ASTLowerer.hpp

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/**
 * @file ASTLowerver.hpp
 * @author Alexandre Plateau (lexplt.dev@gmail.com)
 * @brief ArkScript compiler is in charge of transforming the AST into IR
 * @date 2020-10-27
 *
 * @copyright Copyright (c) 2020-2025
 *
 */
 
#ifndef ARK_COMPILER_LOWERER_ASTLOWERER_HPP
#define ARK_COMPILER_LOWERER_ASTLOWERER_HPP
 
#include <stack>
#include <vector>
#include <string>
#include <cinttypes>
#include <optional>
 
#include <Ark/Platform.hpp>
#include <Ark/Logger.hpp>
#include <Ark/Compiler/Instructions.hpp>
#include <Ark/Compiler/IntermediateRepresentation/Entity.hpp>
#include <Ark/Compiler/AST/Node.hpp>
#include <Ark/Compiler/ValTableElem.hpp>
#include <Ark/Compiler/Lowerer/LocalsLocator.hpp>
 
namespace Ark::internal
{
    class State;
    class Welder;
 
    /**
     * @brief The ArkScript AST to IR compiler
     *
     */
    class ARK_API ASTLowerer final
    {
    public:
        /**
         * @brief Construct a new ASTLowerer object
         *
         * @param debug the debug level
         */
        explicit ASTLowerer(unsigned debug);
 
        /**
         * @brief Start the compilation
         *
         * @param ast
         */
        void process(Node& ast);
 
        /**
         * @brief Return the IR blocks (one per scope)
         *
         * @return const std::vector<Block>&
         */
        [[nodiscard]] const std::vector<IR::Block>& intermediateRepresentation() const noexcept;
 
        /**
         * @brief Return the symbol table pre-computed
         *
         * @return const std::vector<std::string>&
         */
        [[nodiscard]] const std::vector<std::string>& symbols() const noexcept;
 
        /**
         * @brief Return the value table pre-computed
         *
         * @return const std::vector<ValTableElem>&
         */
        [[nodiscard]] const std::vector<ValTableElem>& values() const noexcept;
 
    private:
        struct Page
        {
            std::size_t index;
            bool is_temp;
        };
 
        LocalsLocator m_locals_locator;
 
        // tables: symbols, values, plugins and codes
        std::vector<std::string> m_symbols;
        std::vector<ValTableElem> m_values;
        std::vector<IR::Block> m_code_pages;
        std::vector<IR::Block> m_temp_pages;  ///< we need temporary code pages for some compilations passes
        IR::label_t m_current_label = 0;
        std::stack<std::string> m_opened_vars;  ///< stack of vars we are currently declaring
 
        Logger m_logger;
 
        /**
         * @brief helper functions to get a temp or finalized code page
         *
         * @param page page descriptor
         * @return std::vector<IR::Block>&
         */
        IR::Block& page(const Page page) noexcept
        {
            if (!page.is_temp)
                return m_code_pages[page.index];
            return m_temp_pages[page.index];
        }
 
        /**
         * @brief Checking if a symbol is an operator
         *
         * @param name symbol name
         * @return std::optional<Instruction> operator instruction
         */
        static std::optional<Instruction> getOperator(const std::string& name) noexcept;
 
        /**
         * @brief Checking if a symbol is a builtin
         *
         * @param name symbol name
         * @return std::optional<uint16_t> builtin number
         */
        static std::optional<uint16_t> getBuiltin(const std::string& name) noexcept;
 
        /**
         * @brief Checking if a symbol is a list instruction
         *
         * @param name
         * @return std::optional<Instruction> list instruction
         */
        static std::optional<Instruction> getListInstruction(const std::string& name) noexcept;
 
        /**
         * Checks if a node is a list and has a keyboard as its first node, indicating if it's producing a value on the stack or not
         * @param node node to check
         * @return true if the node produces an output on the stack (fun, if, begin)
         * @return false otherwise (let, mut, set, while, import, del)
         */
        static bool nodeProducesOutput(const Node& node);
 
        /**
         * @brief Check if a given instruction is unary (takes only one argument)
         *
         * @param inst
         * @return true the instruction is unary
         * @return false
         */
        static bool isUnaryInst(Instruction inst) noexcept;
 
        /**
         * @brief Check if a given instruction is ternary (takes three arguments)
         *
         * @param inst
         * @return true the instruction is ternary
         * @return false
         */
        static bool isTernaryInst(Instruction inst) noexcept;
 
        /**
         * @brief Display a warning message
         *
         * @param message
         * @param node
         */
        static void warning(const std::string& message, const Node& node);
 
        /**
         * @brief Throw a nice error message
         *
         * @param message
         * @param node
         */
        [[noreturn]] static void buildAndThrowError(const std::string& message, const Node& node);
 
        /**
         * @brief Compile an expression (a node) recursively
         *
         * @param x the Node to compile
         * @param p the current page number we're on
         * @param is_result_unused
         * @param is_terminal
         */
        void compileExpression(Node& x, Page p, bool is_result_unused, bool is_terminal);
 
        void compileSymbol(Node& x, Page p, bool is_result_unused);
        void compileListInstruction(Node& x, Page p, bool is_result_unused);
        void compileIf(Node& x, Page p, bool is_result_unused, bool is_terminal);
        void compileFunction(Node& x, Page p, bool is_result_unused);
        void compileLetMutSet(Keyword n, Node& x, Page p);
        void compileWhile(Node& x, Page p);
        void compilePluginImport(Node& x, Page p);
        void pushFunctionCallArguments(Node& call, Page p, bool is_tail_call);
        void handleCalls(Node& x, Page p, bool is_result_unused, bool is_terminal);
 
        /**
         * @brief Register a given node in the symbol table
         * @details Can throw if the table is full
         *
         * @param sym
         * @return uint16_t
         */
        uint16_t addSymbol(const Node& sym);
 
        /**
         * @brief Register a given node in the value table
         * @details Can throw if the table is full
         *
         * @param x
         * @return uint16_t
         */
        uint16_t addValue(const Node& x);
 
        /**
         * @brief Register a page id (function reference) in the value table
         * @details Can throw if the table is full
         *
         * @param page_id
         * @param current A reference to the current node, for context
         * @return std::size_t
         */
        uint16_t addValue(std::size_t page_id, const Node& current);
    };
}
 
#endif