lix/src/libexpr/print.hh
eldritch horrors b221a14f0a Merge pull request #9925 from 9999years/fmt-cleanup
Cleanup `fmt.hh`

(cherry picked from commit 47a1dbb4b8e7913cbb9b4d604728b912e76e4ca0)
Change-Id: Id076a45cb39652f437fe3f8bda10c310a9894777
2024-03-09 07:00:13 -07:00

92 lines
2.6 KiB
C++

#pragma once
/**
* @file
* @brief Common printing functions for the Nix language
*
* While most types come with their own methods for printing, they share some
* functions that are placed here.
*/
#include <iostream>
#include "fmt.hh"
#include "print-options.hh"
namespace nix {
class EvalState;
struct Value;
/**
* Print a string as a Nix string literal.
*
* Quotes and fairly minimal escaping are added.
*
* @param o The output stream to print to
* @param s The logical string
*/
std::ostream & printLiteralString(std::ostream & o, std::string_view s);
inline std::ostream & printLiteralString(std::ostream & o, const char * s) {
return printLiteralString(o, std::string_view(s));
}
inline std::ostream & printLiteralString(std::ostream & o, const std::string & s) {
return printLiteralString(o, std::string_view(s));
}
/** Print `true` or `false`. */
std::ostream & printLiteralBool(std::ostream & o, bool b);
/**
* Print a string as an attribute name in the Nix expression language syntax.
*
* Prints a quoted string if necessary.
*/
std::ostream & printAttributeName(std::ostream & o, std::string_view s);
/**
* Returns `true' is a string is a reserved keyword which requires quotation
* when printing attribute set field names.
*/
bool isReservedKeyword(const std::string_view str);
/**
* Print a string as an identifier in the Nix expression language syntax.
*
* FIXME: "identifier" is ambiguous. Identifiers do not have a single
* textual representation. They can be used in variable references,
* let bindings, left-hand sides or attribute names in a select
* expression, or something else entirely, like JSON. Use one of the
* `print*` functions instead.
*/
std::ostream & printIdentifier(std::ostream & o, std::string_view s);
void printValue(EvalState & state, std::ostream & str, Value & v, PrintOptions options = PrintOptions {});
/**
* A partially-applied form of `printValue` which can be formatted using `<<`
* without allocating an intermediate string.
*/
class ValuePrinter {
friend std::ostream & operator << (std::ostream & output, const ValuePrinter & printer);
private:
EvalState & state;
Value & value;
PrintOptions options;
public:
ValuePrinter(EvalState & state, Value & value, PrintOptions options = PrintOptions {})
: state(state), value(value), options(options) { }
};
std::ostream & operator<<(std::ostream & output, const ValuePrinter & printer);
/**
* `ValuePrinter` does its own ANSI formatting, so we don't color it
* magenta.
*/
template<>
HintFmt & HintFmt::operator%(const ValuePrinter & value);
}