diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/libcmd/local.mk | 2 | ||||
| -rw-r--r-- | src/libcmd/meson.build | 5 | ||||
| -rw-r--r-- | src/libcmd/repl-overlays.nix | 8 | ||||
| -rw-r--r-- | src/libcmd/repl.cc | 165 | ||||
| -rw-r--r-- | src/libexpr/eval-settings.hh | 36 |
5 files changed, 214 insertions, 2 deletions
diff --git a/src/libcmd/local.mk b/src/libcmd/local.mk index dcd33e84c..5d0e3ed7e 100644 --- a/src/libcmd/local.mk +++ b/src/libcmd/local.mk @@ -13,3 +13,5 @@ libcmd_LDFLAGS = $(EDITLINE_LIBS) $(LOWDOWN_LIBS) $(NIXDOC_LIBS) -pthread libcmd_LIBS = libstore libutil libexpr libmain libfetchers $(eval $(call install-file-in, $(buildprefix)$(d)/nix-cmd.pc, $(libdir)/pkgconfig, 0644)) + +$(d)/repl.cc: $(d)/repl-overlays.nix.gen.hh diff --git a/src/libcmd/meson.build b/src/libcmd/meson.build index 867508926..b057daa37 100644 --- a/src/libcmd/meson.build +++ b/src/libcmd/meson.build @@ -32,8 +32,13 @@ libcmd_headers = files( 'repl.hh', ) +libcmd_generated_headers = [ + gen_header.process('repl-overlays.nix', preserve_path_from: meson.current_source_dir()), +] + libcmd = library( 'nixcmd', + libcmd_generated_headers, libcmd_sources, dependencies : [ liblixutil, diff --git a/src/libcmd/repl-overlays.nix b/src/libcmd/repl-overlays.nix new file mode 100644 index 000000000..33ce49482 --- /dev/null +++ b/src/libcmd/repl-overlays.nix @@ -0,0 +1,8 @@ +info: +initial: +functions: +let final = builtins.foldl' + (prev: function: prev // (function info final prev)) + initial + functions; +in final diff --git a/src/libcmd/repl.cc b/src/libcmd/repl.cc index ee3a6e268..4aa46dbc0 100644 --- a/src/libcmd/repl.cc +++ b/src/libcmd/repl.cc @@ -30,6 +30,7 @@ #include "signals.hh" #include "print.hh" #include "progress-bar.hh" +#include "gc-small-vector.hh" #if HAVE_BOEHMGC #define GC_INCLUDE_NEW @@ -118,6 +119,45 @@ struct NixRepl void evalString(std::string s, Value & v); void loadDebugTraceEnv(DebugTrace & dt); + /** + * Load the `repl-overlays` and add the resulting AttrSet to the top-level + * bindings. + */ + void loadReplOverlays(); + + /** + * Get a list of each of the `repl-overlays` (parsed and evaluated). + */ + Value * replOverlays(); + + /** + * Get the Nix function that composes the `repl-overlays` together. + */ + Value * getReplOverlaysEvalFunction(); + + /** + * Cached return value of `getReplOverlaysEvalFunction`. + * + * Note: This is `shared_ptr` to avoid garbage collection. + */ + std::shared_ptr<Value *> replOverlaysEvalFunction = + std::allocate_shared<Value *>(traceable_allocator<Value *>(), nullptr); + + /** + * Get the `info` AttrSet that's passed as the first argument to each + * of the `repl-overlays`. + */ + Value * replInitInfo(); + + /** + * Get the current top-level bindings as an AttrSet. + */ + Value * bindingsToAttrs(); + /** + * Parse a file, evaluate its result, and force the resulting value. + */ + Value * evalFile(SourcePath & path); + void printValue(std::ostream & str, Value & v, unsigned int maxDepth = std::numeric_limits<unsigned int>::max()) @@ -770,14 +810,114 @@ void NixRepl::loadFiles() loadedFiles.clear(); for (auto & i : old) { - notice("Loading '%1%'...", i); + notice("Loading '%1%'...", Magenta(i)); loadFile(i); } for (auto & [i, what] : getValues()) { - notice("Loading installable '%1%'...", what); + notice("Loading installable '%1%'...", Magenta(what)); addAttrsToScope(*i); } + + loadReplOverlays(); +} + +void NixRepl::loadReplOverlays() +{ + if (!evalSettings.replOverlays) { + return; + } + + notice("Loading '%1%'...", Magenta("repl-overlays")); + auto replInitFilesFunction = getReplOverlaysEvalFunction(); + + Value &newAttrs(*state->allocValue()); + SmallValueVector<3> args = {replInitInfo(), bindingsToAttrs(), replOverlays()}; + state->callFunction( + *replInitFilesFunction, + args.size(), + args.data(), + newAttrs, + replInitFilesFunction->determinePos(noPos) + ); + + addAttrsToScope(newAttrs); +} + +Value * NixRepl::getReplOverlaysEvalFunction() +{ + if (replOverlaysEvalFunction && *replOverlaysEvalFunction) { + return *replOverlaysEvalFunction; + } + + auto evalReplInitFilesPath = CanonPath::root + "repl-overlays.nix"; + *replOverlaysEvalFunction = state->allocValue(); + auto code = + #include "repl-overlays.nix.gen.hh" + ; + auto expr = state->parseExprFromString( + code, + SourcePath(evalReplInitFilesPath), + state->staticBaseEnv + ); + + state->eval(expr, **replOverlaysEvalFunction); + + return *replOverlaysEvalFunction; +} + +Value * NixRepl::replOverlays() +{ + Value * replInits(state->allocValue()); + state->mkList(*replInits, evalSettings.replOverlays.get().size()); + Value ** replInitElems = replInits->listElems(); + + size_t i = 0; + for (auto path : evalSettings.replOverlays.get()) { + debug("Loading '%1%' path '%2%'...", "repl-overlays", path); + SourcePath sourcePath((CanonPath(path))); + auto replInit = evalFile(sourcePath); + + if (!replInit->isLambda()) { + state->error<TypeError>( + "Expected `repl-overlays` to be a lambda but found %1%: %2%", + showType(*replInit), + ValuePrinter(*state, *replInit, errorPrintOptions) + ) + .atPos(replInit->determinePos(noPos)) + .debugThrow(); + } + + if (replInit->lambda.fun->hasFormals() + && !replInit->lambda.fun->formals->ellipsis) { + state->error<TypeError>( + "Expected first argument of %1% to have %2% to allow future versions of Lix to add additional attributes to the argument", + "repl-overlays", + "..." + ) + .atPos(replInit->determinePos(noPos)) + .debugThrow(); + } + + replInitElems[i] = replInit; + i++; + } + + + return replInits; +} + +Value * NixRepl::replInitInfo() +{ + auto builder = state->buildBindings(2); + + Value * currentSystem(state->allocValue()); + currentSystem->mkString(evalSettings.getCurrentSystem()); + builder.insert(state->symbols.create("currentSystem"), currentSystem); + + Value * info(state->allocValue()); + info->mkAttrs(builder.finish()); + return info; } @@ -810,6 +950,18 @@ void NixRepl::addVarToScope(const Symbol name, Value & v) varNames.emplace(state->symbols[name]); } +Value * NixRepl::bindingsToAttrs() +{ + auto builder = state->buildBindings(staticEnv->vars.size()); + for (auto & [symbol, displacement] : staticEnv->vars) { + builder.insert(symbol, env->values[displacement]); + } + + Value * attrs(state->allocValue()); + attrs->mkAttrs(builder.finish()); + return attrs; +} + Expr * NixRepl::parseString(std::string s) { @@ -824,6 +976,15 @@ void NixRepl::evalString(std::string s, Value & v) state->forceValue(v, v.determinePos(noPos)); } +Value * NixRepl::evalFile(SourcePath & path) +{ + auto expr = state->parseExprFromFile(path, staticEnv); + Value * result(state->allocValue()); + expr->eval(*state, *env, *result); + state->forceValue(*result, result->determinePos(noPos)); + return result; +} + std::unique_ptr<AbstractNixRepl> AbstractNixRepl::create( const SearchPath & searchPath, nix::ref<Store> store, ref<EvalState> state, diff --git a/src/libexpr/eval-settings.hh b/src/libexpr/eval-settings.hh index c78213255..e8bfe81a4 100644 --- a/src/libexpr/eval-settings.hh +++ b/src/libexpr/eval-settings.hh @@ -124,6 +124,42 @@ struct EvalSettings : Config This is useful for debugging warnings in third-party Nix code. )"}; + + PathsSetting replOverlays{this, Paths(), "repl-overlays", + R"( + A list of files containing Nix expressions that can be used to add + default bindings to [`nix + repl`](@docroot@/command-ref/new-cli/nix3-repl.md) sessions. + + Each file is called with three arguments: + 1. An [attribute set](@docroot@/language/values.html#attribute-set) + containing at least a + [`currentSystem`](@docroot@/language/builtin-constants.md#builtins-currentSystem) + attribute (this is identical to + [`builtins.currentSystem`](@docroot@/language/builtin-constants.md#builtins-currentSystem), + except that it's available in + [`pure-eval`](@docroot@/command-ref/conf-file.html#conf-pure-eval) + mode). + 2. The top-level bindings produced by the previous `repl-overlays` + value (or the default top-level bindings). + 3. The final top-level bindings produced by calling all + `repl-overlays`. + + For example, the following file would alias `pkgs` to + `legacyPackages.${info.currentSystem}` (if that attribute is defined): + + ```nix + info: final: prev: + if prev ? legacyPackages + && prev.legacyPackages ? ${info.currentSystem} + then + { + pkgs = prev.legacyPackages.${info.currentSystem}; + } + else + { } + ``` + )"}; }; extern EvalSettings evalSettings; |