#ifndef __EVAL_H
#define __EVAL_H
#include "value.hh"
#include "nixexpr.hh"
#include "symbol-table.hh"
#include "hash.hh"
#include <map>
#if HAVE_BOEHMGC
#include <gc/gc_allocator.h>
#endif
namespace nix {
class EvalState;
struct Attr;
/* Attribute sets are represented as a vector of attributes, sorted by
symbol (i.e. pointer to the attribute name in the symbol table). */
#if HAVE_BOEHMGC
typedef std::vector<Attr, gc_allocator<Attr> > BindingsBase;
#else
typedef std::vector<Attr> BindingsBase;
#endif
class Bindings : public BindingsBase
{
public:
iterator find(const Symbol & name);
void sort();
};
typedef void (* PrimOpFun) (EvalState & state, Value * * args, Value & v);
struct PrimOp
{
PrimOpFun fun;
unsigned int arity;
Symbol name;
PrimOp(PrimOpFun fun, unsigned int arity, Symbol name)
: fun(fun), arity(arity), name(name) { }
};
struct Env
{
Env * up;
unsigned int prevWith; // nr of levels up to next `with' environment
Value * values[0];
};
struct Attr
{
Symbol name;
Value * value;
Pos * pos;
Attr(Symbol name, Value * value, Pos * pos = &noPos)
: name(name), value(value), pos(pos) { };
Attr() : pos(&noPos) { };
bool operator < (const Attr & a) const
{
return name < a.name;
}
};
void mkString(Value & v, const string & s, const PathSet & context = PathSet());
void copyContext(const Value & v, PathSet & context);
/* Cache for calls to addToStore(); maps source paths to the store
paths. */
typedef std::map<Path, Path> SrcToStore;
struct EvalState;
std::ostream & operator << (std::ostream & str, const Value & v);
class EvalState
{
public:
SymbolTable symbols;
const Symbol sWith, sOutPath, sDrvPath, sType, sMeta, sName,
sSystem, sOverrides;
private:
SrcToStore srcToStore;
/* A cache from path names to parse trees. */
std::map<Path, Expr *> parseTrees;
/* A cache from path names to values. */
#if HAVE_BOEHMGC
typedef std::map<Path, Value, std::less<Path>, gc_allocator<std::pair<const Path, Value> > > FileEvalCache;
#else
typedef std::map<Path, Value> FileEvalCache;
#endif
FileEvalCache fileEvalCache;
typedef list<std::pair<string, Path> > SearchPath;
SearchPath searchPath;
SearchPath::iterator searchPathInsertionPoint;
public:
EvalState();
~EvalState();
void addToSearchPath(const string & s);
/* Parse a Nix expression from the specified file. If `path'
refers to a directory, then "/default.nix" is appended. */
Expr * parseExprFromFile(Path path);
/* Parse a Nix expression from the specified string. */
Expr * parseExprFromString(const string & s, const Path & basePath);
/* Evaluate an expression read from the given file to normal
form. */
void evalFile(const Path & path, Value & v);
/* Look up a file in the search path. */
Path findFile(const string & path);
/* Evaluate an expression to normal form, storing the result in
value `v'. */
void eval(Expr * e, Value & v);
/* Evaluation the expression, then verify that it has the expected
type. */
inline bool evalBool(Env & env, Expr * e);
inline void evalAttrs(Env & env, Expr * e, Value & v);
/* 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. */
inline void forceValue(Value & v);
/* Force a value, then recursively force list elements and
attributes. */
void strictForceValue(Value & v);
/* Force `v', and then verify that it has the expected type. */
int forceInt(Value & v);
bool forceBool(Value & v);
inline void forceAttrs(Value & v);
inline void forceList(Value & v);
void forceFunction(Value & v); // either lambda or primop
string forceString(Value & v);
string forceString(Value & v, PathSet & context);
string forceStringNoCtx(Value & v);
/* Return true iff the value `v' denotes a derivation (i.e. a
set with attribute `type = "derivation"'). */
bool isDerivation(Value & v);
/* 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.q */
string coerceToString(Value & v, PathSet & context,
bool coerceMore = false, bool copyToStore = true);
/* 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. */
Path coerceToPath(Value & v, PathSet & context);
private:
/* The base environment, containing the builtin functions and
values. */
Env & baseEnv;
unsigned int baseEnvDispl;
public:
/* The same, but used during parsing to resolve variables. */
StaticEnv staticBaseEnv; // !!! should be private
private:
void createBaseEnv();
void addConstant(const string & name, Value & v);
void addPrimOp(const string & name,
unsigned int arity, PrimOpFun primOp);
inline Value * lookupVar(Env * env, const VarRef & var);
friend class ExprVar;
friend class ExprAttrs;
friend class ExprLet;
Expr * parse(const char * text,
const Path & path, const Path & basePath);
public:
/* Do a deep equality test between two values. That is, list
elements and attributes are compared recursively. */
bool eqValues(Value & v1, Value & v2);
void callFunction(Value & fun, Value & arg, Value & v);
/* Automatically call a function for which each argument has a
default value or has a binding in the `args' map. */
void autoCallFunction(Bindings & args, Value & fun, Value & res);
/* Allocation primitives. */
Value * allocValue();
Env & allocEnv(unsigned int size);
Value * allocAttr(Value & vAttrs, const Symbol & name);
void mkList(Value & v, unsigned int length);
void mkAttrs(Value & v, unsigned int expected);
void mkThunk_(Value & v, Expr * expr);
/* Print statistics. */
void printStats();
private:
unsigned long nrEnvs;
unsigned long nrValuesInEnvs;
unsigned long nrValues;
unsigned long nrListElems;
unsigned long nrAttrsets;
unsigned long nrOpUpdates;
unsigned long nrOpUpdateValuesCopied;
friend class RecursionCounter;
friend class ExprOpUpdate;
};
/* Return a string representing the type of the value `v'. */
string showType(const Value & v);
}
#endif /* !__EVAL_H */
