diff options
Diffstat (limited to 'server')
| -rw-r--r-- | server/parser/parser.hpp | 24 |
1 files changed, 18 insertions, 6 deletions
diff --git a/server/parser/parser.hpp b/server/parser/parser.hpp index 7d6f31d..fb2a5ff 100644 --- a/server/parser/parser.hpp +++ b/server/parser/parser.hpp @@ -36,7 +36,7 @@ public: private: double exec_expr() { - return exec_expr(exec_primary(), parser::BinaryOp::min_precedence()); + return exec_expr(exec_factor(), parser::BinaryOp::min_precedence()); } double exec_expr(double lhs, unsigned min_prec) { @@ -45,7 +45,7 @@ private: const auto prev_prec = prev.get_precedence(); m_lexer.drop_token(); - auto rhs = exec_primary(); + auto rhs = exec_factor(); for (op = peek_operator(); op.has_value(); op = peek_operator()) { const auto next = *op; @@ -77,16 +77,28 @@ private: return parser::BinaryOp::from_token(*token); } - double exec_primary() { + double exec_factor() { if (!m_lexer.has_token()) { - throw ParserError{"expected '-', '(' or a number"}; + throw ParserError{"expected '-', '+', '(' or a number"}; } using Type = lexer::Token::Type; if (m_lexer.drop_token_of_type(Type::MINUS).has_value()) { - return -exec_primary(); + return -exec_factor(); } + if (m_lexer.drop_token_of_type(Type::PLUS).has_value()) { + return exec_factor(); + } + return exec_atom(); + } + + double exec_atom() { + if (!m_lexer.has_token()) { + throw ParserError{"expected '-', '+', '(' or a number"}; + } + + using Type = lexer::Token::Type; if (m_lexer.drop_token_of_type(Type::LEFT_PAREN).has_value()) { const auto inner = exec_expr(); @@ -100,7 +112,7 @@ private: return token.value().as_number(); } - throw ParserError{"expected '-', '(' or a number"}; + throw ParserError{"expected '-', '+', '(' or a number"}; } Lexer m_lexer; |