diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/libexpr/eval.hh | 3 | ||||
| -rw-r--r-- | src/libexpr/primops.cc | 21 |
2 files changed, 24 insertions, 0 deletions
diff --git a/src/libexpr/eval.hh b/src/libexpr/eval.hh index 4eaa3c9b0..7db954bf4 100644 --- a/src/libexpr/eval.hh +++ b/src/libexpr/eval.hh @@ -646,6 +646,9 @@ struct EvalSettings : Config Setting<bool> useEvalCache{this, true, "eval-cache", "Whether to use the flake evaluation cache."}; + + Setting<bool> traceVerbose{this, false, "trace-verbose", + "Whether `builtins.traceVerbose` should trace its first argument when evaluated."}; }; extern EvalSettings evalSettings; diff --git a/src/libexpr/primops.cc b/src/libexpr/primops.cc index eea274301..5fda9af75 100644 --- a/src/libexpr/primops.cc +++ b/src/libexpr/primops.cc @@ -970,6 +970,15 @@ static RegisterPrimOp primop_trace({ }); +/* Takes two arguments and evaluates to the second one. Used as the + * builtins.traceVerbose implementation when --trace-verbose is not enabled + */ +static void prim_second(EvalState & state, const PosIdx pos, Value * * args, Value & v) +{ + state.forceValue(*args[1], pos); + v = *args[1]; +} + /************************************************************* * Derivations *************************************************************/ @@ -3926,6 +3935,18 @@ void EvalState::createBaseEnv() addPrimOp("__exec", 1, prim_exec); } + addPrimOp({ + .fun = evalSettings.traceVerbose ? prim_trace : prim_second, + .arity = 2, + .name = "__traceVerbose", + .args = { "e1", "e2" }, + .doc = R"( + Evaluate *e1* and print its abstract syntax representation on standard + error if `--trace-verbose` is enabled. Then return *e2*. This function + is useful for debugging. + )", + }); + /* Add a value containing the current Nix expression search path. */ mkList(v, searchPath.size()); int n = 0; |