* Allow function argument default values to refer to other arguments
of the function. Implements NIX-45.
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310e605995
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@ -24,49 +24,54 @@ void EvalState::addPrimOp(const string & name,
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/* Substitute an argument set into the body of a function. */
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static Expr substArgs(Expr body, ATermList formals, Expr arg)
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{
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ATermMap subs(ATgetLength(formals) * 2);
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unsigned int nrFormals = ATgetLength(formals);
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ATermMap subs(nrFormals);
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/* ({x ? E1; y ? E2, z}: E3) {x = E4; z = E5;}
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=> let {x = E4; y = E2; z = E5; body = E3; }
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=> subst(E3, s)
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s = {
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R = rec {x = E4; y = E2; z = E5}
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x -> R.x
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y -> R.y
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z -> R.z
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}
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*/
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/* Get the formal arguments. */
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for (ATermIterator i(formals); i; ++i) {
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Expr name, def;
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if (matchNoDefFormal(*i, name))
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subs.set(name, makeUndefined());
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else if (matchDefFormal(*i, name, def))
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subs.set(name, def);
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else abort(); /* can't happen */
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}
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/* Get the actual arguments, and check that they match with the
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formals. */
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/* Get the actual arguments and put them in the substitution. */
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ATermMap args(128); /* !!! fix */
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queryAllAttrs(arg, args);
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for (ATermMap::const_iterator i = args.begin(); i != args.end(); ++i) {
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Expr cur = subs.get(i->key);
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if (!subs.get(i->key))
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throw Error(format("unexpected function argument `%1%'")
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% aterm2String(i->key));
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for (ATermMap::const_iterator i = args.begin(); i != args.end(); ++i)
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subs.set(i->key, i->value);
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/* Get the formal arguments. */
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ATermVector defsUsed;
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ATermList recAttrs = ATempty;
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for (ATermIterator i(formals); i; ++i) {
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Expr name, def = 0;
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if (!matchNoDefFormal(*i, name) && !matchDefFormal(*i, name, def))
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abort(); /* can't happen */
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if (subs[name] == 0) {
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if (def == 0) throw Error(format("required function argument `%1%' missing")
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% aterm2String(name));
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defsUsed.push_back(name);
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recAttrs = ATinsert(recAttrs, makeBind(name, def, makeNoPos()));
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}
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}
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/* Check that all arguments are defined. */
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for (ATermMap::const_iterator i = subs.begin(); i != subs.end(); ++i)
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if (i->value == makeUndefined())
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throw Error(format("required function argument `%1%' missing")
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% aterm2String(i->key));
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/* Make a recursive attribute set out of the (argument-name,
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value) tuples. This is so that we can support default
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parameters that refer to each other, e.g. ({x, y ? x + x}: y)
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{x = "foo";} evaluates to "foofoo". */
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if (defsUsed.size() != 0) {
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for (ATermMap::const_iterator i = args.begin(); i != args.end(); ++i)
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recAttrs = ATinsert(recAttrs, makeBind(i->key, i->value, makeNoPos()));
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Expr rec = makeRec(recAttrs, ATempty);
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for (ATermVector::iterator i = defsUsed.begin(); i != defsUsed.end(); ++i)
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subs.set(*i, makeSelect(rec, *i));
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}
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if (subs.size() != nrFormals) {
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/* One or more actual arguments were not declared as formal
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arguments. Find out which. */
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for (ATermIterator i(formals); i; ++i) {
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Expr name, def;
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matchNoDefFormal(*i, name) || matchDefFormal(*i, name, def);
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subs.remove(name);
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}
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throw Error(format("unexpected function argument `%1%'")
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% aterm2String(subs.begin()->key));
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}
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return substitute(Substitution(0, &subs), body);
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}
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@ -217,17 +217,17 @@ unsigned int ATermMap::size()
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void printATermMapStats()
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{
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cout << "RESIZES: " << nrResizes << " "
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cerr << "RESIZES: " << nrResizes << " "
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<< sizeTotalAlloc << " "
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<< sizeCurAlloc << " "
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<< sizeMaxAlloc << endl;
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cout << "SET: "
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cerr << "SET: "
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<< nrItemsSet << " "
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<< nrSetProbes << " "
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<< (double) nrSetProbes / nrItemsSet << endl;
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cout << "GET: "
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cerr << "GET: "
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<< nrItemsGet << " "
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<< nrGetProbes << " "
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<< (double) nrGetProbes / nrItemsGet << endl;
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@ -50,6 +50,11 @@ public:
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ATerm get(ATerm key) const;
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ATerm operator [](ATerm key) const
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{
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return get(key);
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}
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void remove(ATerm key);
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unsigned int size();
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1
tests/lang/eval-fail-missing-arg.nix
Normal file
1
tests/lang/eval-fail-missing-arg.nix
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@ -0,0 +1 @@
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({x, y, z}: x + y + z) {x = "foo"; z = "bar";}
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1
tests/lang/eval-fail-undeclared-arg.nix
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1
tests/lang/eval-fail-undeclared-arg.nix
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@ -0,0 +1 @@
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({x, z}: x + z) {x = "foo"; y = "bla"; z = "bar";}
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