nix-super/src/libexpr/print.hh
Alex Ameen b72bc4a972
libexpr: quote reserved keys when printing
This fixes a bug in commands like `nix eval' which would emit invalid attribute
sets if they contained reserved keywords such as "assert", "let", etc.

These keywords will not be quoted when printed, making them valid expressions.
All keywords recognized by the lexer are quoted except "or", which does not
require quotation.
2023-05-09 09:45:12 -05:00

54 lines
1.8 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>
namespace nix {
/**
* Print a string as a Nix string literal.
*
* Quotes and fairly minimal escaping are added.
*
* @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);
}