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#pragma once
/**
* @file
* @brief Options for printing Nix values.
*/
#include <limits>
namespace nix {
/**
* How errors should be handled when printing values.
*/
enum class ErrorPrintBehavior {
/**
* Print the first line of the error in brackets: `«error: oh no!»`
*/
Print,
/**
* Throw the error to the code that attempted to print the value, instead
* of suppressing it it.
*/
Throw,
/**
* Only throw the error if encountered at the top level of the expression.
*
* This will cause expressions like `builtins.throw "uh oh!"` to throw
* errors, but will print attribute sets and other nested structures
* containing values that error (like `nixpkgs`) normally.
*/
ThrowTopLevel,
};
/**
* Options for printing Nix values.
*/
struct PrintOptions
{
/**
* If true, output ANSI color sequences.
*/
bool ansiColors = false;
/**
* If true, force values.
*/
bool force = false;
/**
* If true and `force` is set, print derivations as
* `«derivation /nix/store/...»` instead of as attribute sets.
*/
bool derivationPaths = false;
/**
* If true, track which values have been printed and skip them on
* subsequent encounters. Useful for self-referential values.
*/
bool trackRepeated = true;
/**
* Maximum depth to evaluate to.
*/
size_t maxDepth = std::numeric_limits<size_t>::max();
/**
* Maximum number of attributes in attribute sets to print.
*
* Note that this is a limit for the entire print invocation, not for each
* attribute set encountered.
*/
size_t maxAttrs = std::numeric_limits<size_t>::max();
/**
* Maximum number of list items to print.
*
* Note that this is a limit for the entire print invocation, not for each
* list encountered.
*/
size_t maxListItems = std::numeric_limits<size_t>::max();
/**
* Maximum string length to print.
*/
size_t maxStringLength = std::numeric_limits<size_t>::max();
/**
* Indentation width for pretty-printing.
*
* If set to 0 (the default), values are not pretty-printed.
*/
size_t prettyIndent = 0;
/**
* How to handle errors encountered while printing values.
*/
ErrorPrintBehavior errors = ErrorPrintBehavior::Print;
/**
* True if pretty-printing is enabled.
*/
inline bool shouldPrettyPrint()
{
return prettyIndent > 0;
}
};
/**
* `PrintOptions` for unknown and therefore potentially large values in error messages,
* to avoid printing "too much" output.
*/
static PrintOptions errorPrintOptions = PrintOptions {
.ansiColors = true,
.maxDepth = 10,
.maxAttrs = 10,
.maxListItems = 10,
.maxStringLength = 1024,
};
}
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