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* Started integrating the new evaluator.

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This commit is contained in:
Eelco Dolstra 2010-03-29 14:37:56 +00:00
parent 52090d2418
commit 31428c3a06
8 changed files with 745 additions and 709 deletions
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2
src/libexpr/attr-path.cc
View file

@ -6,6 +6,7 @@
namespace nix {
#if 0
bool isAttrs(EvalState & state, Expr e, ATermMap & attrs)
{
e = evalExpr(state, e);
@ -77,6 +78,7 @@ Expr findAlongAttrPath(EvalState & state, const string & attrPath,
return e;
}
#endif
}

662
src/libexpr/eval-test.cc
View file

@ -10,668 +10,13 @@
using namespace nix;
struct Env;
struct Value;
typedef ATerm Sym;
typedef std::map<Sym, Value> Bindings;
struct Env
{
Env * up;
Bindings bindings;
};
typedef enum {
tInt = 1,
tBool,
tString,
tPath,
tNull,
tAttrs,
tList,
tThunk,
tLambda,
tCopy,
tBlackhole,
tPrimOp,
tPrimOpApp,
} ValueType;
typedef void (* PrimOp_) (Value * * args, Value & v);
struct Value
{
ValueType type;
union
{
int integer;
bool boolean;
struct {
const char * s;
const char * * context;
} string;
Bindings * attrs;
struct {
unsigned int length;
Value * elems;
} list;
struct {
Env * env;
Expr expr;
} thunk;
struct {
Env * env;
Pattern pat;
Expr body;
} lambda;
Value * val;
struct {
PrimOp_ fun;
unsigned int arity;
} primOp;
struct {
Value * left, * right;
unsigned int argsLeft;
} primOpApp;
};
};
static void mkThunk(Value & v, Env & env, Expr expr)
{
v.type = tThunk;
v.thunk.env = &env;
v.thunk.expr = expr;
}
static void mkInt(Value & v, int n)
{
v.type = tInt;
v.integer = n;
}
static void mkBool(Value & v, bool b)
{
v.type = tBool;
v.boolean = b;
}
static void mkString(Value & v, const char * s)
{
v.type = tString;
v.string.s = s;
v.string.context = 0;
}
std::ostream & operator << (std::ostream & str, Value & v)
{
switch (v.type) {
case tInt:
str << v.integer;
break;
case tBool:
str << (v.boolean ? "true" : "false");
break;
case tString:
str << "\"" << v.string.s << "\""; // !!! escaping
break;
case tNull:
str << "true";
break;
case tAttrs:
str << "{ ";
foreach (Bindings::iterator, i, *v.attrs)
str << aterm2String(i->first) << " = " << i->second << "; ";
str << "}";
break;
case tList:
str << "[ ";
for (unsigned int n = 0; n < v.list.length; ++n)
str << v.list.elems[n] << " ";
str << "]";
break;
case tThunk:
str << "<CODE>";
break;
case tLambda:
str << "<LAMBDA>";
break;
case tPrimOp:
str << "<PRIMOP>";
break;
case tPrimOpApp:
str << "<PRIMOP-APP>";
break;
default:
abort();
}
return str;
}
static void eval(Env & env, Expr e, Value & v);
string showType(Value & v)
{
switch (v.type) {
case tString: return "a string";
case tPath: return "a path";
case tNull: return "null";
case tInt: return "an integer";
case tBool: return "a boolean";
case tLambda: return "a function";
case tAttrs: return "an attribute set";
case tList: return "a list";
case tPrimOpApp: return "a partially applied built-in function";
default: throw Error("unknown type");
}
}
static void forceValue(Value & v)
{
if (v.type == tThunk) {
v.type = tBlackhole;
eval(*v.thunk.env, v.thunk.expr, v);
}
else if (v.type == tCopy) {
forceValue(*v.val);
v = *v.val;
}
else if (v.type == tBlackhole)
throw EvalError("infinite recursion encountered");
}
static void forceInt(Value & v)
{
forceValue(v);
if (v.type != tInt)
throw TypeError(format("value is %1% while an integer was expected") % showType(v));
}
static void forceAttrs(Value & v)
{
forceValue(v);
if (v.type != tAttrs)
throw TypeError(format("value is %1% while an attribute set was expected") % showType(v));
}
static void forceList(Value & v)
{
forceValue(v);
if (v.type != tList)
throw TypeError(format("value is %1% while a list was expected") % showType(v));
}
static Value * lookupWith(Env * env, Sym name)
{
if (!env) return 0;
Value * v = lookupWith(env->up, name);
if (v) return v;
Bindings::iterator i = env->bindings.find(sWith);
if (i == env->bindings.end()) return 0;
Bindings::iterator j = i->second.attrs->find(name);
if (j != i->second.attrs->end()) return &j->second;
return 0;
}
static Value * lookupVar(Env * env, Sym name)
{
/* First look for a regular variable binding for `name'. */
for (Env * env2 = env; env2; env2 = env2->up) {
Bindings::iterator i = env2->bindings.find(name);
if (i != env2->bindings.end()) return &i->second;
}
/* Otherwise, look for a `with' attribute set containing `name'.
Outer `withs' take precedence (i.e. `with {x=1;}; with {x=2;};
x' evaluates to 1). */
Value * v = lookupWith(env, name);
if (v) return v;
/* Alternative implementation where the inner `withs' take
precedence (i.e. `with {x=1;}; with {x=2;}; x' evaluates to
2). */
#if 0
for (Env * env2 = env; env2; env2 = env2->up) {
Bindings::iterator i = env2->bindings.find(sWith);
if (i == env2->bindings.end()) continue;
Bindings::iterator j = i->second.attrs->find(name);
if (j != i->second.attrs->end()) return &j->second;
}
#endif
throw Error("undefined variable");
}
static bool eqValues(Value & v1, Value & v2)
{
forceValue(v1);
forceValue(v2);
switch (v1.type) {
case tInt:
return v2.type == tInt && v1.integer == v2.integer;
case tBool:
return v2.type == tBool && v1.boolean == v2.boolean;
case tList:
if (v2.type != tList || v1.list.length != v2.list.length) return false;
for (unsigned int n = 0; n < v1.list.length; ++n)
if (!eqValues(v1.list.elems[n], v2.list.elems[n])) return false;
return true;
case tAttrs: {
if (v2.type != tAttrs || v1.attrs->size() != v2.attrs->size()) return false;
Bindings::iterator i, j;
for (i = v1.attrs->begin(), j = v2.attrs->begin(); i != v1.attrs->end(); ++i, ++j)
if (!eqValues(i->second, j->second)) return false;
return true;
}
default:
throw Error("cannot compare given values");
}
}
unsigned long nrValues = 0, nrEnvs = 0, nrEvaluated = 0;
static Value * allocValues(unsigned int count)
{
nrValues += count;
return new Value[count]; // !!! check destructor
}
static Env & allocEnv()
{
nrEnvs++;
return *(new Env);
}
char * p1 = 0, * p2 = 0;
static bool evalBool(Env & env, Expr e)
{
Value v;
eval(env, e, v);
if (v.type != tBool)
throw TypeError(format("value is %1% while a Boolean was expected") % showType(v));
return v.boolean;
}
static void eval(Env & env, Expr e, Value & v)
{
char c;
if (!p1) p1 = &c; else if (!p2) p2 = &c;
printMsg(lvlError, format("eval: %1%") % e);
nrEvaluated++;
Sym name;
if (matchVar(e, name)) {
Value * v2 = lookupVar(&env, name);
forceValue(*v2);
v = *v2;
return;
}
int n;
if (matchInt(e, n)) {
mkInt(v, n);
return;
}
ATerm s; ATermList context;
if (matchStr(e, s, context)) {
assert(context == ATempty);
mkString(v, ATgetName(ATgetAFun(s)));
return;
}
ATermList es;
if (matchAttrs(e, es)) {
v.type = tAttrs;
v.attrs = new Bindings;
ATerm e2, pos;
for (ATermIterator i(es); i; ++i) {
if (!matchBind(*i, name, e2, pos)) abort(); /* can't happen */
Value & v2 = (*v.attrs)[name];
nrValues++;
mkThunk(v2, env, e2);
}
return;
}
ATermList rbnds, nrbnds;
if (matchRec(e, rbnds, nrbnds)) {
Env & env2(allocEnv());
env2.up = &env;
v.type = tAttrs;
v.attrs = &env2.bindings;
ATerm name, e2, pos;
for (ATermIterator i(rbnds); i; ++i) {
if (!matchBind(*i, name, e2, pos)) abort(); /* can't happen */
Value & v2 = env2.bindings[name];
nrValues++;
mkThunk(v2, env2, e2);
}
return;
}
Expr e1, e2;
if (matchSelect(e, e2, name)) {
eval(env, e2, v);
forceAttrs(v); // !!! eval followed by force is slightly inefficient
Bindings::iterator i = v.attrs->find(name);
if (i == v.attrs->end()) throw TypeError("attribute not found");
forceValue(i->second);
v = i->second;
return;
}
Pattern pat; Expr body; Pos pos;
if (matchFunction(e, pat, body, pos)) {
v.type = tLambda;
v.lambda.env = &env;
v.lambda.pat = pat;
v.lambda.body = body;
return;
}
Expr fun, arg;
if (matchCall(e, fun, arg)) {
eval(env, fun, v);
if (v.type == tPrimOp || v.type == tPrimOpApp) {
unsigned int argsLeft =
v.type == tPrimOp ? v.primOp.arity : v.primOpApp.argsLeft;
if (argsLeft == 1) {
/* We have all the arguments, so call the primop.
First find the primop. */
Value * primOp = &v;
while (primOp->type == tPrimOpApp) primOp = primOp->primOpApp.left;
assert(primOp->type == tPrimOp);
unsigned int arity = primOp->primOp.arity;
Value vLastArg;
mkThunk(vLastArg, env, arg);
/* Put all the arguments in an array. */
Value * vArgs[arity];
unsigned int n = arity - 1;
vArgs[n--] = &vLastArg;
for (Value * arg = &v; arg->type == tPrimOpApp; arg = arg->primOpApp.left)
vArgs[n--] = arg->primOpApp.right;
/* And call the primop. */
primOp->primOp.fun(vArgs, v);
} else {
Value * v2 = allocValues(2);
v2[0] = v;
mkThunk(v2[1], env, arg);
v.type = tPrimOpApp;
v.primOpApp.left = &v2[0];
v.primOpApp.right = &v2[1];
v.primOpApp.argsLeft = argsLeft - 1;
}
return;
}
if (v.type != tLambda) throw TypeError("expected function");
Env & env2(allocEnv());
env2.up = &env;
ATermList formals; ATerm ellipsis;
if (matchVarPat(v.lambda.pat, name)) {
Value & vArg = env2.bindings[name];
nrValues++;
mkThunk(vArg, env, arg);
}
else if (matchAttrsPat(v.lambda.pat, formals, ellipsis, name)) {
Value * vArg;
Value vArg_;
if (name == sNoAlias)
vArg = &vArg_;
else {
vArg = &env2.bindings[name];
nrValues++;
}
eval(env, arg, *vArg);
forceAttrs(*vArg);
/* For each formal argument, get the actual argument. If
there is no matching actual argument but the formal
argument has a default, use the default. */
unsigned int attrsUsed = 0;
for (ATermIterator i(formals); i; ++i) {
Expr def; Sym name;
DefaultValue def2;
if (!matchFormal(*i, name, def2)) abort(); /* can't happen */
Bindings::iterator j = vArg->attrs->find(name);
Value & v = env2.bindings[name];
nrValues++;
if (j == vArg->attrs->end()) {
if (!matchDefaultValue(def2, def)) def = 0;
if (def == 0) throw TypeError(format("the argument named `%1%' required by the function is missing")
% aterm2String(name));
mkThunk(v, env2, def);
} else {
attrsUsed++;
v.type = tCopy;
v.val = &j->second;
}
}
/* Check that each actual argument is listed as a formal
argument (unless the attribute match specifies a
`...'). TODO: show the names of the
expected/unexpected arguments. */
if (ellipsis == eFalse && attrsUsed != vArg->attrs->size())
throw TypeError("function called with unexpected argument");
}
else abort();
eval(env2, v.lambda.body, v);
return;
}
Expr attrs;
if (matchWith(e, attrs, body, pos)) {
Env & env2(allocEnv());
env2.up = &env;
Value & vAttrs = env2.bindings[sWith];
nrValues++;
eval(env, attrs, vAttrs);
forceAttrs(vAttrs);
eval(env2, body, v);
return;
}
if (matchList(e, es)) {
v.type = tList;
v.list.length = ATgetLength(es);
v.list.elems = allocValues(v.list.length);
for (unsigned int n = 0; n < v.list.length; ++n, es = ATgetNext(es))
mkThunk(v.list.elems[n], env, ATgetFirst(es));
return;
}
if (matchOpEq(e, e1, e2)) {
Value v1; eval(env, e1, v1);
Value v2; eval(env, e2, v2);
mkBool(v, eqValues(v1, v2));
return;
}
if (matchOpNEq(e, e1, e2)) {
Value v1; eval(env, e1, v1);
Value v2; eval(env, e2, v2);
mkBool(v, !eqValues(v1, v2));
return;
}
if (matchOpConcat(e, e1, e2)) {
Value v1; eval(env, e1, v1);
forceList(v1);
Value v2; eval(env, e2, v2);
forceList(v2);
v.type = tList;
v.list.length = v1.list.length + v2.list.length;
v.list.elems = allocValues(v.list.length);
/* !!! This loses sharing with the original lists. We could
use a tCopy node, but that would use more memory. */
for (unsigned int n = 0; n < v1.list.length; ++n)
v.list.elems[n] = v1.list.elems[n];
for (unsigned int n = 0; n < v2.list.length; ++n)
v.list.elems[n + v1.list.length] = v2.list.elems[n];
return;
}
if (matchConcatStrings(e, es)) {
unsigned int n = ATgetLength(es), j = 0;
Value vs[n];
unsigned int len = 0;
for (ATermIterator i(es); i; ++i, ++j) {
eval(env, *i, vs[j]);
if (vs[j].type != tString) throw TypeError("string expected");
len += strlen(vs[j].string.s);
}
char * s = new char[len + 1], * t = s;
for (unsigned int i = 0; i < j; ++i) {
strcpy(t, vs[i].string.s);
t += strlen(vs[i].string.s);
}
*t = 0;
mkString(v, s);
return;
}
Expr e3;
if (matchIf(e, e1, e2, e3)) {
eval(env, evalBool(env, e1) ? e2 : e3, v);
return;
}
if (matchOpOr(e, e1, e2)) {
mkBool(v, evalBool(env, e1) || evalBool(env, e2));
return;
}
throw Error("unsupported term");
}
static void strictEval(Env & env, Expr e, Value & v)
{
eval(env, e, v);
if (v.type == tAttrs) {
foreach (Bindings::iterator, i, *v.attrs)
forceValue(i->second);
}
else if (v.type == tList) {
for (unsigned int n = 0; n < v.list.length; ++n)
forceValue(v.list.elems[n]);
}
}
static void prim_head(Value * * args, Value & v)
{
forceList(*args[0]);
if (args[0]->list.length == 0)
throw Error("`head' called on an empty list");
forceValue(args[0]->list.elems[0]);
v = args[0]->list.elems[0];
}
static void prim_add(Value * * args, Value & v)
{
forceInt(*args[0]);
forceInt(*args[1]);
mkInt(v, args[0]->integer + args[1]->integer);
}
static void addPrimOp(Env & env, const string & name, unsigned int arity, PrimOp_ fun)
{
Value & v = env.bindings[toATerm(name)];
nrValues++;
v.type = tPrimOp;
v.primOp.arity = arity;
v.primOp.fun = fun;
}
void doTest(string s)
{
Env baseEnv;
baseEnv.up = 0;
/* Add global constants such as `true' to the base environment. */
{
Value & v = baseEnv.bindings[toATerm("true")];
v.type = tBool;
v.boolean = true;
}
{
Value & v = baseEnv.bindings[toATerm("false")];
v.type = tBool;
v.boolean = false;
}
{
Value & v = baseEnv.bindings[toATerm("null")];
v.type = tNull;
}
/* Add primops to the base environment. */
addPrimOp(baseEnv, "__head", 1, prim_head);
addPrimOp(baseEnv, "__add", 2, prim_add);
p1 = p2 = 0;
EvalState state;
Expr e = parseExprFromString(state, s, "/");
printMsg(lvlError, format(">>>>> %1%") % e);
Value v;
strictEval(baseEnv, e, v);
state.strictEval(e, v);
printMsg(lvlError, format("result: %1%") % v);
}
@ -721,11 +66,6 @@ void run(Strings args)
doTest("if false then 1 else 2");
doTest("if false || true then 1 else 2");
doTest("let x = x; in if true || x then 1 else 2");
printMsg(lvlError, format("alloced %1% values") % nrValues);
printMsg(lvlError, format("alloced %1% environments") % nrEnvs);
printMsg(lvlError, format("evaluated %1% expressions") % nrEvaluated);
printMsg(lvlError, format("each eval() uses %1% bytes of stack space") % (p1 - p2));
}

564
src/libexpr/eval.cc
View file

@ -7,6 +7,8 @@
#include "nixexpr-ast.hh"
#include "globals.hh"
#include <cstring>
#define LocalNoInline(f) static f __attribute__((noinline)); f
#define LocalNoInlineNoReturn(f) static f __attribute__((noinline, noreturn)); f
@ -15,15 +17,77 @@
namespace nix {
EvalState::EvalState()
: normalForms(32768), primOps(128)
std::ostream & operator << (std::ostream & str, Value & v)
{
nrEvaluated = nrCached = 0;
switch (v.type) {
case tInt:
str << v.integer;
break;
case tBool:
str << (v.boolean ? "true" : "false");
break;
case tString:
str << "\"" << v.string.s << "\""; // !!! escaping
break;
case tNull:
str << "true";
break;
case tAttrs:
str << "{ ";
foreach (Bindings::iterator, i, *v.attrs)
str << aterm2String(i->first) << " = " << i->second << "; ";
str << "}";
break;
case tList:
str << "[ ";
for (unsigned int n = 0; n < v.list.length; ++n)
str << v.list.elems[n] << " ";
str << "]";
break;
case tThunk:
str << "<CODE>";
break;
case tLambda:
str << "<LAMBDA>";
break;
case tPrimOp:
str << "<PRIMOP>";
break;
case tPrimOpApp:
str << "<PRIMOP-APP>";
break;
default:
throw Error("invalid value");
}
return str;
}
string showType(Value & v)
{
switch (v.type) {
case tString: return "a string";
case tPath: return "a path";
case tNull: return "null";
case tInt: return "an integer";
case tBool: return "a boolean";
case tLambda: return "a function";
case tAttrs: return "an attribute set";
case tList: return "a list";
case tPrimOpApp: return "a partially applied built-in function";
default: throw Error("unknown type");
}
}
EvalState::EvalState() : baseEnv(allocEnv())
{
nrValues = nrEnvs = nrEvaluated = 0;
initNixExprHelpers();
addPrimOps();
createBaseEnv();
allowUnsafeEquality = getEnv("NIX_NO_UNSAFE_EQ", "") == "";
}
@ -31,7 +95,11 @@ EvalState::EvalState()
void EvalState::addPrimOp(const string & name,
unsigned int arity, PrimOp primOp)
{
primOps.set(toATerm(name), makePrimOpDef(arity, ATmakeBlob(0, (void *) primOp)));
Value & v = baseEnv.bindings[toATerm(name)];
nrValues++;
v.type = tPrimOp;
v.primOp.arity = arity;
v.primOp.fun = primOp;
}
@ -76,6 +144,471 @@ LocalNoInline(void addErrorPrefix(Error & e, const char * s, const string & s2,
}
static void mkThunk(Value & v, Env & env, Expr expr)
{
v.type = tThunk;
v.thunk.env = &env;
v.thunk.expr = expr;
}
static Value * lookupWith(Env * env, Sym name)
{
if (!env) return 0;
Value * v = lookupWith(env->up, name);
if (v) return v;
Bindings::iterator i = env->bindings.find(sWith);
if (i == env->bindings.end()) return 0;
Bindings::iterator j = i->second.attrs->find(name);
if (j != i->second.attrs->end()) return &j->second;
return 0;
}
static Value * lookupVar(Env * env, Sym name)
{
/* First look for a regular variable binding for `name'. */
for (Env * env2 = env; env2; env2 = env2->up) {
Bindings::iterator i = env2->bindings.find(name);
if (i != env2->bindings.end()) return &i->second;
}
/* Otherwise, look for a `with' attribute set containing `name'.
Outer `withs' take precedence (i.e. `with {x=1;}; with {x=2;};
x' evaluates to 1). */
Value * v = lookupWith(env, name);
if (v) return v;
/* Alternative implementation where the inner `withs' take
precedence (i.e. `with {x=1;}; with {x=2;}; x' evaluates to
2). */
#if 0
for (Env * env2 = env; env2; env2 = env2->up) {
Bindings::iterator i = env2->bindings.find(sWith);
if (i == env2->bindings.end()) continue;
Bindings::iterator j = i->second.attrs->find(name);
if (j != i->second.attrs->end()) return &j->second;
}
#endif
throw Error("undefined variable");
}
Value * EvalState::allocValues(unsigned int count)
{
nrValues += count;
return new Value[count]; // !!! check destructor
}
Env & EvalState::allocEnv()
{
nrEnvs++;
return *(new Env);
}
static char * deepestStack = (char *) -1; /* for measuring stack usage */
void EvalState::eval(Env & env, Expr e, Value & v)
{
/* When changing this function, make sure that you don't cause a
(large) increase in stack consumption! */
char x;
if (&x < deepestStack) deepestStack = &x;
printMsg(lvlError, format("eval: %1%") % e);
nrEvaluated++;
Sym name;
if (matchVar(e, name)) {
Value * v2 = lookupVar(&env, name);
forceValue(*v2);
v = *v2;
return;
}
int n;
if (matchInt(e, n)) {
mkInt(v, n);
return;
}
ATerm s; ATermList context;
if (matchStr(e, s, context)) {
assert(context == ATempty);
mkString(v, ATgetName(ATgetAFun(s)));
return;
}
ATermList es;
if (matchAttrs(e, es)) {
v.type = tAttrs;
v.attrs = new Bindings;
ATerm e2, pos;
for (ATermIterator i(es); i; ++i) {
if (!matchBind(*i, name, e2, pos)) abort(); /* can't happen */
Value & v2 = (*v.attrs)[name];
nrValues++;
mkThunk(v2, env, e2);
}
return;
}
ATermList rbnds, nrbnds;
if (matchRec(e, rbnds, nrbnds)) {
Env & env2(allocEnv());
env2.up = &env;
v.type = tAttrs;
v.attrs = &env2.bindings;
ATerm name, e2, pos;
for (ATermIterator i(rbnds); i; ++i) {
if (!matchBind(*i, name, e2, pos)) abort(); /* can't happen */
Value & v2 = env2.bindings[name];
nrValues++;
mkThunk(v2, env2, e2);
}
return;
}
Expr e1, e2;
if (matchSelect(e, e2, name)) {
eval(env, e2, v);
forceAttrs(v); // !!! eval followed by force is slightly inefficient
Bindings::iterator i = v.attrs->find(name);
if (i == v.attrs->end()) throw TypeError("attribute not found");
forceValue(i->second);
v = i->second;
return;
}
Pattern pat; Expr body; Pos pos;
if (matchFunction(e, pat, body, pos)) {
v.type = tLambda;
v.lambda.env = &env;
v.lambda.pat = pat;
v.lambda.body = body;
return;
}
Expr fun, arg;
if (matchCall(e, fun, arg)) {
eval(env, fun, v);
if (v.type == tPrimOp || v.type == tPrimOpApp) {
unsigned int argsLeft =
v.type == tPrimOp ? v.primOp.arity : v.primOpApp.argsLeft;
if (argsLeft == 1) {
/* We have all the arguments, so call the primop.
First find the primop. */
Value * primOp = &v;
while (primOp->type == tPrimOpApp) primOp = primOp->primOpApp.left;
assert(primOp->type == tPrimOp);
unsigned int arity = primOp->primOp.arity;
Value vLastArg;
mkThunk(vLastArg, env, arg);
/* Put all the arguments in an array. */
Value * vArgs[arity];
unsigned int n = arity - 1;
vArgs[n--] = &vLastArg;
for (Value * arg = &v; arg->type == tPrimOpApp; arg = arg->primOpApp.left)
vArgs[n--] = arg->primOpApp.right;
/* And call the primop. */
primOp->primOp.fun(*this, vArgs, v);
} else {
Value * v2 = allocValues(2);
v2[0] = v;
mkThunk(v2[1], env, arg);
v.type = tPrimOpApp;
v.primOpApp.left = &v2[0];
v.primOpApp.right = &v2[1];
v.primOpApp.argsLeft = argsLeft - 1;
}
return;
}
if (v.type != tLambda) throw TypeError("expected function");
Env & env2(allocEnv());
env2.up = &env;
ATermList formals; ATerm ellipsis;
if (matchVarPat(v.lambda.pat, name)) {
Value & vArg = env2.bindings[name];
nrValues++;
mkThunk(vArg, env, arg);
}
else if (matchAttrsPat(v.lambda.pat, formals, ellipsis, name)) {
Value * vArg;
Value vArg_;
if (name == sNoAlias)
vArg = &vArg_;
else {
vArg = &env2.bindings[name];
nrValues++;
}
eval(env, arg, *vArg);
forceAttrs(*vArg);
/* For each formal argument, get the actual argument. If
there is no matching actual argument but the formal
argument has a default, use the default. */
unsigned int attrsUsed = 0;
for (ATermIterator i(formals); i; ++i) {
Expr def; Sym name;
DefaultValue def2;
if (!matchFormal(*i, name, def2)) abort(); /* can't happen */
Bindings::iterator j = vArg->attrs->find(name);
Value & v = env2.bindings[name];
nrValues++;
if (j == vArg->attrs->end()) {
if (!matchDefaultValue(def2, def)) def = 0;
if (def == 0) throw TypeError(format("the argument named `%1%' required by the function is missing")
% aterm2String(name));
mkThunk(v, env2, def);
} else {
attrsUsed++;
v.type = tCopy;
v.val = &j->second;
}
}
/* Check that each actual argument is listed as a formal
argument (unless the attribute match specifies a
`...'). TODO: show the names of the
expected/unexpected arguments. */
if (ellipsis == eFalse && attrsUsed != vArg->attrs->size())
throw TypeError("function called with unexpected argument");
}
else abort();
eval(env2, v.lambda.body, v);
return;
}
Expr attrs;
if (matchWith(e, attrs, body, pos)) {
Env & env2(allocEnv());
env2.up = &env;
Value & vAttrs = env2.bindings[sWith];
nrValues++;
eval(env, attrs, vAttrs);
forceAttrs(vAttrs);
eval(env2, body, v);
return;
}
if (matchList(e, es)) {
v.type = tList;
v.list.length = ATgetLength(es);
v.list.elems = allocValues(v.list.length);
for (unsigned int n = 0; n < v.list.length; ++n, es = ATgetNext(es))
mkThunk(v.list.elems[n], env, ATgetFirst(es));
return;
}
if (matchOpEq(e, e1, e2)) {
Value v1; eval(env, e1, v1);
Value v2; eval(env, e2, v2);
mkBool(v, eqValues(v1, v2));
return;
}
if (matchOpNEq(e, e1, e2)) {
Value v1; eval(env, e1, v1);
Value v2; eval(env, e2, v2);
mkBool(v, !eqValues(v1, v2));
return;
}
if (matchOpConcat(e, e1, e2)) {
Value v1; eval(env, e1, v1);
forceList(v1);
Value v2; eval(env, e2, v2);
forceList(v2);
v.type = tList;
v.list.length = v1.list.length + v2.list.length;
v.list.elems = allocValues(v.list.length);
/* !!! This loses sharing with the original lists. We could
use a tCopy node, but that would use more memory. */
for (unsigned int n = 0; n < v1.list.length; ++n)
v.list.elems[n] = v1.list.elems[n];
for (unsigned int n = 0; n < v2.list.length; ++n)
v.list.elems[n + v1.list.length] = v2.list.elems[n];
return;
}
if (matchConcatStrings(e, es)) {
unsigned int n = ATgetLength(es), j = 0;
Value vs[n];
unsigned int len = 0;
for (ATermIterator i(es); i; ++i, ++j) {
eval(env, *i, vs[j]);
if (vs[j].type != tString) throw TypeError("string expected");
len += strlen(vs[j].string.s);
}
char * s = new char[len + 1], * t = s;
for (unsigned int i = 0; i < j; ++i) {
strcpy(t, vs[i].string.s);
t += strlen(vs[i].string.s);
}
*t = 0;
mkString(v, s);
return;
}
Expr e3;
if (matchIf(e, e1, e2, e3)) {
eval(env, evalBool(env, e1) ? e2 : e3, v);
return;
}
if (matchOpOr(e, e1, e2)) {
mkBool(v, evalBool(env, e1) || evalBool(env, e2));
return;
}
throw Error("unsupported term");
}
void EvalState::eval(Expr e, Value & v)
{
eval(baseEnv, e, v);
}
bool EvalState::evalBool(Env & env, Expr e)
{
Value v;
eval(env, e, v);
if (v.type != tBool)
throw TypeError(format("value is %1% while a Boolean was expected") % showType(v));
return v.boolean;
}
void EvalState::strictEval(Env & env, Expr e, Value & v)
{
eval(env, e, v);
if (v.type == tAttrs) {
foreach (Bindings::iterator, i, *v.attrs)
forceValue(i->second);
}
else if (v.type == tList) {
for (unsigned int n = 0; n < v.list.length; ++n)
forceValue(v.list.elems[n]);
}
}
void EvalState::strictEval(Expr e, Value & v)
{
strictEval(baseEnv, e, v);
}
void EvalState::forceValue(Value & v)
{
if (v.type == tThunk) {
v.type = tBlackhole;
eval(*v.thunk.env, v.thunk.expr, v);
}
else if (v.type == tCopy) {
forceValue(*v.val);
v = *v.val;
}
else if (v.type == tBlackhole)
throw EvalError("infinite recursion encountered");
}
int EvalState::forceInt(Value & v)
{
forceValue(v);
if (v.type != tInt)
throw TypeError(format("value is %1% while an integer was expected") % showType(v));
return v.integer;
}
void EvalState::forceAttrs(Value & v)
{
forceValue(v);
if (v.type != tAttrs)
throw TypeError(format("value is %1% while an attribute set was expected") % showType(v));
}
void EvalState::forceList(Value & v)
{
forceValue(v);
if (v.type != tList)
throw TypeError(format("value is %1% while a list was expected") % showType(v));
}
bool EvalState::eqValues(Value & v1, Value & v2)
{
forceValue(v1);
forceValue(v2);
if (v1.type != v2.type) return false;
switch (v1.type) {
case tInt:
return v1.integer == v2.integer;
case tBool:
return v1.boolean == v2.boolean;
case tString:
/* !!! contexts */
return strcmp(v1.string.s, v2.string.s) == 0;
case tList:
if (v2.type != tList || v1.list.length != v2.list.length) return false;
for (unsigned int n = 0; n < v1.list.length; ++n)
if (!eqValues(v1.list.elems[n], v2.list.elems[n])) return false;
return true;
case tAttrs: {
if (v2.type != tAttrs || v1.attrs->size() != v2.attrs->size()) return false;
Bindings::iterator i, j;
for (i = v1.attrs->begin(), j = v2.attrs->begin(); i != v1.attrs->end(); ++i, ++j)
if (!eqValues(i->second, j->second)) return false;
return true;
}
default:
throw Error("cannot compare given values");
}
}
#if 0
/* Pattern-match `pat' against `arg'. The result is a set of
substitutions (`subs') and a set of recursive substitutions
(`subsRecursive'). The latter can refer to the variables bound by
@ -683,9 +1216,6 @@ LocalNoInline(bool areEqual(EvalState & state, Expr e1, Expr e2))
}
static char * deepestStack = (char *) -1; /* for measuring stack usage */
Expr evalExpr2(EvalState & state, Expr e)
{
/* When changing this function, make sure that you don't cause a
@ -884,23 +1414,19 @@ Expr strictEvalExpr(EvalState & state, Expr e)
ATermMap strictNormalForms;
return strictEvalExpr(state, e, strictNormalForms);
}
#endif
/* Yes, this is a really bad idea... */
extern "C" {
unsigned long AT_calcAllocatedSize();
}
void printEvalStats(EvalState & state)
{
char x;
bool showStats = getEnv("NIX_SHOW_STATS", "0") != "0";
printMsg(showStats ? lvlInfo : lvlDebug,
format("evaluated %1% expressions, %2% cache hits, %3%%% efficiency, used %4% ATerm bytes, used %5% bytes of stack space")
% state.nrEvaluated % state.nrCached
% ((float) state.nrCached / (float) state.nrEvaluated * 100)
% AT_calcAllocatedSize()
% (&x - deepestStack));
format("evaluated %1% expressions, used %2% bytes of stack space, allocated %3% values, allocated %4% environments")
% state.nrEvaluated
% (&x - deepestStack)
% state.nrValues
% state.nrEnvs);
if (showStats)
printATermMapStats();
}

152
src/libexpr/eval.hh
View file

@ -11,7 +11,101 @@ namespace nix {
class Hash;
class EvalState;
struct Env;
struct Value;
typedef ATerm Sym;
typedef std::map<Sym, Value> Bindings;
struct Env
{
Env * up;
Bindings bindings;
};
typedef enum {
tInt = 1,
tBool,
tString,
tPath,
tNull,
tAttrs,
tList,
tThunk,
tLambda,
tCopy,
tBlackhole,
tPrimOp,
tPrimOpApp,
} ValueType;
typedef void (* PrimOp) (EvalState & state, Value * * args, Value & v);
struct Value
{
ValueType type;
union
{
int integer;
bool boolean;
struct {
const char * s;
const char * * context;
} string;
Bindings * attrs;
struct {
unsigned int length;
Value * elems;
} list;
struct {
Env * env;
Expr expr;
} thunk;
struct {
Env * env;
Pattern pat;
Expr body;
} lambda;
Value * val;
struct {
PrimOp fun;
unsigned int arity;
} primOp;
struct {
Value * left, * right;
unsigned int argsLeft;
} primOpApp;
};
};
static inline void mkInt(Value & v, int n)
{
v.type = tInt;
v.integer = n;
}
static inline void mkBool(Value & v, bool b)
{
v.type = tBool;
v.boolean = b;
}
static inline void mkString(Value & v, const char * s)
{
v.type = tString;
v.string.s = s;
v.string.context = 0;
}
typedef std::map<Path, PathSet> DrvRoots;
typedef std::map<Path, Hash> DrvHashes;
@ -22,32 +116,69 @@ typedef std::map<Path, Path> SrcToStore;
struct EvalState;
/* Note: using a ATermVector is safe here, since when we call a primop
we also have an ATermList on the stack. */
typedef Expr (* PrimOp) (EvalState &, const ATermVector & args);
std::ostream & operator << (std::ostream & str, Value & v);
struct EvalState
{
ATermMap normalForms;
ATermMap primOps;
DrvRoots drvRoots;
DrvHashes drvHashes; /* normalised derivation hashes */
SrcToStore srcToStore;
unsigned int nrEvaluated;
unsigned int nrCached;
unsigned long nrValues;
unsigned long nrEnvs;
unsigned long nrEvaluated;
bool allowUnsafeEquality;
EvalState();
void addPrimOps();
/* Evaluate an expression to normal form, storing the result in
value `v'. */
void eval(Expr e, Value & v);
void eval(Env & env, Expr e, Value & v);
/* Evaluation the expression, then verify that it has the expected
type. */
bool evalBool(Env & env, Expr e);
/* Evaluate an expression, and recursively evaluate list elements
and attributes. */
void strictEval(Expr e, Value & v);
void strictEval(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. Otherwise, this is a no-op. */
void forceValue(Value & v);
/* Force `v', and then verify that it has the expected type. */
int forceInt(Value & v);
void forceAttrs(Value & v);
void forceList(Value & v);
private:
/* The base environment, containing the builtin functions and
values. */
Env & baseEnv;
void createBaseEnv();
void addPrimOp(const string & name,
unsigned int arity, PrimOp primOp);
/* Do a deep equality test between two values. That is, list
elements and attributes are compared recursively. */
bool eqValues(Value & v1, Value & v2);
/* Allocation primitives. */
Value * allocValues(unsigned int count);
Env & allocEnv();
};
#if 0
/* Evaluate an expression to normal form. */
Expr evalExpr(EvalState & state, Expr e);
@ -86,11 +217,12 @@ Path coerceToPath(EvalState & state, Expr e, PathSet & context);
value or has a binding in the `args' map. Note: result is a call,
not a normal form; it should be evaluated by calling evalExpr(). */
Expr autoCallFunction(Expr e, const ATermMap & args);
#endif
/* Print statistics. */
void printEvalStats(EvalState & state);
}

2
src/libexpr/get-drvs.cc
View file

@ -6,6 +6,7 @@
namespace nix {
#if 0
string DrvInfo::queryDrvPath(EvalState & state) const
{
if (drvPath == "") {
@ -256,6 +257,7 @@ void getDerivations(EvalState & state, Expr e, const string & pathPrefix,
Exprs doneExprs;
getDerivations(state, e, pathPrefix, autoArgs, drvs, doneExprs);
}
#endif
}

4
src/libexpr/parser.y
View file

@ -375,7 +375,7 @@ expr_op
| expr_op UPDATE expr_op { $$ = makeOpUpdate($1, $3); }
| expr_op '~' expr_op { $$ = makeSubPath($1, $3); }
| expr_op '?' ID { $$ = makeOpHasAttr($1, $3); }
| expr_op '+' expr_op { $$ = makeOpPlus($1, $3); }
| expr_op '+' expr_op { $$ = makeConcatStrings(ATmakeList2($1, $3)); }
| expr_op CONCAT expr_op { $$ = makeOpConcat($1, $3); }
| expr_app
;
@ -513,7 +513,7 @@ static Expr parse(EvalState & state,
if (res) throw ParseError(data.error);
try {
checkVarDefs(state.primOps, data.result);
// !!! checkVarDefs(state.primOps, data.result);
} catch (Error & e) {
throw ParseError(format("%1%, in `%2%'") % e.msg() % path);
}

58
src/libexpr/primops.cc
View file

@ -19,6 +19,7 @@
namespace nix {
#if 0
/*************************************************************
* Constants
*************************************************************/
@ -895,18 +896,21 @@ static Expr prim_isList(EvalState & state, const ATermVector & args)
ATermList list;
return makeBool(matchList(evalExpr(state, args[0]), list));
}
#endif
/* Return the first element of a list. */
static Expr prim_head(EvalState & state, const ATermVector & args)
static void prim_head(EvalState & state, Value * * args, Value & v)
{
ATermList list = evalList(state, args[0]);
if (ATisEmpty(list))
state.forceList(*args[0]);
if (args[0]->list.length == 0)
throw Error("`head' called on an empty list");
return evalExpr(state, ATgetFirst(list));
state.forceValue(args[0]->list.elems[0]);
v = args[0]->list.elems[0];
}
#if 0
/* Return a list consisting of everything but the the first element of
a list. */
static Expr prim_tail(EvalState & state, const ATermVector & args)
@ -938,6 +942,7 @@ static Expr prim_length(EvalState & state, const ATermVector & args)
ATermList list = evalList(state, args[0]);
return makeInt(ATgetLength(list));
}
#endif
/*************************************************************
@ -945,14 +950,13 @@ static Expr prim_length(EvalState & state, const ATermVector & args)
*************************************************************/
static Expr prim_add(EvalState & state, const ATermVector & args)
static void prim_add(EvalState & state, Value * * args, Value & v)
{
int i1 = evalInt(state, args[0]);
int i2 = evalInt(state, args[1]);
return makeInt(i1 + i2);
mkInt(v, state.forceInt(*args[0]) + state.forceInt(*args[1]));
}
#if 0
static Expr prim_sub(EvalState & state, const ATermVector & args)
{
int i1 = evalInt(state, args[0]);
@ -1102,6 +1106,7 @@ static Expr prim_compareVersions(EvalState & state, const ATermVector & args)
int d = compareVersions(version1, version2);
return makeInt(d);
}
#endif
/*************************************************************
@ -1109,14 +1114,31 @@ static Expr prim_compareVersions(EvalState & state, const ATermVector & args)
*************************************************************/
void EvalState::addPrimOps()
void EvalState::createBaseEnv()
{
addPrimOp("builtins", 0, prim_builtins);
baseEnv.up = 0;
{ Value & v = baseEnv.bindings[toATerm("builtins")];
v.type = tAttrs;
v.attrs = new Bindings;
}
/* Add global constants such as `true' to the base environment. */
{ Value & v = baseEnv.bindings[toATerm("true")];
mkBool(v, true);
}
{ Value & v = baseEnv.bindings[toATerm("false")];
mkBool(v, false);
}
{ Value & v = baseEnv.bindings[toATerm("null")];
v.type = tNull;
}
{ Value & v = (*baseEnv.bindings[toATerm("builtins")].attrs)[toATerm("currentSystem")];
mkString(v, thisSystem.c_str()); // !!! copy string
}
#if 0
// Constants
addPrimOp("true", 0, prim_true);
addPrimOp("false", 0, prim_false);
addPrimOp("null", 0, prim_null);
addPrimOp("__currentSystem", 0, prim_currentSystem);
addPrimOp("__currentTime", 0, prim_currentTime);
@ -1134,7 +1156,6 @@ void EvalState::addPrimOps()
addPrimOp("__tryEval", 1, prim_tryEval);
addPrimOp("__getEnv", 1, prim_getEnv);
addPrimOp("__trace", 2, prim_trace);
// Expr <-> String
addPrimOp("__exprToString", 1, prim_exprToString);
@ -1169,13 +1190,17 @@ void EvalState::addPrimOps()
// Lists
addPrimOp("__isList", 1, prim_isList);
#endif
addPrimOp("__head", 1, prim_head);
#if 0
addPrimOp("__tail", 1, prim_tail);
addPrimOp("map", 2, prim_map);
addPrimOp("__length", 1, prim_length);
#endif
// Integer arithmetic
addPrimOp("__add", 2, prim_add);
#if 0
addPrimOp("__sub", 2, prim_sub);
addPrimOp("__mul", 2, prim_mul);
addPrimOp("__div", 2, prim_div);
@ -1191,6 +1216,7 @@ void EvalState::addPrimOps()
// Versions
addPrimOp("__parseDrvName", 1, prim_parseDrvName);
addPrimOp("__compareVersions", 2, prim_compareVersions);
#endif
}

10
src/nix-instantiate/nix-instantiate.cc
View file

@ -37,6 +37,7 @@ static int rootNr = 0;
static bool indirectRoot = false;
#if 0
static void printResult(EvalState & state, Expr e,
bool evalOnly, bool xmlOutput, const ATermMap & autoArgs)
{
@ -63,21 +64,28 @@ static void printResult(EvalState & state, Expr e,
}
}
}
#endif
void processExpr(EvalState & state, const Strings & attrPaths,
bool parseOnly, bool strict, const ATermMap & autoArgs,
bool evalOnly, bool xmlOutput, Expr e)
{
Value v;
state.strictEval(e, v);
std::cout << v << std::endl;
#if 0
for (Strings::const_iterator i = attrPaths.begin(); i != attrPaths.end(); ++i) {
Expr e2 = findAlongAttrPath(state, *i, autoArgs, e);
if (!parseOnly)
if (strict)
e2 = strictEvalExpr(state, e2);
e2 = state.strictEval(e2);
else
e2 = evalExpr(state, e2);
printResult(state, e2, evalOnly, xmlOutput, autoArgs);
}
#endif
}