90b5e69284
This is requires if you have attribute names with dots in them. So you can now say: $ nix-instantiate '<nixos>' -A 'config.systemd.units."postgresql.service".text' --eval-only Fixes #151.
97 lines
2.7 KiB
C++
97 lines
2.7 KiB
C++
#include "attr-path.hh"
|
|
#include "eval-inline.hh"
|
|
#include "util.hh"
|
|
|
|
|
|
namespace nix {
|
|
|
|
|
|
static Strings parseAttrPath(const string & s)
|
|
{
|
|
Strings res;
|
|
string cur;
|
|
string::const_iterator i = s.begin();
|
|
while (i != s.end()) {
|
|
if (*i == '.') {
|
|
res.push_back(cur);
|
|
cur.clear();
|
|
} else if (*i == '"') {
|
|
++i;
|
|
while (1) {
|
|
if (i == s.end())
|
|
throw Error(format("missing closing quote in selection path `%1%'") % s);
|
|
if (*i == '"') break;
|
|
cur.push_back(*i++);
|
|
}
|
|
} else
|
|
cur.push_back(*i);
|
|
++i;
|
|
}
|
|
if (!cur.empty()) res.push_back(cur);
|
|
return res;
|
|
}
|
|
|
|
|
|
Value * findAlongAttrPath(EvalState & state, const string & attrPath,
|
|
Bindings & autoArgs, Value & vIn)
|
|
{
|
|
Strings tokens = parseAttrPath(attrPath);
|
|
|
|
Error attrError =
|
|
Error(format("attribute selection path `%1%' does not match expression") % attrPath);
|
|
|
|
Value * v = &vIn;
|
|
|
|
foreach (Strings::iterator, i, tokens) {
|
|
|
|
/* Is *i an index (integer) or a normal attribute name? */
|
|
enum { apAttr, apIndex } apType = apAttr;
|
|
string attr = *i;
|
|
unsigned int attrIndex;
|
|
if (string2Int(attr, attrIndex)) apType = apIndex;
|
|
|
|
/* Evaluate the expression. */
|
|
Value * vNew = state.allocValue();
|
|
state.autoCallFunction(autoArgs, *v, *vNew);
|
|
v = vNew;
|
|
state.forceValue(*v);
|
|
|
|
/* It should evaluate to either a set or an expression,
|
|
according to what is specified in the attrPath. */
|
|
|
|
if (apType == apAttr) {
|
|
|
|
if (v->type != tAttrs)
|
|
throw TypeError(
|
|
format("the expression selected by the selection path `%1%' should be a set but is %2%")
|
|
% attrPath % showType(*v));
|
|
|
|
if (attr.empty())
|
|
throw Error(format("empty attribute name in selection path `%1%'") % attrPath);
|
|
|
|
Bindings::iterator a = v->attrs->find(state.symbols.create(attr));
|
|
if (a == v->attrs->end())
|
|
throw Error(format("attribute `%1%' in selection path `%2%' not found") % attr % attrPath);
|
|
v = &*a->value;
|
|
}
|
|
|
|
else if (apType == apIndex) {
|
|
|
|
if (v->type != tList)
|
|
throw TypeError(
|
|
format("the expression selected by the selection path `%1%' should be a list but is %2%")
|
|
% attrPath % showType(*v));
|
|
|
|
if (attrIndex >= v->list.length)
|
|
throw Error(format("list index %1% in selection path `%2%' is out of range") % attrIndex % attrPath);
|
|
|
|
v = v->list.elems[attrIndex];
|
|
}
|
|
|
|
}
|
|
|
|
return v;
|
|
}
|
|
|
|
|
|
}
|