokenKinds({TokenKind::NEW_LINE}, true, true);
// Match then block
shared_ptr<Statement> thenBlock = matchStatementBlock();
shared_ptr<Statement> thenBlock = matchStatementBlock({TokenKind::COLON, TokenKind::SEMICOLON}, false);
if (thenBlock == nullptr)
return matchExpressionInvalid();
else if (!thenBlock->isValid())
return matchExpressionInvalid(); // FIXME
// Match else block
// Match else block. Then and else block are separated by ':'
shared_ptr<Statement> elseBlock;
if (tryMatchingTokenKinds({TokenKind::COLON}, true, true)) {
tryMatchingTokenKinds({TokenKind::NEW_LINE}, true, true);
bool isSingleLine = !tryMatchingTokenKinds({TokenKind::NEW_LINE}, true, true);
vector<TokenKind> terminalTokens = {TokenKind::SEMICOLON};
if (isSingleLine)
terminalTokens.push_back(TokenKind::NEW_LINE);
elseBlock = matchStatementBlock();
elseBlock = matchStatementBlock(terminalTokens, false);
if (elseBlock == nullptr)
return matchExpressionInvalid();
else if (!elseBlock->isValid())
return matchExpressionInvalid(); // FIXME
// hack to treat statement as an expression
if (tokens.at(currentIndex-1)->getKind() == TokenKind::NEW_LINE)
currentIndex--;
}
tryMatchingTokenKinds({TokenKind::SEMICOLON}, true, true);
return make_shared<ExpressionIfElse>(condition, dynamic_pointer_cast<StatementBlock>(thenBlock), dynamic_pointer_cast<StatementBlock>(elseBlock));
}