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#pragma once
///@file
#include "lix/libutil/error.hh"
#include <compare>
#include <memory>
#include <optional>
#include <sstream>
#include <string>
#include <variant>
#include <vector>
namespace nix {
namespace cli_literate_parser {
// ------------------------- NODES -------------------------
//
// To update golden test files while preserving commentary output and other `@`
// directives, we need to keep commentary output around after parsing.
struct BaseNode {
virtual ~BaseNode() = default;
virtual auto shouldCompare() const -> bool { return false; }
virtual auto kind() const -> std::string = 0;
virtual auto emitNewlineAfter() const -> bool = 0;
auto operator<=>(const BaseNode & rhs) const = default;
};
/**
* A node containing text. The text should be identical to how the node was
* written in the input file.
*/
struct TextNode : BaseNode {
std::string text;
explicit TextNode(std::string text) : text(text) {}
auto operator<=>(const TextNode & rhs) const = default;
};
std::ostream &operator<<(std::ostream &output, const TextNode &node);
// clang-format off
#define DECLARE_TEXT_NODE(NAME, NEEDS_NEWLINE, SHOULD_COMPARE) \
struct NAME : TextNode { \
using TextNode::TextNode; \
~NAME() override = default; \
\
auto kind() const -> std::string override { return #NAME; } \
auto emitNewlineAfter() const -> bool override { return NEEDS_NEWLINE; } \
auto shouldCompare() const -> bool override { return SHOULD_COMPARE; } \
auto operator<=>(const NAME & rhs) const = default; \
};
// clang-format on
/* name, needsNewline, shouldCompare */
DECLARE_TEXT_NODE(Prompt, false, false)
DECLARE_TEXT_NODE(Command, true, true)
DECLARE_TEXT_NODE(Output, true, true)
DECLARE_TEXT_NODE(Commentary, true, false)
DECLARE_TEXT_NODE(Args, true, false)
DECLARE_TEXT_NODE(Indent, false, false)
#undef DECLARE_TEXT_NODE
struct ShouldStart : BaseNode {
bool shouldStart;
ShouldStart(bool shouldStart) : shouldStart(shouldStart) {}
~ShouldStart() override = default;
auto emitNewlineAfter() const -> bool override { return true; }
auto kind() const -> std::string override { return "should-start"; }
auto operator<=>(const ShouldStart &rhs) const = default;
};
std::ostream &operator<<(std::ostream &output, const ShouldStart &node);
/**
* Any syntax node, including those that are cosmetic.
*/
using Node = std::variant<Prompt, Command, Output, Commentary, Args,
ShouldStart, Indent>;
/** Unparses a node into the exact text that would have created it, including a
* newline at the end if present, if withNewline is set */
void unparseNode(std::ostream &output, const Node &node,
bool withNewline = true);
std::string debugNode(const Node &node);
void debugPrint(std::ostream &output, std::vector<Node> &nodes);
/**
* Override gtest printing for lists of nodes.
*/
void PrintTo(std::vector<Node> const &nodes, std::ostream *output);
/**
* The result of parsing a test file.
*/
struct ParseResult {
/**
* A set of nodes that can be used to reproduce the input file. This is used
* to implement updating the test files.
*/
std::vector<Node> syntax;
/**
* Extra CLI arguments.
*/
std::vector<std::string> args;
/**
* Should the program start successfully?
*/
bool shouldStart = false;
/**
* Replace `$PWD` with the given value in `args`.
*/
void interpolatePwd(std::string_view pwd);
/**
* Tidy `syntax` to remove unnecessary nodes.
*/
auto tidyOutputForComparison() -> std::vector<Node>;
auto debugPrint(std::ostream &output) -> void;
};
/**
* A parse error.
*/
struct ParseError : BaseException {
std::string expected;
std::string rest;
ParseError(std::string expected, std::string rest)
: expected(expected), rest(rest) {}
const char *what() const noexcept override;
private:
/**
* Cached formatted contents of `what()`.
*/
mutable std::optional<std::string> what_;
};
struct Config {
/**
* The prompt string to look for.
*/
std::string prompt;
/**
* The number of spaces of indent for commands and output.
*/
size_t indent = 2;
};
/*
* A recursive descent parser for literate test cases for CLIs.
*
* FIXME: implement merging of these, so you can auto update cases that have
* comments.
*
* Syntax:
* ```
* ( COMMENTARY
* | INDENT PROMPT COMMAND
* | INDENT OUTPUT
* | @args ARGS
* | @should-start ( true | false )) *
* ```
*
* e.g.
* ```
* commentary commentary commentary
* @args --foo
* @should-start false
* nix-repl> :t 1
* an integer
* ```
*
* Yields something like:
* ```
* Commentary "commentary commentary commentary"
* Args "--foo"
* ShouldStart false
* Command ":t 1"
* Output "an integer"
* ```
*
* Note: one Output line is generated for each line of the sources, because
* this is effectively necessary to be able to align them in the future to
* auto-update tests.
*/
auto parse(std::string input, Config config) -> ParseResult;
}; // namespace cli_literate_parser
}; // namespace nix
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