nix::EvalState Class Reference

Public Member Functions
	EvalState (const EvalState &)=delete
	EvalState (EvalState &&)=delete
EvalState &	operator= (const EvalState &)=delete
EvalState &	operator= (EvalState &&)=delete
void	evalFile (const SourcePath &path, Value &v)
void	resetFileCache ()
void	eval (Expr &e, Value &v)
bool	evalBool (Env &env, Expr &e)
void	evalAttrs (Env &env, Expr &e, Value &v)
void	evalList (Env &env, Expr &e, Value &v)
void	forceValue (Value &v, const PosIdx pos)
void	tryFixupBlackHolePos (Value &v, PosIdx pos)
void	forceValueDeep (Value &v)
NixInt	forceInt (Value &v, const PosIdx pos, std::string_view errorCtx)
NixFloat	forceFloat (Value &v, const PosIdx pos, std::string_view errorCtx)
bool	forceBool (Value &v, const PosIdx pos, std::string_view errorCtx)
void	forceAttrs (Value &v, const PosIdx pos, std::string_view errorCtx)
void	forceList (Value &v, const PosIdx pos, std::string_view errorCtx)
void	forceFunction (Value &v, const PosIdx pos, std::string_view errorCtx)
std::string_view	forceString (Value &v, const PosIdx pos, std::string_view errorCtx)
std::string_view	forceString (Value &v, NixStringContext &context, const PosIdx pos, std::string_view errorCtx)
std::string_view	forceStringNoCtx (Value &v, const PosIdx pos, std::string_view errorCtx)
StringMap	realiseContext (const NixStringContext &context)
bool	isDerivation (Value &v)
std::optional< std::string >	tryAttrsToString (const PosIdx pos, Value &v, NixStringContext &context, bool coerceMore=false, bool copyToStore=true)
BackedStringView	coerceToString (const PosIdx pos, Value &v, NixStringContext &context, std::string_view errorCtx, bool coerceMore=false, bool copyToStore=true, bool canonicalizePath=true)
SourcePath	coerceToPath (const PosIdx pos, Value &v, NixStringContext &context, std::string_view errorCtx)
StorePath	coerceToStorePath (const PosIdx pos, Value &v, NixStringContext &context, std::string_view errorCtx)
std::pair< SingleDerivedPath, std::string_view >	coerceToSingleDerivedPathUnchecked (const PosIdx pos, Value &v, std::string_view errorCtx)
SingleDerivedPath	coerceToSingleDerivedPath (const PosIdx pos, Value &v, std::string_view errorCtx)
bool	eqValues (Value &v1, Value &v2, const PosIdx pos, std::string_view errorCtx)
bool	isFunctor (Value &fun)
void	callFunction (Value &fun, size_t nrArgs, Value **args, Value &vRes, const PosIdx pos)
void	callFunction (Value &fun, Value &arg, Value &vRes, const PosIdx pos)
void	autoCallFunction (Bindings &args, Value &fun, Value &res, PosIdx pos)
void	mkPos (Value &v, PosIdx pos)
void	mkOutputString (Value &value, const SingleDerivedPath::Built &b, std::optional< StorePath > optStaticOutputPath, const ExperimentalFeatureSettings &xpSettings=experimentalFeatureSettings)
void	mkSingleDerivedPathString (const SingleDerivedPath &p, Value &v)
void	concatLists (Value &v, size_t nrLists, Value **lists, const PosIdx pos, std::string_view errorCtx)

Public Attributes
Evaluator &	ctx
AsyncIoRoot &	aio

Friends
class	Evaluator
struct	ExprVar
struct	ExprSet
struct	ExprLet

Member Function Documentation

autoCallFunction()

void nix::EvalState::autoCallFunction	(	Bindings &	args,
		Value &	fun,
		Value &	res,
		PosIdx	pos )

Automatically call a function for which each argument has a default value or has a binding in the args map.

coerceToPath()

SourcePath nix::EvalState::coerceToPath	(	const PosIdx	pos,
		Value &	v,
		NixStringContext &	context,
		std::string_view	errorCtx )

Path coercion.

Converts strings, paths and derivations to a path. The result is guaranteed to be a canonicalised, absolute path. Nothing is copied to the store.

coerceToSingleDerivedPath()

SingleDerivedPath nix::EvalState::coerceToSingleDerivedPath	(	const PosIdx	pos,
		Value &	v,
		std::string_view	errorCtx )

Coerce to SingleDerivedPath.

Must be a string which is either a literal store path or a "placeholder (see DownstreamPlaceholder).

Even more importantly, the string context must be exactly one element, which is either a NixStringContextElem::Opaque or NixStringContextElem::Built. (NixStringContextEleme::DrvDeep is not permitted).

The string is parsed based on the context — the context is the source of truth, and ultimately tells us what we want, and then we ensure the string corresponds to it.

coerceToSingleDerivedPathUnchecked()

std::pair< SingleDerivedPath, std::string_view > nix::EvalState::coerceToSingleDerivedPathUnchecked	(	const PosIdx	pos,
		Value &	v,
		std::string_view	errorCtx )

Part of coerceToSingleDerivedPath() without any store IO which is exposed for unit testing only.

coerceToStorePath()

StorePath nix::EvalState::coerceToStorePath	(	const PosIdx	pos,
		Value &	v,
		NixStringContext &	context,
		std::string_view	errorCtx )

Like coerceToPath, but the result must be a store path.

coerceToString()

BackedStringView nix::EvalState::coerceToString	(	const PosIdx	pos,
		Value &	v,
		NixStringContext &	context,
		std::string_view	errorCtx,
		bool	coerceMore = false,
		bool	copyToStore = true,
		bool	canonicalizePath = true )

String coercion.

Converts strings, paths and derivations to a string. If coerceMore is set, also converts nulls, integers, booleans and lists to a string. If copyToStore is set, referenced paths are copied to the Nix store as a side effect.

eqValues()

bool nix::EvalState::eqValues	(	Value &	v1,
		Value &	v2,
		const PosIdx	pos,
		std::string_view	errorCtx )

Do a deep equality test between two values. That is, list elements and attributes are compared recursively.

eval()

void nix::EvalState::eval	(	Expr &	e,
		Value &	v )

Evaluate an expression to normal form

Parameters

[out]

v

The resulting is stored here.

evalBool()

bool nix::EvalState::evalBool ( Env & env, Expr & e )

inline

Evaluation the expression, then verify that it has the expected type.

evalFile()

void nix::EvalState::evalFile	(	const SourcePath &	path,
		Value &	v )

Evaluate an expression read from the given file to normal form.

forceFunction()

void nix::EvalState::forceFunction	(	Value &	v,
		const PosIdx	pos,
		std::string_view	errorCtx )

Parameters

v	either lambda or primop

forceInt()

NixInt nix::EvalState::forceInt	(	Value &	v,
		const PosIdx	pos,
		std::string_view	errorCtx )

Force v, and then verify that it has the expected type.

forceValue()

void nix::EvalState::forceValue ( Value & v, const PosIdx pos )

inline

If v is a thunk, enter it and overwrite v with the result of the evaluation of the thunk. If v is a delayed function application, call the function and overwrite v with the result. Otherwise, this is a no-op.

forceValueDeep()

void nix::EvalState::forceValueDeep

(

Value &

v

)

Force a value, then recursively force list elements and attributes.

isDerivation()

bool nix::EvalState::isDerivation

(

Value &

v

)

Returns

true iff the value v denotes a derivation (i.e. a set with attribute type = "derivation").

mkOutputString()

void nix::EvalState::mkOutputString	(	Value &	value,
		const SingleDerivedPath::Built &	b,
		std::optional< StorePath >	optStaticOutputPath,
		const ExperimentalFeatureSettings &	xpSettings = experimentalFeatureSettings )

Create a string representing a SingleDerivedPath::Built.

The string is the printed store path with a context containing a single NixStringContextElem::Built element of the drv path and output name.

Parameters

value	Value we are settings
b	the drv whose output we are making a string for, and the output
optStaticOutputPath	Optional output path for that string. Must be passed if and only if output store object is input-addressed or fixed output. Will be printed to form string if passed, otherwise a placeholder will be used (see DownstreamPlaceholder).
xpSettings	Stop-gap to avoid globals during unit tests.

mkSingleDerivedPathString()

void nix::EvalState::mkSingleDerivedPathString	(	const SingleDerivedPath &	p,
		Value &	v )

Create a string representing a SingleDerivedPath.

A combination of mkStorePathString and mkOutputString.

realiseContext()

StringMap nix::EvalState::realiseContext ( const NixStringContext & context )

nodiscard

Realise the given context, and return a mapping from the placeholders used to construct the associated value to their final store path

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The documentation for this class was generated from the following files:

• lix/libexpr/eval.hh
• lix/libexpr/eval-inline.hh
• lix/libexpr/eval.cc
• lix/libexpr/primops.cc