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primop functions listToAttrs (+test), __isAttrs, __trace added

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new configuration style proposal in lib/default-unstable.nix
This commit is contained in:
Marc Weber 2007-08-18 22:12:00 +00:00
parent dbc0170ed9
commit 2629998e91
3 changed files with 62 additions and 0 deletions
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53
src/libexpr/primops.cc
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@ -296,6 +296,17 @@ static Expr prim_getEnv(EvalState & state, const ATermVector & args)
return makeStr(getEnv(name));
}
/* for debugging purposes. print the first arg on stdout (perhaps stderr should be used?)
* and return the second
*/
static Expr prim_trace(EvalState & state, const ATermVector & args)
{
//string str = evalStringNoCtx(state, args[0]);
Expr a = evalExpr(state, args[0]);
printf("traced value: %s\n", atPrint(a).c_str());
return evalExpr(state, args[1]);
}
static Expr prim_relativise(EvalState & state, const ATermVector & args)
{
@ -744,6 +755,39 @@ static Expr prim_hasAttr(EvalState & state, const ATermVector & args)
}
/* takes
* param: list of { attr="attr"; value=value }
* returns an attribute set
* */
static Expr prim_listToAttrs(EvalState & state, const ATermVector & args)
{
try {
ATermMap res = ATermMap();
ATermList list;
list = evalList(state, args[0]);
for (ATermIterator i(list); i; ++i){
// *i should now contain a pointer to the list item expression
ATermList attrs;
Expr evaledExpr = evalExpr(state, *i);
if (matchAttrs(evaledExpr, attrs)){
Expr e = evalExpr(state, makeSelect(evaledExpr, toATerm("attr")));
string attr = evalStringNoCtx(state,e);
ATerm value;
Expr r = makeSelect(evaledExpr, toATerm("value"));
res.set(toATerm(attr), makeAttrRHS(r, makeNoPos()));
}
else {
throw EvalError(format("passed list item is a %s (value: %s). Set { attr=\"name\"; value=nix expr; } expected.") % showType(evaledExpr) % showValue(evaledExpr));
}
} // for
return makeAttrs(res);
} catch (Error & e) {
e.addPrefix(format("while calling listToAttrs "));
throw;
}
}
static Expr prim_removeAttrs(EvalState & state, const ATermVector & args)
{
ATermMap attrs;
@ -758,6 +802,12 @@ static Expr prim_removeAttrs(EvalState & state, const ATermVector & args)
return makeAttrs(attrs);
}
/* Determine whether the argument is a list. */
static Expr prim_isAttrs(EvalState & state, const ATermVector & args)
{
ATermList list;
return makeBool(matchAttrs(evalExpr(state, args[0]), list));
}
/*************************************************************
* Lists
@ -901,6 +951,7 @@ void EvalState::addPrimOps()
addPrimOp("abort", 1, prim_abort);
addPrimOp("throw", 1, prim_throw);
addPrimOp("__getEnv", 1, prim_getEnv);
addPrimOp("__trace", 2, prim_trace);
addPrimOp("relativise", 2, prim_relativise);
@ -923,7 +974,9 @@ void EvalState::addPrimOps()
addPrimOp("__attrNames", 1, prim_attrNames);
addPrimOp("__getAttr", 2, prim_getAttr);
addPrimOp("__hasAttr", 2, prim_hasAttr);
addPrimOp("__isAttrs", 1, prim_isAttrs);
addPrimOp("removeAttrs", 2, prim_removeAttrs);
addPrimOp("__listToAttrs", 1, prim_listToAttrs);
// Lists
addPrimOp("__isList", 1, prim_isList);