Niels Lohmann
ffd4242dc2
* Docs: fill documentation gaps found in user questions Add pages on class-hierarchy/smart-pointer/variant/chrono recipes, working without exceptions, and large, streamed and partial input. Extend the FAQ (23 entries, Known bugs first), parse error documentation (empty-input checklist, line/column, diagnostic positions), element access, conversions, creating values, ADL troubleshooting, memory, and build/distribution notes. Add 14 examples with generated output. Correct the statement that parse errors cannot be recovered from with -fno-exceptions. The topics come from recurring questions on Stack Overflow, Reddit, Hacker News, YouTube, and the project's GitHub discussions and issues. Signed-off-by: Niels Lohmann <mail@nlohmann.me> * docs: declare range-for lists in variables to keep astyle quiet astyle reformats a braced init list placed directly in a range-for header; declare the list first so check_amalgamation passes. Signed-off-by: Niels Lohmann <mail@nlohmann.me> --------- Signed-off-by: Niels Lohmann <mail@nlohmann.me>
43 lines
1007 B
C++
43 lines
1007 B
C++
#include <iostream>
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#include <utility>
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#include <nlohmann/json.hpp>
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using json = nlohmann::json;
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// line and column (both starting at 1) of a byte index in a text
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std::pair<std::size_t, std::size_t> line_column(const std::string& input, std::size_t byte)
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{
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std::size_t line = 1;
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std::size_t column = 1;
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for (std::size_t i = 0; i + 1 < byte && i < input.size(); ++i)
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{
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if (input[i] == '\n')
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{
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++line;
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column = 1;
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}
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else
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{
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++column;
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}
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}
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return {line, column};
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}
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int main()
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{
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const std::string input = "{\n \"a\": 1,\n \"b\": ]\n}";
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try
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{
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const json j = json::parse(input);
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std::cout << j << '\n';
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}
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catch (const json::parse_error& e)
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{
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const auto position = line_column(input, e.byte);
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std::cout << e.what() << '\n';
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std::cout << "byte " << e.byte << " = line " << position.first << ", column " << position.second << '\n';
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}
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}
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