token_holder.h

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#pragma once
 
#include <cstdint>
 
#include "BashSpark/shell/shell_keyword.h"
#include "BashSpark/shell/shell_tokenizer.h"
 
namespace bs {
    class token_holder {
    public:
        token_holder(
            ifakestream &oIstream,
            std::vector<shell_token> vTokens
        ) : m_oIstream(oIstream),
            m_vTokens(std::move(vTokens)) {
        }
 
        [[nodiscard]] const shell_token *current() const noexcept {
            if (m_nPos >= m_vTokens.size() || m_nPos < 0) return nullptr;
            return &m_vTokens[m_nPos];
        }
 
        [[nodiscard]] const shell_token *next() const noexcept {
            if (m_nPos + 1 >= m_vTokens.size() || m_nPos + 1 < 0) return nullptr;
            return &m_vTokens[m_nPos + 1];
        }
 
        [[nodiscard]] const shell_token *previous() const noexcept {
            if (m_nPos >= m_vTokens.size() + 1 || m_nPos <= 0) return nullptr;
            return &m_vTokens[m_nPos - 1];
        }
 
        const shell_token *get() noexcept {
            ++m_nPos;
            if (m_nPos >= m_vTokens.size()) return nullptr;
            return &m_vTokens[m_nPos];
        }
 
        void put_back() noexcept {
            --m_nPos;
        }
 
        [[nodiscard]] std::size_t pos() const noexcept {
            if (m_nPos >= m_vTokens.size() || m_nPos < 0) return m_oIstream.size();
            return m_nPos;
        }
 
        [[nodiscard]] bool is(const shell_token_type nType) const noexcept {
            if (m_nPos >= m_vTokens.size() || m_nPos < 0) return false;
            return m_vTokens[m_nPos].m_nType == nType;
        }
 
        [[nodiscard]] bool is_next(const shell_token_type nType) const noexcept {
            if (m_nPos + 1 >= m_vTokens.size()) return false;
            return m_vTokens[m_nPos + 1].m_nType == nType;
        }
 
        [[nodiscard]] shell_keyword keyword() const noexcept;
 
        [[nodiscard]] bool keyword(const shell_keyword nKeyword) const noexcept {
            return this->keyword() == nKeyword;
        }
 
    private:
        ifakestream &m_oIstream;
        std::vector<shell_token> m_vTokens;
        std::intptr_t m_nPos = -1;
    };
 
    inline shell_keyword token_holder::keyword() const noexcept {
        // Get current and next
        const auto pCurrent = this->current();
        if (pCurrent == nullptr) return shell_keyword::SK_NONE;
        const auto pNext = this->next();
 
        // Finish if next is null
        if (pNext == nullptr) {
            if (pCurrent->m_nType == shell_token_type::TK_WORD)
                return get_keyword_id(pCurrent->m_sTokenText);
            return shell_keyword::SK_NONE;
        }
 
        // Check next token
        if (
            const auto nTypeNext = pNext->m_nType;
            nTypeNext != shell_token_type::TK_SPACE
            && nTypeNext != shell_token_type::TK_CMD_SEPARATOR
            && nTypeNext != shell_token_type::TK_OPEN_PARENTHESIS
            && nTypeNext != shell_token_type::TK_OPEN_BRACKETS
            && nTypeNext != shell_token_type::TK_OPEN_SQR_BRACKETS
            && nTypeNext != shell_token_type::TK_CLOSE_PARENTHESIS
            && nTypeNext != shell_token_type::TK_CLOSE_BRACKETS
            && nTypeNext != shell_token_type::TK_CLOSE_SQR_BRACKETS
        ) {
            return shell_keyword::SK_NONE;
        }
 
        if (pCurrent->m_nType == shell_token_type::TK_WORD)
            return get_keyword_id(pCurrent->m_sTokenText);
        return shell_keyword::SK_NONE;
    }
}