lix/src/libexpr/eval.cc
Eelco Dolstra 9985230c00 * After parsing, compute level/displacement pairs for each variable
use site, allowing environments to be stores as vectors of values
  rather than maps.  This should speed up evaluation and reduce the
  number of allocations.
2010-04-14 14:42:32 +00:00

1064 lines
28 KiB
C++

#include "eval.hh"
#include "parser.hh"
#include "hash.hh"
#include "util.hh"
#include "store-api.hh"
#include "derivations.hh"
#include "globals.hh"
#include <cstring>
#define LocalNoInline(f) static f __attribute__((noinline)); f
#define LocalNoInlineNoReturn(f) static f __attribute__((noinline, noreturn)); f
namespace nix {
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 << "\"";
for (const char * i = v.string.s; *i; i++)
if (*i == '\"' || *i == '\\') str << "\\" << *i;
else if (*i == '\n') str << "\\n";
else if (*i == '\r') str << "\\r";
else if (*i == '\t') str << "\\t";
else str << *i;
str << "\"";
break;
case tPath:
str << v.path; // !!! escaping?
break;
case tNull:
str << "true";
break;
case tAttrs:
str << "{ ";
foreach (Bindings::iterator, i, *v.attrs)
str << (string) 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:
case tCopy:
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 tInt: return "an integer";
case tBool: return "a boolean";
case tString: return "a string";
case tPath: return "a path";
case tAttrs: return "an attribute set";
case tList: return "a list";
case tNull: return "null";
case tLambda: return "a function";
case tPrimOp: return "a built-in function";
case tPrimOpApp: return "a partially applied built-in function";
default: throw Error(format("unknown type: %1%") % v.type);
}
}
EvalState::EvalState()
: sWith(symbols.create("<with>"))
, sOutPath(symbols.create("outPath"))
, sDrvPath(symbols.create("drvPath"))
, sType(symbols.create("type"))
, sMeta(symbols.create("meta"))
, sName(symbols.create("name"))
, baseEnv(allocEnv(128))
{
nrValues = nrEnvs = nrEvaluated = recursionDepth = maxRecursionDepth = 0;
deepestStack = (char *) -1;
createBaseEnv();
allowUnsafeEquality = getEnv("NIX_NO_UNSAFE_EQ", "") == "";
}
EvalState::~EvalState()
{
assert(recursionDepth == 0);
}
void EvalState::addConstant(const string & name, Value & v)
{
#if 0
baseEnv.bindings[symbols.create(name)] = v;
string name2 = string(name, 0, 2) == "__" ? string(name, 2) : name;
(*baseEnv.bindings[symbols.create("builtins")].attrs)[symbols.create(name2)] = v;
nrValues += 2;
#endif
}
void EvalState::addPrimOp(const string & name,
unsigned int arity, PrimOp primOp)
{
#if 0
Value v;
v.type = tPrimOp;
v.primOp.arity = arity;
v.primOp.fun = primOp;
baseEnv.bindings[symbols.create(name)] = v;
string name2 = string(name, 0, 2) == "__" ? string(name, 2) : name;
(*baseEnv.bindings[symbols.create("builtins")].attrs)[symbols.create(name2)] = v;
nrValues += 2;
#endif
}
/* Every "format" object (even temporary) takes up a few hundred bytes
of stack space, which is a real killer in the recursive
evaluator. So here are some helper functions for throwing
exceptions. */
LocalNoInlineNoReturn(void throwEvalError(const char * s))
{
throw EvalError(s);
}
LocalNoInlineNoReturn(void throwEvalError(const char * s, const string & s2))
{
throw EvalError(format(s) % s2);
}
LocalNoInlineNoReturn(void throwEvalError(const char * s, const string & s2, const string & s3))
{
throw EvalError(format(s) % s2 % s3);
}
LocalNoInlineNoReturn(void throwTypeError(const char * s))
{
throw TypeError(s);
}
LocalNoInlineNoReturn(void throwTypeError(const char * s, const string & s2))
{
throw TypeError(format(s) % s2);
}
LocalNoInlineNoReturn(void throwTypeError(const char * s, const Pos & pos, const string & s2))
{
throw TypeError(format(s) % pos % s2);
}
LocalNoInlineNoReturn(void throwTypeError(const char * s, const Pos & pos))
{
throw TypeError(format(s) % pos);
}
LocalNoInlineNoReturn(void throwAssertionError(const char * s, const Pos & pos))
{
throw AssertionError(format(s) % pos);
}
LocalNoInline(void addErrorPrefix(Error & e, const char * s))
{
e.addPrefix(s);
}
LocalNoInline(void addErrorPrefix(Error & e, const char * s, const string & s2))
{
e.addPrefix(format(s) % s2);
}
LocalNoInline(void addErrorPrefix(Error & e, const char * s, const Pos & pos))
{
e.addPrefix(format(s) % pos);
}
LocalNoInline(void addErrorPrefix(Error & e, const char * s, const string & s2, const string & s3))
{
e.addPrefix(format(s) % s2 % s3);
}
void mkString(Value & v, const char * s)
{
v.type = tString;
v.string.s = strdup(s);
v.string.context = 0;
}
void mkString(Value & v, const string & s, const PathSet & context)
{
mkString(v, s.c_str());
if (!context.empty()) {
unsigned int n = 0;
v.string.context = new const char *[context.size() + 1];
foreach (PathSet::const_iterator, i, context)
v.string.context[n++] = strdup(i->c_str());
v.string.context[n] = 0;
}
}
void mkPath(Value & v, const char * s)
{
v.type = tPath;
v.path = strdup(s);
}
Value * EvalState::lookupVar(Env * env, const Symbol & name)
{
#if 0
/* First look for a regular variable binding for `name'. */
Bindings::iterator i = env2->bindings.find(name);
if (i != env2->bindings.end()) return &i->second;
}
/* Otherwise, look for a `with' attribute set containing `name'.
Inner `withs' take precedence (i.e. `with {x=1;}; with {x=2;};
x' evaluates to 2). */
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;
}
throwEvalError("urgh! undefined variable `%1%'", name);
#endif
}
Value * EvalState::allocValues(unsigned int count)
{
nrValues += count;
return new Value[count]; // !!! check destructor
}
Env & EvalState::allocEnv(unsigned int size)
{
nrEnvs++;
Env * env = (Env *) malloc(sizeof(Env) + size * sizeof(Value));
return *env;
}
void EvalState::mkList(Value & v, unsigned int length)
{
v.type = tList;
v.list.length = length;
v.list.elems = allocValues(length);
}
void EvalState::mkAttrs(Value & v)
{
v.type = tAttrs;
v.attrs = new Bindings;
}
void EvalState::mkThunk_(Value & v, Expr * expr)
{
mkThunk(v, baseEnv, expr);
}
void EvalState::cloneAttrs(Value & src, Value & dst)
{
mkAttrs(dst);
foreach (Bindings::iterator, i, *src.attrs)
mkCopy((*dst.attrs)[i->first], i->second);
}
void EvalState::evalFile(const Path & path, Value & v)
{
startNest(nest, lvlTalkative, format("evaluating file `%1%'") % path);
Expr * e = parseTrees[path];
if (!e) {
e = parseExprFromFile(*this, path);
parseTrees[path] = e;
}
try {
eval(e, v);
} catch (Error & e) {
addErrorPrefix(e, "while evaluating the file `%1%':\n", path);
throw;
}
}
struct RecursionCounter
{
EvalState & state;
RecursionCounter(EvalState & state) : state(state)
{
state.recursionDepth++;
if (state.recursionDepth > state.maxRecursionDepth)
state.maxRecursionDepth = state.recursionDepth;
}
~RecursionCounter()
{
state.recursionDepth--;
}
};
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! */
/* !!! Disable this eventually. */
RecursionCounter r(*this);
char x;
if (&x < deepestStack) deepestStack = &x;
debug(format("eval: %1%") % *e);
checkInterrupt();
nrEvaluated++;
e->eval(*this, env, v);
}
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)
throwTypeError("value is %1% while a Boolean was expected", showType(v));
return v.boolean;
}
void Expr::eval(EvalState & state, Env & env, Value & v)
{
abort();
}
void ExprInt::eval(EvalState & state, Env & env, Value & v)
{
mkInt(v, n);
}
void ExprString::eval(EvalState & state, Env & env, Value & v)
{
mkString(v, s.c_str());
}
void ExprPath::eval(EvalState & state, Env & env, Value & v)
{
mkPath(v, s.c_str());
}
void ExprAttrs::eval(EvalState & state, Env & env, Value & v)
{
if (recursive) {
/* Create a new environment that contains the attributes in
this `rec'. */
Env & env2(state.allocEnv(attrs.size() + inherited.size()));
env2.up = &env;
v.type = tAttrs;
v.attrs = new Bindings;
unsigned int displ = 0;
/* The recursive attributes are evaluated in the new
environment. */
foreach (Attrs::iterator, i, attrs) {
Value & v2 = (*v.attrs)[i->first];
mkCopy(v2, env2.values[displ]);
mkThunk(env2.values[displ++], env2, i->second);
}
#if 0
/* The inherited attributes, on the other hand, are
evaluated in the original environment. */
foreach (list<Symbol>::iterator, i, inherited) {
Value & v2 = env2.bindings[*i];
mkCopy(v2, *state.lookupVar(&env, *i));
}
#endif
}
else {
state.mkAttrs(v);
foreach (Attrs::iterator, i, attrs) {
Value & v2 = (*v.attrs)[i->first];
mkThunk(v2, env, i->second);
}
foreach (list<Symbol>::iterator, i, inherited) {
Value & v2 = (*v.attrs)[*i];
mkCopy(v2, *state.lookupVar(&env, *i));
}
}
}
void ExprLet::eval(EvalState & state, Env & env, Value & v)
{
/* Create a new environment that contains the attributes in this
`let'. */
Env & env2(state.allocEnv(attrs->attrs.size() + attrs->inherited.size()));
env2.up = &env;
unsigned int displ = 0;
/* The recursive attributes are evaluated in the new
environment. */
foreach (ExprAttrs::Attrs::iterator, i, attrs->attrs)
mkThunk(env2.values[displ++], env2, i->second);
#if 0
/* The inherited attributes, on the other hand, are evaluated in
the original environment. */
foreach (list<Symbol>::iterator, i, attrs->inherited) {
Value & v2 = env2.bindings[*i];
mkCopy(v2, *state.lookupVar(&env, *i));
}
#endif
state.eval(env2, body, v);
}
void ExprList::eval(EvalState & state, Env & env, Value & v)
{
state.mkList(v, elems.size());
for (unsigned int n = 0; n < v.list.length; ++n)
mkThunk(v.list.elems[n], env, elems[n]);
}
void ExprVar::eval(EvalState & state, Env & env, Value & v)
{
printMsg(lvlError, format("eval var %1% %2% %3%") % fromWith % level % displ);
if (fromWith) {
abort();
} else {
Env * env2 = &env;
for (unsigned int l = level; l; --l, env2 = env2->up) ;
state.forceValue(env2->values[displ]);
v = env2->values[displ];
}
}
void ExprSelect::eval(EvalState & state, Env & env, Value & v)
{
Value v2;
state.eval(env, e, v2);
state.forceAttrs(v2); // !!! eval followed by force is slightly inefficient
Bindings::iterator i = v2.attrs->find(name);
if (i == v2.attrs->end())
throwEvalError("attribute `%1%' missing", name);
try {
state.forceValue(i->second);
} catch (Error & e) {
addErrorPrefix(e, "while evaluating the attribute `%1%':\n", name);
throw;
}
v = i->second;
}
void ExprOpHasAttr::eval(EvalState & state, Env & env, Value & v)
{
Value vAttrs;
state.eval(env, e, vAttrs);
state.forceAttrs(vAttrs);
mkBool(v, vAttrs.attrs->find(name) != vAttrs.attrs->end());
}
void ExprLambda::eval(EvalState & state, Env & env, Value & v)
{
v.type = tLambda;
v.lambda.env = &env;
v.lambda.fun = this;
}
void ExprApp::eval(EvalState & state, Env & env, Value & v)
{
Value vFun;
state.eval(env, e1, vFun);
Value vArg;
mkThunk(vArg, env, e2); // !!! should this be on the heap?
state.callFunction(vFun, vArg, v);
}
void EvalState::callFunction(Value & fun, Value & arg, Value & v)
{
if (fun.type == tPrimOp || fun.type == tPrimOpApp) {
unsigned int argsLeft =
fun.type == tPrimOp ? fun.primOp.arity : fun.primOpApp.argsLeft;
if (argsLeft == 1) {
/* We have all the arguments, so call the primop. First
find the primop. */
Value * primOp = &fun;
while (primOp->type == tPrimOpApp) primOp = primOp->primOpApp.left;
assert(primOp->type == tPrimOp);
unsigned int arity = primOp->primOp.arity;
/* Put all the arguments in an array. */
Value * vArgs[arity];
unsigned int n = arity - 1;
vArgs[n--] = &arg;
for (Value * arg = &fun; 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] = fun;
v2[1] = arg;
v.type = tPrimOpApp;
v.primOpApp.left = &v2[0];
v.primOpApp.right = &v2[1];
v.primOpApp.argsLeft = argsLeft - 1;
}
return;
}
if (fun.type != tLambda)
throwTypeError("attempt to call something which is neither a function nor a primop (built-in operation) but %1%",
showType(fun));
unsigned int size =
(fun.lambda.fun->arg.empty() ? 0 : 1) +
(fun.lambda.fun->matchAttrs ? fun.lambda.fun->formals->formals.size() : 0);
Env & env2(allocEnv(size));
env2.up = fun.lambda.env;
unsigned int displ = 0;
if (!fun.lambda.fun->matchAttrs)
env2.values[displ++] = arg;
else {
forceAttrs(arg);
if (!fun.lambda.fun->arg.empty())
env2.values[displ++] = arg;
/* 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;
foreach (Formals::Formals_::iterator, i, fun.lambda.fun->formals->formals) {
Bindings::iterator j = arg.attrs->find(i->name);
if (j == arg.attrs->end()) {
if (!i->def) throwTypeError("function at %1% called without required argument `%2%'",
fun.lambda.fun->pos, i->name);
mkThunk(env2.values[displ++], env2, i->def);
} else {
attrsUsed++;
mkCopy(env2.values[displ++], 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 (!fun.lambda.fun->formals->ellipsis && attrsUsed != arg.attrs->size())
throwTypeError("function at %1% called with unexpected argument", fun.lambda.fun->pos);
}
try {
eval(env2, fun.lambda.fun->body, v);
} catch (Error & e) {
addErrorPrefix(e, "while evaluating the function at %1%:\n", fun.lambda.fun->pos);
throw;
}
}
void EvalState::autoCallFunction(const Bindings & args, Value & fun, Value & res)
{
forceValue(fun);
if (fun.type != tLambda || !fun.lambda.fun->matchAttrs) {
res = fun;
return;
}
Value actualArgs;
mkAttrs(actualArgs);
foreach (Formals::Formals_::iterator, i, fun.lambda.fun->formals->formals) {
Bindings::const_iterator j = args.find(i->name);
if (j != args.end())
(*actualArgs.attrs)[i->name] = j->second;
else if (!i->def)
throwTypeError("cannot auto-call a function that has an argument without a default value (`%1%')", i->name);
}
callFunction(fun, actualArgs, res);
}
void ExprWith::eval(EvalState & state, Env & env, Value & v)
{
abort();
#if 0
Env & env2(state.allocEnv());
env2.up = &env;
Value & vAttrs = env2.bindings[state.sWith];
state.eval(env, attrs, vAttrs);
state.forceAttrs(vAttrs);
state.eval(env2, body, v);
#endif
}
void ExprIf::eval(EvalState & state, Env & env, Value & v)
{
state.eval(env, state.evalBool(env, cond) ? then : else_, v);
}
void ExprAssert::eval(EvalState & state, Env & env, Value & v)
{
if (!state.evalBool(env, cond))
throwAssertionError("assertion failed at %1%", pos);
state.eval(env, body, v);
}
void ExprOpNot::eval(EvalState & state, Env & env, Value & v)
{
mkBool(v, !state.evalBool(env, e));
}
void ExprOpEq::eval(EvalState & state, Env & env, Value & v)
{
Value v1; state.eval(env, e1, v1);
Value v2; state.eval(env, e2, v2);
mkBool(v, state.eqValues(v1, v2));
}
void ExprOpNEq::eval(EvalState & state, Env & env, Value & v)
{
Value v1; state.eval(env, e1, v1);
Value v2; state.eval(env, e2, v2);
mkBool(v, !state.eqValues(v1, v2));
}
void ExprOpAnd::eval(EvalState & state, Env & env, Value & v)
{
mkBool(v, state.evalBool(env, e1) && state.evalBool(env, e2));
}
void ExprOpOr::eval(EvalState & state, Env & env, Value & v)
{
mkBool(v, state.evalBool(env, e1) || state.evalBool(env, e2));
}
void ExprOpImpl::eval(EvalState & state, Env & env, Value & v)
{
mkBool(v, !state.evalBool(env, e1) || state.evalBool(env, e2));
}
void ExprOpUpdate::eval(EvalState & state, Env & env, Value & v)
{
Value v2;
state.eval(env, e1, v2);
state.forceAttrs(v2);
state.cloneAttrs(v2, v);
state.eval(env, e2, v2);
state.forceAttrs(v2);
foreach (Bindings::iterator, i, *v2.attrs)
(*v.attrs)[i->first] = i->second; // !!! sharing
}
void ExprOpConcatLists::eval(EvalState & state, Env & env, Value & v)
{
Value v1; state.eval(env, e1, v1);
state.forceList(v1);
Value v2; state.eval(env, e2, v2);
state.forceList(v2);
state.mkList(v, v1.list.length + v2.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];
}
void ExprConcatStrings::eval(EvalState & state, Env & env, Value & v)
{
PathSet context;
std::ostringstream s;
bool first = true, isPath = false;
Value vStr;
foreach (vector<Expr *>::iterator, i, *es) {
state.eval(env, *i, vStr);
/* If the first element is a path, then the result will also
be a path, we don't copy anything (yet - that's done later,
since paths are copied when they are used in a derivation),
and none of the strings are allowed to have contexts. */
if (first) {
isPath = vStr.type == tPath;
first = false;
}
s << state.coerceToString(vStr, context, false, !isPath);
}
if (isPath && !context.empty())
throwEvalError("a string that refers to a store path cannot be appended to a path, in `%1%'", s.str());
if (isPath)
mkPath(v, s.str().c_str());
else
mkString(v, s.str(), context);
}
void EvalState::forceValue(Value & v)
{
if (v.type == tThunk) {
ValueType saved = v.type;
try {
v.type = tBlackhole;
eval(*v.thunk.env, v.thunk.expr, v);
} catch (Error & e) {
v.type = saved;
throw;
}
}
else if (v.type == tCopy) {
forceValue(*v.val);
v = *v.val;
}
else if (v.type == tApp)
callFunction(*v.app.left, *v.app.right, v);
else if (v.type == tBlackhole)
throwEvalError("infinite recursion encountered");
}
void EvalState::strictForceValue(Value & v)
{
forceValue(v);
if (v.type == tAttrs) {
foreach (Bindings::iterator, i, *v.attrs)
strictForceValue(i->second);
}
else if (v.type == tList) {
for (unsigned int n = 0; n < v.list.length; ++n)
strictForceValue(v.list.elems[n]);
}
}
int EvalState::forceInt(Value & v)
{
forceValue(v);
if (v.type != tInt)
throwTypeError("value is %1% while an integer was expected", showType(v));
return v.integer;
}
bool EvalState::forceBool(Value & v)
{
forceValue(v);
if (v.type != tBool)
throwTypeError("value is %1% while a Boolean was expected", showType(v));
return v.boolean;
}
void EvalState::forceAttrs(Value & v)
{
forceValue(v);
if (v.type != tAttrs)
throwTypeError("value is %1% while an attribute set was expected", showType(v));
}
void EvalState::forceList(Value & v)
{
forceValue(v);
if (v.type != tList)
throwTypeError("value is %1% while a list was expected", showType(v));
}
void EvalState::forceFunction(Value & v)
{
forceValue(v);
if (v.type != tLambda && v.type != tPrimOp && v.type != tPrimOpApp)
throwTypeError("value is %1% while a function was expected", showType(v));
}
string EvalState::forceString(Value & v)
{
forceValue(v);
if (v.type != tString)
throwTypeError("value is %1% while a string was expected", showType(v));
return string(v.string.s);
}
string EvalState::forceString(Value & v, PathSet & context)
{
string s = forceString(v);
if (v.string.context)
for (const char * * p = v.string.context; *p; ++p)
context.insert(*p);
return s;
}
string EvalState::forceStringNoCtx(Value & v)
{
string s = forceString(v);
if (v.string.context)
throwEvalError("the string `%1%' is not allowed to refer to a store path (such as `%2%')",
v.string.s, v.string.context[0]);
return s;
}
bool EvalState::isDerivation(Value & v)
{
if (v.type != tAttrs) return false;
Bindings::iterator i = v.attrs->find(sType);
return i != v.attrs->end() && forceStringNoCtx(i->second) == "derivation";
}
string EvalState::coerceToString(Value & v, PathSet & context,
bool coerceMore, bool copyToStore)
{
forceValue(v);
string s;
if (v.type == tString) {
if (v.string.context)
for (const char * * p = v.string.context; *p; ++p)
context.insert(*p);
return v.string.s;
}
if (v.type == tPath) {
Path path(canonPath(v.path));
if (!copyToStore) return path;
if (nix::isDerivation(path))
throwEvalError("file names are not allowed to end in `%1%'", drvExtension);
Path dstPath;
if (srcToStore[path] != "")
dstPath = srcToStore[path];
else {
dstPath = readOnlyMode
? computeStorePathForPath(path).first
: store->addToStore(path);
srcToStore[path] = dstPath;
printMsg(lvlChatty, format("copied source `%1%' -> `%2%'")
% path % dstPath);
}
context.insert(dstPath);
return dstPath;
}
if (v.type == tAttrs) {
Bindings::iterator i = v.attrs->find(sOutPath);
if (i == v.attrs->end())
throwTypeError("cannot coerce an attribute set (except a derivation) to a string");
return coerceToString(i->second, context, coerceMore, copyToStore);
}
if (coerceMore) {
/* Note that `false' is represented as an empty string for
shell scripting convenience, just like `null'. */
if (v.type == tBool && v.boolean) return "1";
if (v.type == tBool && !v.boolean) return "";
if (v.type == tInt) return int2String(v.integer);
if (v.type == tNull) return "";
if (v.type == tList) {
string result;
for (unsigned int n = 0; n < v.list.length; ++n) {
result += coerceToString(v.list.elems[n],
context, coerceMore, copyToStore);
if (n < v.list.length - 1
/* !!! not quite correct */
&& (v.list.elems[n].type != tList || v.list.elems[n].list.length != 0))
result += " ";
}
return result;
}
}
throwTypeError("cannot coerce %1% to a string", showType(v));
}
Path EvalState::coerceToPath(Value & v, PathSet & context)
{
string path = coerceToString(v, context, false, false);
if (path == "" || path[0] != '/')
throwEvalError("string `%1%' doesn't represent an absolute path", path);
return path;
}
bool EvalState::eqValues(Value & v1, Value & v2)
{
forceValue(v1);
forceValue(v2);
/* !!! Hack to support some old broken code that relies on pointer
equality tests between attribute sets. (Specifically,
builderDefs calls uniqList on a list of attribute sets.) Will
remove this eventually. */
if (&v1 == &v2) return true;
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 tPath:
return strcmp(v1.path, v2.path) == 0;
case tNull:
return true;
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;
}
/* Functions are incomparable. */
case tLambda:
case tPrimOp:
case tPrimOpApp:
return false;
default:
throwEvalError("cannot compare %1% with %2%", showType(v1), showType(v2));
}
}
void EvalState::printStats()
{
char x;
bool showStats = getEnv("NIX_SHOW_STATS", "0") != "0";
Verbosity v = showStats ? lvlInfo : lvlDebug;
printMsg(v, "evaluation statistics:");
printMsg(v, format(" expressions evaluated: %1%") % nrEvaluated);
printMsg(v, format(" stack space used: %1% bytes") % (&x - deepestStack));
printMsg(v, format(" max eval() nesting depth: %1%") % maxRecursionDepth);
printMsg(v, format(" stack space per eval() level: %1% bytes") % ((&x - deepestStack) / (float) maxRecursionDepth));
printMsg(v, format(" values allocated: %1%") % nrValues);
printMsg(v, format(" environments allocated: %1%") % nrEnvs);
printMsg(v, format(" symbols in symbol table: %1%") % symbols.size());
}
}