From aa0e2a2e70a3519a9dcb9b1da000a13c01aa6cc1 Mon Sep 17 00:00:00 2001 From: Eelco Dolstra Date: Thu, 29 Nov 2018 16:28:43 +0100 Subject: [PATCH] Make constant primops lazy --- src/libexpr/eval.cc | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) diff --git a/src/libexpr/eval.cc b/src/libexpr/eval.cc index 2a194d0e0..3891e8666 100644 --- a/src/libexpr/eval.cc +++ b/src/libexpr/eval.cc @@ -439,14 +439,21 @@ Value * EvalState::addConstant(const string & name, Value & v) Value * EvalState::addPrimOp(const string & name, size_t arity, PrimOpFun primOp) { + auto name2 = string(name, 0, 2) == "__" ? string(name, 2) : name; + Symbol sym = symbols.create(name2); + + /* Hack to make constants lazy: turn them into a application of + the primop to a dummy value. */ if (arity == 0) { + auto vPrimOp = allocValue(); + vPrimOp->type = tPrimOp; + vPrimOp->primOp = new PrimOp(primOp, 1, sym); Value v; - primOp(*this, noPos, nullptr, v); + mkApp(v, *vPrimOp, *vPrimOp); return addConstant(name, v); } + Value * v = allocValue(); - string name2 = string(name, 0, 2) == "__" ? string(name, 2) : name; - Symbol sym = symbols.create(name2); v->type = tPrimOp; v->primOp = new PrimOp(primOp, arity, sym); staticBaseEnv.vars[symbols.create(name)] = baseEnvDispl;