lix/src/libexpr/primops/fromTOML.cc

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#include "primops.hh"
#include "eval-inline.hh"
#include "../../toml11/toml.hpp"
namespace nix {
static void prim_fromTOML(EvalState & state, const Pos & pos, Value * * args, Value & val)
{
auto toml = state.forceStringNoCtx(*args[0], pos);
std::istringstream tomlStream(string{toml});
std::function<void(Value &, toml::value)> visit;
visit = [&](Value & v, toml::value t) {
switch(t.type())
{
case toml::value_t::table:
{
auto table = toml::get<toml::table>(t);
size_t size = 0;
for (auto & i : table) { (void) i; size++; }
auto attrs = state.buildBindings(size);
for(auto & elem : table)
visit(attrs.alloc(elem.first), elem.second);
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v.mkAttrs(attrs);
}
break;;
case toml::value_t::array:
{
auto array = toml::get<std::vector<toml::value>>(t);
size_t size = array.size();
state.mkList(v, size);
for (size_t i = 0; i < size; ++i)
visit(*(v.listElems()[i] = state.allocValue()), array[i]);
}
break;;
case toml::value_t::boolean:
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v.mkBool(toml::get<bool>(t));
break;;
case toml::value_t::integer:
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v.mkInt(toml::get<int64_t>(t));
break;;
case toml::value_t::floating:
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v.mkFloat(toml::get<NixFloat>(t));
break;;
case toml::value_t::string:
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v.mkString(toml::get<std::string>(t));
break;;
case toml::value_t::local_datetime:
case toml::value_t::offset_datetime:
case toml::value_t::local_date:
case toml::value_t::local_time:
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// We fail since Nix doesn't have date and time types
throw std::runtime_error("Dates and times are not supported");
break;;
case toml::value_t::empty:
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v.mkNull();
break;;
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}
};
try {
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visit(val, toml::parse(tomlStream, "fromTOML" /* the "filename" */));
} catch (std::exception & e) { // TODO: toml::syntax_error
throw EvalError({
Improve error formatting Changes: * The divider lines are gone. These were in practice a bit confusing, in particular with --show-trace or --keep-going, since then there were multiple lines, suggesting a start/end which wasn't the case. * Instead, multi-line error messages are now indented to align with the prefix (e.g. "error: "). * The 'description' field is gone since we weren't really using it. * 'hint' is renamed to 'msg' since it really wasn't a hint. * The error is now printed *before* the location info. * The 'name' field is no longer printed since most of the time it wasn't very useful since it was just the name of the exception (like EvalError). Ideally in the future this would be a unique, easily googleable error ID (like rustc). * "trace:" is now just "…". This assumes error contexts start with something like "while doing X". Example before: error: --- AssertionError ---------------------------------------------------------------------------------------- nix at: (7:7) in file: /home/eelco/Dev/nixpkgs/pkgs/applications/misc/hello/default.nix 6| 7| x = assert false; 1; | ^ 8| assertion 'false' failed ----------------------------------------------------- show-trace ----------------------------------------------------- trace: while evaluating the attribute 'x' of the derivation 'hello-2.10' at: (192:11) in file: /home/eelco/Dev/nixpkgs/pkgs/stdenv/generic/make-derivation.nix 191| // (lib.optionalAttrs (!(attrs ? name) && attrs ? pname && attrs ? version)) { 192| name = "${attrs.pname}-${attrs.version}"; | ^ 193| } // (lib.optionalAttrs (stdenv.hostPlatform != stdenv.buildPlatform && !dontAddHostSuffix && (attrs ? name || (attrs ? pname && attrs ? version)))) { Example after: error: assertion 'false' failed at: (7:7) in file: /home/eelco/Dev/nixpkgs/pkgs/applications/misc/hello/default.nix 6| 7| x = assert false; 1; | ^ 8| … while evaluating the attribute 'x' of the derivation 'hello-2.10' at: (192:11) in file: /home/eelco/Dev/nixpkgs/pkgs/stdenv/generic/make-derivation.nix 191| // (lib.optionalAttrs (!(attrs ? name) && attrs ? pname && attrs ? version)) { 192| name = "${attrs.pname}-${attrs.version}"; | ^ 193| } // (lib.optionalAttrs (stdenv.hostPlatform != stdenv.buildPlatform && !dontAddHostSuffix && (attrs ? name || (attrs ? pname && attrs ? version)))) {
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.msg = hintfmt("while parsing a TOML string: %s", e.what()),
.errPos = pos
});
}
}
static RegisterPrimOp primop_fromTOML("fromTOML", 1, prim_fromTOML);
}