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/**
* lisp-compiler: Compiles LISP using LLVM.
* Copyright (C) 2022 Clyne Sullivan
*
* This program is free software: you can redistribute it and/or modify it under
* the terms of the GNU General Public License as published by the Free Software
* Foundation, either version 3 of the License, or (at your option) any later
* version.
*
* This program is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
* FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
* details.
*
* You should have received a copy of the GNU General Public License along with
* this program. If not, see <http://www.gnu.org/licenses/>.
*
* @file parser.hpp
* @brief Source code parser to produce AST.
*/
#ifndef PARSER_HPP
#define PARSER_HPP
#include "ast.hpp"
#include <deque>
#include <optional>
#include <string>
#include <variant>
class Parser {
public:
enum Error {
ExpectedProcedureCallOpen,
ExpectedIdentifier,
ExpectedProcedureCallClose,
ExpectedArgumentList,
UnknownIdentifier,
InvalidExpression,
InvalidOperand,
InvalidCondition,
InvalidThenBranch,
InvalidElseBranch,
InvalidInitializer,
InvalidAssignValue,
InvalidArgumentName,
InvalidLambdaBody
};
/**
* Appends the given string to the end of the text queue.
* Call parse() after adding text to produce the AST.
*/
void addString(const std::string&);
/**
* Attempts to parse all text in the text queue, stopping if there is an
* error.
* @return An iterable collection of produced AST nodes.
*/
std::deque<AST::Node *> parse();
std::string describeErrors() noexcept;
bool hasErrors() const noexcept {
return !errors.empty();
}
private:
std::deque<char> text;
std::deque<Error> errors;
/**
* Advances through the text queue until a non-whitespace character is
* found.
*/
void consumeWhitespace() noexcept;
/**
* Attempts to consume an identifier from the text queue.
* @return A string containing the identifier if one is found.
*/
std::optional<std::string> consumeIdentifier() noexcept;
/**
* Attempts to consume a literal number from the text queue.
* @return The number if one is found: an integer if there is no decimal
* point; otherwise, a double.
* TODO Ensure and add noexcept.
*/
std::optional<std::variant<int, double>> consumeLiteralNumber();
AST::Node *parseExpression();
AST::Node *parseProcedureCall();
AST::Node *parseConditional();
AST::Node *parseDefinition();
AST::Node *parseAssignment();
AST::Node *parseLambdaExpression();
};
#endif // PARSER_HPP
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