diff options
Diffstat (limited to 'server')
-rw-r--r-- | server/lexer/token_type.cpp | 1 | ||||
-rw-r--r-- | server/lexer/token_type.hpp | 1 | ||||
-rw-r--r-- | server/parser/operator.hpp | 27 | ||||
-rw-r--r-- | server/parser/parser.hpp | 12 |
4 files changed, 40 insertions, 1 deletions
diff --git a/server/lexer/token_type.cpp b/server/lexer/token_type.cpp index cafb403..6a42a3d 100644 --- a/server/lexer/token_type.cpp +++ b/server/lexer/token_type.cpp @@ -35,6 +35,7 @@ private: {Type::MINUS, "-"}, {Type::ASTERISK, "*"}, {Type::SLASH, "/"}, + {Type::CARET, "^"}, {Type::LEFT_PAREN, "("}, {Type::RIGHT_PAREN, ")"}, {Type::NUMBER, "number"}, diff --git a/server/lexer/token_type.hpp b/server/lexer/token_type.hpp index fba2abb..2040d28 100644 --- a/server/lexer/token_type.hpp +++ b/server/lexer/token_type.hpp @@ -18,6 +18,7 @@ enum class Type { MINUS, ASTERISK, SLASH, + CARET, LEFT_PAREN, RIGHT_PAREN, NUMBER, diff --git a/server/parser/operator.hpp b/server/parser/operator.hpp index f1c24de..86b9eb1 100644 --- a/server/parser/operator.hpp +++ b/server/parser/operator.hpp @@ -10,6 +10,8 @@ #include "../lexer/token.hpp" #include "../lexer/token_type.hpp" +#include <cmath> + namespace math::server::parser { class BinaryOp { @@ -23,6 +25,7 @@ public: case Type::MINUS: case Type::ASTERISK: case Type::SLASH: + case Type::CARET: return true; default: @@ -49,25 +52,49 @@ public: case Type::SLASH: return min_precedence() + 1; + case Type::CARET: + return min_precedence() + 2; + default: throw ParserError{"internal: undefined operator precedence"}; } } + bool is_right_associative() const { + switch (m_type) { + case Type::CARET: + return true; + + default: + return false; + } + } + + bool is_left_associative() const { + return !is_right_associative(); + } + double exec(double lhs, double rhs) const { switch (m_type) { case Type::PLUS: return lhs + rhs; + case Type::MINUS: return lhs - rhs; + case Type::ASTERISK: return lhs * rhs; + case Type::SLASH: // Trapping the CPU would be better? if (rhs == 0.) { throw ParserError{"division by zero"}; } return lhs / rhs; + + case Type::CARET: + return std::pow(lhs, rhs); + default: throw ParserError{"internal: unsupported operator"}; } diff --git a/server/parser/parser.hpp b/server/parser/parser.hpp index ac87fbe..596f84f 100644 --- a/server/parser/parser.hpp +++ b/server/parser/parser.hpp @@ -45,7 +45,17 @@ private: m_lexer.drop_token(); auto rhs = exec_primary(); - for (op = peek_operator(); op.has_value() && op->get_precedence() > lhs_op.get_precedence(); op = peek_operator()) { + for (op = peek_operator(); op.has_value(); op = peek_operator()) { + const auto op_prec = op->get_precedence(); + const auto lhs_prec = lhs_op.get_precedence(); + const auto ok_left_assoc = op->is_left_associative() && op_prec > lhs_prec; + const auto ok_right_assoc = op->is_right_associative() && op_prec == lhs_prec; + const auto ok = ok_left_assoc || ok_right_assoc; + + if (!ok) { + break; + } + rhs = exec_expr(rhs, op->get_precedence()); } |