forked from lix-project/lix
Simplify inherited attribute handling
This reduces the difference between inherited and non-inherited attribute handling to the choice of which env to use (in recs and lets) by setting the AttrDef::e to a new ExprVar in the parser rather than carrying a separate AttrDef::v VarRef member. As an added bonus, this allows inherited attributes that inherit from a with to delay forcing evaluation of the with's attributes. Signed-off-by: Shea Levy <shea@shealevy.com>
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@ -521,22 +521,16 @@ void ExprAttrs::eval(EvalState & state, Env & env, Value & v)
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environment, while the inherited attributes are evaluated
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in the original environment. */
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unsigned int displ = 0;
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foreach (AttrDefs::iterator, i, attrs)
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if (i->second.inherited) {
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/* !!! handle overrides? */
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Value * vAttr = state.lookupVar(&env, i->second.var);
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env2.values[displ++] = vAttr;
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v.attrs->push_back(Attr(i->first, vAttr, &i->second.pos));
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} else {
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Value * vAttr;
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if (hasOverrides) {
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vAttr = state.allocValue();
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mkThunk(*vAttr, env2, i->second.e);
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} else
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vAttr = i->second.e->maybeThunk(state, env2);
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env2.values[displ++] = vAttr;
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v.attrs->push_back(Attr(i->first, vAttr, &i->second.pos));
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}
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foreach (AttrDefs::iterator, i, attrs) {
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Value * vAttr;
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if (hasOverrides && !i->second.inherited) {
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vAttr = state.allocValue();
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mkThunk(*vAttr, env2, i->second.e);
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} else
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vAttr = i->second.e->maybeThunk(state, i->second.inherited ? env : env2);
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env2.values[displ++] = vAttr;
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v.attrs->push_back(Attr(i->first, vAttr, &i->second.pos));
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}
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/* If the rec contains an attribute called `__overrides', then
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evaluate it, and add the attributes in that set to the rec.
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@ -563,10 +557,7 @@ void ExprAttrs::eval(EvalState & state, Env & env, Value & v)
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else {
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foreach (AttrDefs::iterator, i, attrs)
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if (i->second.inherited)
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v.attrs->push_back(Attr(i->first, state.lookupVar(&env, i->second.var), &i->second.pos));
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else
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v.attrs->push_back(Attr(i->first, i->second.e->maybeThunk(state, env), &i->second.pos));
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v.attrs->push_back(Attr(i->first, i->second.e->maybeThunk(state, env), &i->second.pos));
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}
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}
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@ -583,10 +574,7 @@ void ExprLet::eval(EvalState & state, Env & env, Value & v)
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environment. */
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unsigned int displ = 0;
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foreach (ExprAttrs::AttrDefs::iterator, i, attrs->attrs)
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if (i->second.inherited)
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env2.values[displ++] = state.lookupVar(&env, i->second.var);
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else
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env2.values[displ++] = i->second.e->maybeThunk(state, env2);
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env2.values[displ++] = i->second.e->maybeThunk(state, i->second.inherited ? env : env2);
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body->eval(state, env2, v);
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}
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@ -602,7 +590,7 @@ void ExprList::eval(EvalState & state, Env & env, Value & v)
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void ExprVar::eval(EvalState & state, Env & env, Value & v)
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{
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Value * v2 = state.lookupVar(&env, info);
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Value * v2 = state.lookupVar(&env, info, false);
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state.forceValue(*v2);
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v = *v2;
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}
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@ -206,7 +206,7 @@ private:
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void addPrimOp(const string & name,
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unsigned int arity, PrimOpFun primOp);
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inline Value * lookupVar(Env * env, const VarRef & var, bool noEval = false);
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inline Value * lookupVar(Env * env, const VarRef & var, bool noEval);
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friend class ExprVar;
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friend class ExprAttrs;
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@ -230,14 +230,12 @@ void ExprAttrs::bindVars(const StaticEnv & env)
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newEnv.vars[i->first] = i->second.displ = displ++;
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foreach (AttrDefs::iterator, i, attrs)
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if (i->second.inherited) i->second.var.bind(env);
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else i->second.e->bindVars(newEnv);
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i->second.e->bindVars(i->second.inherited ? env : newEnv);
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}
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else
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foreach (AttrDefs::iterator, i, attrs)
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if (i->second.inherited) i->second.var.bind(env);
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else i->second.e->bindVars(env);
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i->second.e->bindVars(env);
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}
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void ExprList::bindVars(const StaticEnv & env)
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@ -274,8 +272,7 @@ void ExprLet::bindVars(const StaticEnv & env)
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newEnv.vars[i->first] = i->second.displ = displ++;
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foreach (ExprAttrs::AttrDefs::iterator, i, attrs->attrs)
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if (i->second.inherited) i->second.var.bind(env);
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else i->second.e->bindVars(newEnv);
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i->second.e->bindVars(i->second.inherited ? env : newEnv);
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body->bindVars(newEnv);
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}
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@ -159,12 +159,10 @@ struct ExprAttrs : Expr
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bool recursive;
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struct AttrDef {
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bool inherited;
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Expr * e; // if not inherited
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VarRef var; // if inherited
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Expr * e;
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Pos pos;
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unsigned int displ; // displacement
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AttrDef(Expr * e, const Pos & pos) : inherited(false), e(e), pos(pos) { };
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AttrDef(const Symbol & name, const Pos & pos) : inherited(true), var(name), pos(pos) { };
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AttrDef(Expr * e, const Pos & pos, bool inherited=false) : inherited(inherited), e(e), pos(pos) { };
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AttrDef() { };
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};
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typedef std::map<Symbol, AttrDef> AttrDefs;
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@ -413,7 +413,7 @@ binds
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if ($$->attrs.find(*i) != $$->attrs.end())
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dupAttr(*i, makeCurPos(@3, data), $$->attrs[*i].pos);
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Pos pos = makeCurPos(@3, data);
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$$->attrs[*i] = ExprAttrs::AttrDef(*i, pos);
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$$->attrs[*i] = ExprAttrs::AttrDef(new ExprVar(*i), pos, true);
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}
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}
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| binds INHERIT '(' expr ')' attrs ';'
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1
tests/lang/eval-okay-delayed-with-inherit.exp
Normal file
1
tests/lang/eval-okay-delayed-with-inherit.exp
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@ -0,0 +1 @@
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"b-overridden"
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24
tests/lang/eval-okay-delayed-with-inherit.nix
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24
tests/lang/eval-okay-delayed-with-inherit.nix
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@ -0,0 +1,24 @@
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let
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pkgs_ = with pkgs; {
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a = derivation {
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name = "a";
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system = builtins.currentSystem;
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builder = "/bin/sh";
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args = [ "-c" "touch $out" ];
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inherit b;
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};
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inherit b;
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};
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packageOverrides = p: {
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b = derivation {
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name = "b-overridden";
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system = builtins.currentSystem;
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builder = "/bin/sh";
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args = [ "-c" "touch $out" ];
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};
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};
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pkgs = pkgs_ // (packageOverrides pkgs_);
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in pkgs.a.b.name
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