Merge "Add repl-overlays" into main
This commit is contained in:
rebecca “wiggles” turner
Gerrit Code Review
commit
a95c62673b
25 changed files with 355 additions and 3 deletions
36
doc/manual/rl-next/repl-overlays.md
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36
doc/manual/rl-next/repl-overlays.md
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@ -0,0 +1,36 @@
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---
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synopsis: Add `repl-overlays` option
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prs: 10203
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cls: 504
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---
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A `repl-overlays` option has been added, which specifies files that can overlay
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and modify the top-level bindings in `nix repl`. For example, with the
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following contents in `~/.config/nix/repl.nix`:
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```nix
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info: final: prev: let
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optionalAttrs = predicate: attrs:
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if predicate
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then attrs
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else {};
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in
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optionalAttrs (prev ? legacyPackages && prev.legacyPackages ? ${info.currentSystem})
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{
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pkgs = prev.legacyPackages.${info.currentSystem};
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}
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```
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We can run `nix repl` and use `pkgs` to refer to `legacyPackages.${currentSystem}`:
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```ShellSession
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$ nix repl --repl-overlays ~/.config/nix/repl.nix nixpkgs
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Lix 2.90.0
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Type :? for help.
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Loading installable 'flake:nixpkgs#'...
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Added 5 variables.
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Loading 'repl-overlays'...
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Added 6 variables.
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nix-repl> pkgs.bash
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«derivation /nix/store/g08b5vkwwh0j8ic9rkmd8mpj878rk62z-bash-5.2p26.drv»
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```
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@ -13,3 +13,5 @@ libcmd_LDFLAGS = $(EDITLINE_LIBS) $(LOWDOWN_LIBS) $(NIXDOC_LIBS) -pthread
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libcmd_LIBS = libstore libutil libexpr libmain libfetchers
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$(eval $(call install-file-in, $(buildprefix)$(d)/nix-cmd.pc, $(libdir)/pkgconfig, 0644))
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$(d)/repl.cc: $(d)/repl-overlays.nix.gen.hh
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@ -32,8 +32,13 @@ libcmd_headers = files(
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'repl.hh',
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)
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libcmd_generated_headers = [
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gen_header.process('repl-overlays.nix', preserve_path_from: meson.current_source_dir()),
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]
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libcmd = library(
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'nixcmd',
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libcmd_generated_headers,
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libcmd_sources,
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dependencies : [
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liblixutil,
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8
src/libcmd/repl-overlays.nix
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8
src/libcmd/repl-overlays.nix
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@ -0,0 +1,8 @@
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info:
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initial:
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functions:
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let final = builtins.foldl'
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(prev: function: prev // (function info final prev))
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initial
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functions;
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in final
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@ -30,6 +30,7 @@
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#include "signals.hh"
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#include "print.hh"
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#include "progress-bar.hh"
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#include "gc-small-vector.hh"
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#if HAVE_BOEHMGC
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#define GC_INCLUDE_NEW
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@ -118,6 +119,45 @@ struct NixRepl
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void evalString(std::string s, Value & v);
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void loadDebugTraceEnv(DebugTrace & dt);
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/**
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* Load the `repl-overlays` and add the resulting AttrSet to the top-level
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* bindings.
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*/
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void loadReplOverlays();
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/**
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* Get a list of each of the `repl-overlays` (parsed and evaluated).
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*/
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Value * replOverlays();
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/**
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* Get the Nix function that composes the `repl-overlays` together.
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*/
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Value * getReplOverlaysEvalFunction();
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/**
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* Cached return value of `getReplOverlaysEvalFunction`.
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*
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* Note: This is `shared_ptr` to avoid garbage collection.
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*/
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std::shared_ptr<Value *> replOverlaysEvalFunction =
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std::allocate_shared<Value *>(traceable_allocator<Value *>(), nullptr);
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/**
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* Get the `info` AttrSet that's passed as the first argument to each
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* of the `repl-overlays`.
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*/
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Value * replInitInfo();
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/**
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* Get the current top-level bindings as an AttrSet.
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*/
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Value * bindingsToAttrs();
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/**
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* Parse a file, evaluate its result, and force the resulting value.
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*/
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Value * evalFile(SourcePath & path);
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void printValue(std::ostream & str,
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Value & v,
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unsigned int maxDepth = std::numeric_limits<unsigned int>::max())
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@ -770,14 +810,114 @@ void NixRepl::loadFiles()
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loadedFiles.clear();
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for (auto & i : old) {
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notice("Loading '%1%'...", i);
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notice("Loading '%1%'...", Magenta(i));
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loadFile(i);
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}
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for (auto & [i, what] : getValues()) {
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notice("Loading installable '%1%'...", what);
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notice("Loading installable '%1%'...", Magenta(what));
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addAttrsToScope(*i);
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}
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loadReplOverlays();
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}
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void NixRepl::loadReplOverlays()
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{
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if (!evalSettings.replOverlays) {
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return;
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}
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notice("Loading '%1%'...", Magenta("repl-overlays"));
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auto replInitFilesFunction = getReplOverlaysEvalFunction();
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Value &newAttrs(*state->allocValue());
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SmallValueVector<3> args = {replInitInfo(), bindingsToAttrs(), replOverlays()};
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state->callFunction(
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*replInitFilesFunction,
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args.size(),
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args.data(),
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newAttrs,
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replInitFilesFunction->determinePos(noPos)
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);
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addAttrsToScope(newAttrs);
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}
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Value * NixRepl::getReplOverlaysEvalFunction()
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{
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if (replOverlaysEvalFunction && *replOverlaysEvalFunction) {
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return *replOverlaysEvalFunction;
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}
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auto evalReplInitFilesPath = CanonPath::root + "repl-overlays.nix";
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*replOverlaysEvalFunction = state->allocValue();
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auto code =
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#include "repl-overlays.nix.gen.hh"
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;
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auto expr = state->parseExprFromString(
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code,
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SourcePath(evalReplInitFilesPath),
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state->staticBaseEnv
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);
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state->eval(expr, **replOverlaysEvalFunction);
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return *replOverlaysEvalFunction;
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}
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Value * NixRepl::replOverlays()
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{
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Value * replInits(state->allocValue());
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state->mkList(*replInits, evalSettings.replOverlays.get().size());
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Value ** replInitElems = replInits->listElems();
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size_t i = 0;
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for (auto path : evalSettings.replOverlays.get()) {
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debug("Loading '%1%' path '%2%'...", "repl-overlays", path);
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SourcePath sourcePath((CanonPath(path)));
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auto replInit = evalFile(sourcePath);
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if (!replInit->isLambda()) {
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state->error<TypeError>(
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"Expected `repl-overlays` to be a lambda but found %1%: %2%",
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showType(*replInit),
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ValuePrinter(*state, *replInit, errorPrintOptions)
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)
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.atPos(replInit->determinePos(noPos))
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.debugThrow();
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}
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if (replInit->lambda.fun->hasFormals()
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&& !replInit->lambda.fun->formals->ellipsis) {
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state->error<TypeError>(
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"Expected first argument of %1% to have %2% to allow future versions of Lix to add additional attributes to the argument",
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"repl-overlays",
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"..."
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)
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.atPos(replInit->determinePos(noPos))
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.debugThrow();
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}
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replInitElems[i] = replInit;
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i++;
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}
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return replInits;
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}
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Value * NixRepl::replInitInfo()
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{
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auto builder = state->buildBindings(2);
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Value * currentSystem(state->allocValue());
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currentSystem->mkString(evalSettings.getCurrentSystem());
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builder.insert(state->symbols.create("currentSystem"), currentSystem);
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Value * info(state->allocValue());
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info->mkAttrs(builder.finish());
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return info;
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}
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@ -810,6 +950,18 @@ void NixRepl::addVarToScope(const Symbol name, Value & v)
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varNames.emplace(state->symbols[name]);
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}
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Value * NixRepl::bindingsToAttrs()
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{
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auto builder = state->buildBindings(staticEnv->vars.size());
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for (auto & [symbol, displacement] : staticEnv->vars) {
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builder.insert(symbol, env->values[displacement]);
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}
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Value * attrs(state->allocValue());
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attrs->mkAttrs(builder.finish());
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return attrs;
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}
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Expr * NixRepl::parseString(std::string s)
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{
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@ -824,6 +976,15 @@ void NixRepl::evalString(std::string s, Value & v)
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state->forceValue(v, v.determinePos(noPos));
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}
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Value * NixRepl::evalFile(SourcePath & path)
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{
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auto expr = state->parseExprFromFile(path, staticEnv);
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Value * result(state->allocValue());
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expr->eval(*state, *env, *result);
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state->forceValue(*result, result->determinePos(noPos));
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return result;
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}
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std::unique_ptr<AbstractNixRepl> AbstractNixRepl::create(
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const SearchPath & searchPath, nix::ref<Store> store, ref<EvalState> state,
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@ -125,6 +125,42 @@ struct EvalSettings : Config
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This is useful for debugging warnings in third-party Nix code.
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)"};
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PathsSetting replOverlays{this, Paths(), "repl-overlays",
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R"(
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A list of files containing Nix expressions that can be used to add
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default bindings to [`nix
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repl`](@docroot@/command-ref/new-cli/nix3-repl.md) sessions.
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Each file is called with three arguments:
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1. An [attribute set](@docroot@/language/values.html#attribute-set)
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containing at least a
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[`currentSystem`](@docroot@/language/builtin-constants.md#builtins-currentSystem)
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attribute (this is identical to
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[`builtins.currentSystem`](@docroot@/language/builtin-constants.md#builtins-currentSystem),
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except that it's available in
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[`pure-eval`](@docroot@/command-ref/conf-file.html#conf-pure-eval)
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mode).
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2. The top-level bindings produced by the previous `repl-overlays`
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value (or the default top-level bindings).
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3. The final top-level bindings produced by calling all
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`repl-overlays`.
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For example, the following file would alias `pkgs` to
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`legacyPackages.${info.currentSystem}` (if that attribute is defined):
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```nix
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info: final: prev:
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if prev ? legacyPackages
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&& prev.legacyPackages ? ${info.currentSystem}
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then
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{
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pkgs = prev.legacyPackages.${info.currentSystem};
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}
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else
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{ }
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```
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)"};
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};
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extern EvalSettings evalSettings;
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@ -0,0 +1 @@
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info: final: prev: builtins.abort "uh oh!"
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@ -0,0 +1,6 @@
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let
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puppy = "doggy";
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in
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{currentSystem}: final: prev: {
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inherit puppy;
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}
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@ -0,0 +1 @@
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info: final: prev: {}
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@ -0,0 +1,4 @@
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info: final: prev:
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{
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pkgs = final.packages.x86_64-linux;
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}
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@ -0,0 +1,7 @@
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info: final: prev:
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{
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var = prev.var + "b";
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# We can access the final value of `var` here even though it isn't defined yet:
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varUsingFinal = "final value is: " + final.newVar;
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}
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@ -0,0 +1,6 @@
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info: final: prev:
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{
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var = prev.var + "c";
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newVar = "puppy";
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}
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@ -0,0 +1,3 @@
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{
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packages.x86_64-linux.default = "my package";
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}
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@ -0,0 +1,5 @@
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Check basic `repl-overlays` functionality.
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@args --repl-overlays
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@args ${PWD}/extra_data/repl-overlay-packages-is-pkgs.nix
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nix-repl> pkgs
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{ default = "my package"; }
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@ -0,0 +1,3 @@
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{
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var = "a";
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}
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@ -0,0 +1,7 @@
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Check that multiple `repl-overlays` can compose together
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@args --repl-overlays
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@args "${PWD}/extra_data/repl-overlays-compose-1.nix ${PWD}/extra_data/repl-overlays-compose-2.nix"
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nix-repl> var
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"abc"
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nix-repl> varUsingFinal
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"final value is: puppy"
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@ -0,0 +1,10 @@
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`repl-overlays` that try to parse out the `info` argument without a `...` error.
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@args --repl-overlays
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@args ${PWD}/extra_data/repl-overlay-no-dotdotdot.nix
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@should-start false
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error: Expected first argument of repl-overlays to have ... to allow future versions of Lix to add additional attributes to the argument
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at $TEST_DATA/extra_data/repl-overlay-no-dotdotdot.nix:4:3:
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3| in
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4| {currentSystem}: final: prev: {
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| ^
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5| inherit puppy;\n
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@ -0,0 +1,5 @@
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`repl-overlays` that don't destructure the `info` argument are OK.
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@args --repl-overlays
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@args ${PWD}/extra_data/repl-overlay-no-formals.nix
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nix-repl> 1
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1
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@ -0,0 +1,22 @@
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`repl-overlays` that fail to evaluate should error.
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@args --repl-overlays
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@args ${PWD}/extra_data/repl-overlay-fail.nix
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@should-start false
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error:
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… while calling the 'foldl'' builtin
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at «string»:5:13:
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4| functions:
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5| let final = builtins.foldl'
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| ^
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6| (prev: function: prev // (function info final prev))
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… in the right operand of the update (//) operator
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at «string»:6:37:
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5| let final = builtins.foldl'
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6| (prev: function: prev // (function info final prev))
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| ^
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7| initial
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(stack trace truncated; use '--show-trace' to show the full trace)
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error: evaluation aborted with the following error message: 'uh oh!'
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|
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@ -0,0 +1 @@
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info: final: prev: builtins.abort "uh oh!"
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@ -0,0 +1 @@
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{currentSystem}: final: prev: {}
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@ -0,0 +1,4 @@
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info: final: prev:
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{
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pkgs = final.packages.x86_64-linux;
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}
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|
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@ -0,0 +1,7 @@
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info: final: prev:
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{
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var = prev.var + "b";
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# We can access the final value of `var` here even though it isn't defined yet:
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varUsingFinal = "final value is: " + final.newVar;
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}
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|
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@ -0,0 +1,6 @@
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info: final: prev:
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{
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var = prev.var + "c";
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newVar = "puppy";
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}
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@ -179,7 +179,12 @@ REPL_TEST(no_nested_debuggers);
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REPL_TEST(regression_9917);
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REPL_TEST(regression_9918);
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REPL_TEST(regression_l145);
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REPL_TEST(stack_vars);
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REPL_TEST(repl_overlays);
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REPL_TEST(repl_overlays_compose);
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REPL_TEST(repl_overlays_destructure_without_dotdotdot_errors);
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REPL_TEST(repl_overlays_destructure_without_formals_ok);
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REPL_TEST(repl_overlays_error);
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REPL_TEST(repl_printing);
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REPL_TEST(stack_vars);
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|
||||
}; // namespace nix
|
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|
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