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lix/src/libcmd/repl.cc

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#include <iostream>
#include <cstdlib>
#include <cstring>
#include <climits>
#include <setjmp.h>
#ifdef READLINE
#include <readline/history.h>
#include <readline/readline.h>
#else
// editline < 1.15.2 don't wrap their API for C++ usage
// (added in https://github.com/troglobit/editline/commit/91398ceb3427b730995357e9d120539fb9bb7461).
// This results in linker errors due to to name-mangling of editline C symbols.
// For compatibility with these versions, we wrap the API here
// (wrapping multiple times on newer versions is no problem).
extern "C" {
#include <editline.h>
}
#endif
#include "ansicolor.hh"
#include "shared.hh"
#include "eval.hh"
#include "eval-cache.hh"
#include "eval-inline.hh"
#include "attr-path.hh"
#include "store-api.hh"
#include "log-store.hh"
#include "common-eval-args.hh"
#include "get-drvs.hh"
#include "derivations.hh"
#include "globals.hh"
#include "command.hh"
#include "finally.hh"
#include "markdown.hh"
#include "local-fs-store.hh"
#include "progress-bar.hh"
#if HAVE_BOEHMGC
#define GC_INCLUDE_NEW
#include <gc/gc_cpp.h>
#endif
namespace nix {
struct NixRepl
#if HAVE_BOEHMGC
: gc
#endif
{
std::string curDir;
ref<EvalState> state;
Bindings * autoArgs;
size_t debugTraceIndex;
Strings loadedFiles;
typedef std::vector<std::pair<Value*,std::string>> AnnotatedValues;
std::function<AnnotatedValues()> getValues;
const static int envSize = 32768;
std::shared_ptr<StaticEnv> staticEnv;
Env * env;
int displ;
StringSet varNames;
const Path historyFile;
NixRepl(const Strings & searchPath, nix::ref<Store> store,ref<EvalState> state,
std::function<AnnotatedValues()> getValues);
~NixRepl();
void mainLoop();
StringSet completePrefix(const std::string & prefix);
bool getLine(std::string & input, const std::string & prompt);
StorePath getDerivationPath(Value & v);
bool processLine(std::string line);
void loadFile(const Path & path);
void loadFlake(const std::string & flakeRef);
void initEnv();
void loadFiles();
void reloadFiles();
void addAttrsToScope(Value & attrs);
void addVarToScope(const Symbol name, Value & v);
Expr * parseString(std::string s);
void evalString(std::string s, Value & v);
void loadDebugTraceEnv(DebugTrace & dt);
typedef std::set<Value *> ValuesSeen;
std::ostream & printValue(std::ostream & str, Value & v, unsigned int maxDepth);
std::ostream & printValue(std::ostream & str, Value & v, unsigned int maxDepth, ValuesSeen & seen);
};
std::string removeWhitespace(std::string s)
{
s = chomp(s);
size_t n = s.find_first_not_of(" \n\r\t");
if (n != std::string::npos) s = std::string(s, n);
return s;
}
NixRepl::NixRepl(const Strings & searchPath, nix::ref<Store> store, ref<EvalState> state,
std::function<NixRepl::AnnotatedValues()> getValues)
: state(state)
, debugTraceIndex(0)
, getValues(getValues)
, staticEnv(new StaticEnv(false, state->staticBaseEnv.get()))
, historyFile(getDataDir() + "/nix/repl-history")
{
curDir = absPath(".");
}
NixRepl::~NixRepl()
{
write_history(historyFile.c_str());
}
void runNix(Path program, const Strings & args,
const std::optional<std::string> & input = {})
{
auto subprocessEnv = getEnv();
subprocessEnv["NIX_CONFIG"] = globalConfig.toKeyValue();
runProgram2(RunOptions {
.program = settings.nixBinDir+ "/" + program,
.args = args,
.environment = subprocessEnv,
.input = input,
});
return;
}
static NixRepl * curRepl; // ugly
static char * completionCallback(char * s, int *match) {
auto possible = curRepl->completePrefix(s);
if (possible.size() == 1) {
*match = 1;
auto *res = strdup(possible.begin()->c_str() + strlen(s));
if (!res) throw Error("allocation failure");
return res;
} else if (possible.size() > 1) {
auto checkAllHaveSameAt = [&](size_t pos) {
auto &first = *possible.begin();
for (auto &p : possible) {
if (p.size() <= pos || p[pos] != first[pos])
return false;
}
return true;
};
size_t start = strlen(s);
size_t len = 0;
while (checkAllHaveSameAt(start + len)) ++len;
if (len > 0) {
*match = 1;
auto *res = strdup(std::string(*possible.begin(), start, len).c_str());
if (!res) throw Error("allocation failure");
return res;
}
}
*match = 0;
return nullptr;
}
static int listPossibleCallback(char *s, char ***avp) {
auto possible = curRepl->completePrefix(s);
if (possible.size() > (INT_MAX / sizeof(char*)))
throw Error("too many completions");
int ac = 0;
char **vp = nullptr;
auto check = [&](auto *p) {
if (!p) {
if (vp) {
while (--ac >= 0)
free(vp[ac]);
free(vp);
}
throw Error("allocation failure");
}
return p;
};
vp = check((char **)malloc(possible.size() * sizeof(char*)));
for (auto & p : possible)
vp[ac++] = check(strdup(p.c_str()));
*avp = vp;
return ac;
}
namespace {
// Used to communicate to NixRepl::getLine whether a signal occurred in ::readline.
volatile sig_atomic_t g_signal_received = 0;
void sigintHandler(int signo) {
g_signal_received = signo;
}
}
static std::ostream & showDebugTrace(std::ostream & out, const PosTable & positions, const DebugTrace & dt)
{
if (dt.isError)
out << ANSI_RED "error: " << ANSI_NORMAL;
out << dt.hint.str() << "\n";
// prefer direct pos, but if noPos then try the expr.
auto pos = dt.pos
? dt.pos
: static_cast<std::shared_ptr<AbstractPos>>(positions[dt.expr.getPos() ? dt.expr.getPos() : noPos]);
if (pos) {
out << pos;
if (auto loc = pos->getCodeLines()) {
out << "\n";
printCodeLines(out, "", *pos, *loc);
out << "\n";
}
}
return out;
}
void NixRepl::mainLoop()
{
std::string error = ANSI_RED "error:" ANSI_NORMAL " ";
notice("Welcome to Nix " + nixVersion + ". Type :? for help.\n");
loadFiles();
// Allow nix-repl specific settings in .inputrc
rl_readline_name = "nix-repl";
try {
createDirs(dirOf(historyFile));
} catch (SysError & e) {
logWarning(e.info());
}
#ifndef READLINE
el_hist_size = 1000;
#endif
read_history(historyFile.c_str());
curRepl = this;
#ifndef READLINE
rl_set_complete_func(completionCallback);
rl_set_list_possib_func(listPossibleCallback);
#endif
/* Stop the progress bar because it interferes with the display of
the repl. */
stopProgressBar();
std::string input;
while (true) {
// When continuing input from previous lines, don't print a prompt, just align to the same
// number of chars as the prompt.
if (!getLine(input, input.empty() ? "nix-repl> " : " ")) {
// ctrl-D should exit the debugger.
state->debugStop = false;
state->debugQuit = true;
logger->cout("");
break;
}
try {
if (!removeWhitespace(input).empty() && !processLine(input)) return;
} catch (ParseError & e) {
if (e.msg().find("unexpected end of file") != std::string::npos) {
// For parse errors on incomplete input, we continue waiting for the next line of
// input without clearing the input so far.
continue;
} else {
printMsg(lvlError, e.msg());
}
} catch (EvalError & e) {
// in debugger mode, an EvalError should trigger another repl session.
// when that session returns the exception will land here. No need to show it again;
// show the error for this repl session instead.
if (state->debugRepl && !state->debugTraces.empty())
showDebugTrace(std::cout, state->positions, state->debugTraces.front());
else
printMsg(lvlError, e.msg());
} catch (Error & e) {
printMsg(lvlError, e.msg());
} catch (Interrupted & e) {
printMsg(lvlError, e.msg());
}
// We handled the current input fully, so we should clear it
// and read brand new input.
input.clear();
std::cout << std::endl;
}
}
bool NixRepl::getLine(std::string & input, const std::string & prompt)
{
struct sigaction act, old;
sigset_t savedSignalMask, set;
auto setupSignals = [&]() {
act.sa_handler = sigintHandler;
sigfillset(&act.sa_mask);
act.sa_flags = 0;
if (sigaction(SIGINT, &act, &old))
throw SysError("installing handler for SIGINT");
sigemptyset(&set);
sigaddset(&set, SIGINT);
if (sigprocmask(SIG_UNBLOCK, &set, &savedSignalMask))
throw SysError("unblocking SIGINT");
};
auto restoreSignals = [&]() {
if (sigprocmask(SIG_SETMASK, &savedSignalMask, nullptr))
throw SysError("restoring signals");
if (sigaction(SIGINT, &old, 0))
throw SysError("restoring handler for SIGINT");
};
setupSignals();
Finally resetTerminal([&]() { rl_deprep_terminal(); });
char * s = readline(prompt.c_str());
Finally doFree([&]() { free(s); });
restoreSignals();
if (g_signal_received) {
g_signal_received = 0;
input.clear();
return true;
}
if (!s)
return false;
input += s;
input += '\n';
return true;
}
StringSet NixRepl::completePrefix(const std::string & prefix)
{
StringSet completions;
size_t start = prefix.find_last_of(" \n\r\t(){}[]");
std::string prev, cur;
if (start == std::string::npos) {
prev = "";
cur = prefix;
} else {
prev = std::string(prefix, 0, start + 1);
cur = std::string(prefix, start + 1);
}
size_t slash, dot;
if ((slash = cur.rfind('/')) != std::string::npos) {
try {
auto dir = std::string(cur, 0, slash);
auto prefix2 = std::string(cur, slash + 1);
for (auto & entry : readDirectory(dir == "" ? "/" : dir)) {
if (entry.name[0] != '.' && hasPrefix(entry.name, prefix2))
completions.insert(prev + dir + "/" + entry.name);
}
} catch (Error &) {
}
} else if ((dot = cur.rfind('.')) == std::string::npos) {
/* This is a variable name; look it up in the current scope. */
StringSet::iterator i = varNames.lower_bound(cur);
while (i != varNames.end()) {
if (i->substr(0, cur.size()) != cur) break;
completions.insert(prev + *i);
i++;
}
} else {
/* Temporarily disable the debugger, to avoid re-entering readline. */
auto debug_repl = state->debugRepl;
state->debugRepl = nullptr;
Finally restoreDebug([&]() { state->debugRepl = debug_repl; });
try {
/* This is an expression that should evaluate to an
attribute set. Evaluate it to get the names of the
attributes. */
auto expr = cur.substr(0, dot);
auto cur2 = cur.substr(dot + 1);
Expr * e = parseString(expr);
Value v;
e->eval(*state, *env, v);
state->forceAttrs(v, noPos, "nevermind, it is ignored anyway");
for (auto & i : *v.attrs) {
std::string_view name = state->symbols[i.name];
if (name.substr(0, cur2.size()) != cur2) continue;
completions.insert(concatStrings(prev, expr, ".", name));
}
} catch (ParseError & e) {
// Quietly ignore parse errors.
} catch (EvalError & e) {
// Quietly ignore evaluation errors.
} catch (UndefinedVarError & e) {
// Quietly ignore undefined variable errors.
} catch (BadURL & e) {
// Quietly ignore BadURL flake-related errors.
}
}
return completions;
}
static bool isVarName(std::string_view s)
{
if (s.size() == 0) return false;
char c = s[0];
if ((c >= '0' && c <= '9') || c == '-' || c == '\'') return false;
for (auto & i : s)
if (!((i >= 'a' && i <= 'z') ||
(i >= 'A' && i <= 'Z') ||
(i >= '0' && i <= '9') ||
i == '_' || i == '-' || i == '\''))
return false;
return true;
}
StorePath NixRepl::getDerivationPath(Value & v) {
auto drvInfo = getDerivation(*state, v, false);
if (!drvInfo)
throw Error("expression does not evaluate to a derivation, so I can't build it");
auto drvPath = drvInfo->queryDrvPath();
if (!drvPath)
throw Error("expression did not evaluate to a valid derivation (no 'drvPath' attribute)");
if (!state->store->isValidPath(*drvPath))
throw Error("expression evaluated to invalid derivation '%s'", state->store->printStorePath(*drvPath));
return *drvPath;
}
void NixRepl::loadDebugTraceEnv(DebugTrace & dt)
{
initEnv();
auto se = state->getStaticEnv(dt.expr);
if (se) {
auto vm = mapStaticEnvBindings(state->symbols, *se.get(), dt.env);
// add staticenv vars.
for (auto & [name, value] : *(vm.get()))
addVarToScope(state->symbols.create(name), *value);
}
}
bool NixRepl::processLine(std::string line)
{
line = trim(line);
if (line == "") return true;
_isInterrupted = false;
std::string command, arg;
if (line[0] == ':') {
size_t p = line.find_first_of(" \n\r\t");
command = line.substr(0, p);
if (p != std::string::npos) arg = removeWhitespace(line.substr(p));
} else {
arg = line;
}
if (command == ":?" || command == ":help") {
// FIXME: convert to Markdown, include in the 'nix repl' manpage.
std::cout
<< "The following commands are available:\n"
<< "\n"
<< " <expr> Evaluate and print expression\n"
<< " <x> = <expr> Bind expression to variable\n"
<< " :a <expr> Add attributes from resulting set to scope\n"
<< " :b <expr> Build a derivation\n"
<< " :bl <expr> Build a derivation, creating GC roots in the working directory\n"
<< " :e <expr> Open package or function in $EDITOR\n"
<< " :i <expr> Build derivation, then install result into current profile\n"
<< " :l <path> Load Nix expression and add it to scope\n"
<< " :lf <ref> Load Nix flake and add it to scope\n"
<< " :p <expr> Evaluate and print expression recursively\n"
<< " :q Exit nix-repl\n"
<< " :r Reload all files\n"
<< " :sh <expr> Build dependencies of derivation, then start nix-shell\n"
<< " :t <expr> Describe result of evaluation\n"
<< " :u <expr> Build derivation, then start nix-shell\n"
<< " :doc <expr> Show documentation of a builtin function\n"
<< " :log <expr> Show logs for a derivation\n"
<< " :te [bool] Enable, disable or toggle showing traces for errors\n"
;
if (state->debugRepl) {
std::cout
<< "\n"
<< " Debug mode commands\n"
<< " :env Show env stack\n"
<< " :bt Show trace stack\n"
<< " :st Show current trace\n"
<< " :st <idx> Change to another trace in the stack\n"
<< " :c Go until end of program, exception, or builtins.break\n"
<< " :s Go one step\n"
;
}
}
else if (state->debugRepl && (command == ":bt" || command == ":backtrace")) {
for (const auto & [idx, i] : enumerate(state->debugTraces)) {
std::cout << "\n" << ANSI_BLUE << idx << ANSI_NORMAL << ": ";
showDebugTrace(std::cout, state->positions, i);
}
}
else if (state->debugRepl && (command == ":env")) {
for (const auto & [idx, i] : enumerate(state->debugTraces)) {
if (idx == debugTraceIndex) {
printEnvBindings(*state, i.expr, i.env);
break;
}
}
}
else if (state->debugRepl && (command == ":st")) {
try {
// change the DebugTrace index.
debugTraceIndex = stoi(arg);
} catch (...) { }
for (const auto & [idx, i] : enumerate(state->debugTraces)) {
if (idx == debugTraceIndex) {
std::cout << "\n" << ANSI_BLUE << idx << ANSI_NORMAL << ": ";
showDebugTrace(std::cout, state->positions, i);
std::cout << std::endl;
printEnvBindings(*state, i.expr, i.env);
loadDebugTraceEnv(i);
break;
}
}
}
else if (state->debugRepl && (command == ":s" || command == ":step")) {
// set flag to stop at next DebugTrace; exit repl.
state->debugStop = true;
return false;
}
else if (state->debugRepl && (command == ":c" || command == ":continue")) {
// set flag to run to next breakpoint or end of program; exit repl.
state->debugStop = false;
return false;
}
else if (command == ":a" || command == ":add") {
Value v;
evalString(arg, v);
addAttrsToScope(v);
}
else if (command == ":l" || command == ":load") {
state->resetFileCache();
loadFile(arg);
}
else if (command == ":lf" || command == ":load-flake") {
loadFlake(arg);
}
else if (command == ":r" || command == ":reload") {
state->resetFileCache();
reloadFiles();
}
else if (command == ":e" || command == ":edit") {
Value v;
evalString(arg, v);
const auto [path, line] = [&] () -> std::pair<Path, uint32_t> {
if (v.type() == nPath || v.type() == nString) {
PathSet context;
auto path = state->coerceToPath(noPos, v, context, "while evaluating the filename to edit");
return {path, 0};
} else if (v.isLambda()) {
auto pos = state->positions[v.lambda.fun->pos];
if (auto path = std::get_if<Path>(&pos.origin))
return {*path, pos.line};
else
throw Error("'%s' cannot be shown in an editor", pos);
} else {
// assume it's a derivation
return findPackageFilename(*state, v, arg);
}
}();
// Open in EDITOR
auto args = editorFor(path, line);
auto editor = args.front();
args.pop_front();
// runProgram redirects stdout to a StringSink,
// using runProgram2 to allow editors to display their UI
runProgram2(RunOptions { .program = editor, .searchPath = true, .args = args });
// Reload right after exiting the editor
state->resetFileCache();
reloadFiles();
}
else if (command == ":t") {
Value v;
evalString(arg, v);
logger->cout(showType(v));
}
else if (command == ":u") {
Value v, f, result;
evalString(arg, v);
evalString("drv: (import <nixpkgs> {}).runCommand \"shell\" { buildInputs = [ drv ]; } \"\"", f);
state->callFunction(f, v, result, PosIdx());
StorePath drvPath = getDerivationPath(result);
runNix("nix-shell", {state->store->printStorePath(drvPath)});
}
else if (command == ":b" || command == ":bl" || command == ":i" || command == ":sh" || command == ":log") {
Value v;
evalString(arg, v);
StorePath drvPath = getDerivationPath(v);
Path drvPathRaw = state->store->printStorePath(drvPath);
if (command == ":b" || command == ":bl") {
state->store->buildPaths({DerivedPath::Built{drvPath}});
auto drv = state->store->readDerivation(drvPath);
logger->cout("\nThis derivation produced the following outputs:");
for (auto & [outputName, outputPath] : state->store->queryDerivationOutputMap(drvPath)) {
auto localStore = state->store.dynamic_pointer_cast<LocalFSStore>();
if (localStore && command == ":bl") {
std::string symlink = "repl-result-" + outputName;
localStore->addPermRoot(outputPath, absPath(symlink));
logger->cout(" ./%s -> %s", symlink, state->store->printStorePath(outputPath));
} else {
logger->cout(" %s -> %s", outputName, state->store->printStorePath(outputPath));
}
}
} else if (command == ":i") {
runNix("nix-env", {"-i", drvPathRaw});
} else if (command == ":log") {
settings.readOnlyMode = true;
Finally roModeReset([&]() {
settings.readOnlyMode = false;
});
auto subs = getDefaultSubstituters();
subs.push_front(state->store);
bool foundLog = false;
RunPager pager;
for (auto & sub : subs) {
auto * logSubP = dynamic_cast<LogStore *>(&*sub);
if (!logSubP) {
printInfo("Skipped '%s' which does not support retrieving build logs", sub->getUri());
continue;
}
auto & logSub = *logSubP;
auto log = logSub.getBuildLog(drvPath);
if (log) {
printInfo("got build log for '%s' from '%s'", drvPathRaw, logSub.getUri());
logger->writeToStdout(*log);
foundLog = true;
break;
}
}
if (!foundLog) throw Error("build log of '%s' is not available", drvPathRaw);
} else {
runNix("nix-shell", {drvPathRaw});
}
}
else if (command == ":p" || command == ":print") {
Value v;
evalString(arg, v);
printValue(std::cout, v, 1000000000) << std::endl;
}
else if (command == ":q" || command == ":quit") {
state->debugStop = false;
state->debugQuit = true;
return false;
}
else if (command == ":doc") {
Value v;
evalString(arg, v);
if (auto doc = state->getDoc(v)) {
std::string markdown;
if (!doc->args.empty() && doc->name) {
auto args = doc->args;
for (auto & arg : args)
arg = "*" + arg + "*";
markdown +=
"**Synopsis:** `builtins." + (std::string) (*doc->name) + "` "
+ concatStringsSep(" ", args) + "\n\n";
}
markdown += stripIndentation(doc->doc);
logger->cout(trim(renderMarkdownToTerminal(markdown)));
} else
throw Error("value does not have documentation");
}
else if (command == ":te" || command == ":trace-enable") {
if (arg == "false" || (arg == "" && loggerSettings.showTrace)) {
std::cout << "not showing error traces\n";
loggerSettings.showTrace = false;
} else if (arg == "true" || (arg == "" && !loggerSettings.showTrace)) {
std::cout << "showing error traces\n";
loggerSettings.showTrace = true;
} else {
throw Error("unexpected argument '%s' to %s", arg, command);
};
}
else if (command != "")
throw Error("unknown command '%1%'", command);
else {
size_t p = line.find('=');
std::string name;
if (p != std::string::npos &&
p < line.size() &&
line[p + 1] != '=' &&
isVarName(name = removeWhitespace(line.substr(0, p))))
{
Expr * e = parseString(line.substr(p + 1));
Value & v(*state->allocValue());
v.mkThunk(env, e);
addVarToScope(state->symbols.create(name), v);
} else {
Value v;
evalString(line, v);
printValue(std::cout, v, 1) << std::endl;
}
}
return true;
}
void NixRepl::loadFile(const Path & path)
{
loadedFiles.remove(path);
loadedFiles.push_back(path);
Value v, v2;
state->evalFile(lookupFileArg(*state, path), v);
state->autoCallFunction(*autoArgs, v, v2);
addAttrsToScope(v2);
}
void NixRepl::loadFlake(const std::string & flakeRefS)
{
if (flakeRefS.empty())
throw Error("cannot use ':load-flake' without a path specified. (Use '.' for the current working directory.)");
auto flakeRef = parseFlakeRef(flakeRefS, absPath("."), true);
if (evalSettings.pureEval && !flakeRef.input.isLocked())
throw Error("cannot use ':load-flake' on locked flake reference '%s' (use --impure to override)", flakeRefS);
Value v;
flake::callFlake(*state,
flake::lockFlake(*state, flakeRef,
flake::LockFlags {
.updateLockFile = false,
.useRegistries = !evalSettings.pureEval,
.allowUnlocked = !evalSettings.pureEval,
}),
v);
addAttrsToScope(v);
}
void NixRepl::initEnv()
{
env = &state->allocEnv(envSize);
env->up = &state->baseEnv;
displ = 0;
staticEnv->vars.clear();
varNames.clear();
for (auto & i : state->staticBaseEnv->vars)
varNames.emplace(state->symbols[i.first]);
}
void NixRepl::reloadFiles()
{
initEnv();
loadFiles();
}
void NixRepl::loadFiles()
{
Strings old = loadedFiles;
loadedFiles.clear();
for (auto & i : old) {
notice("Loading '%1%'...", i);
loadFile(i);
}
for (auto & [i, what] : getValues()) {
notice("Loading installable '%1%'...", what);
addAttrsToScope(*i);
}
}
void NixRepl::addAttrsToScope(Value & attrs)
{
state->forceAttrs(attrs, [&]() { return attrs.determinePos(noPos); }, "while evaluating an attribute set to be merged in the global scope");
if (displ + attrs.attrs->size() >= envSize)
throw Error("environment full; cannot add more variables");
for (auto & i : *attrs.attrs) {
staticEnv->vars.emplace_back(i.name, displ);
env->values[displ++] = i.value;
varNames.emplace(state->symbols[i.name]);
}
staticEnv->sort();
staticEnv->deduplicate();
notice("Added %1% variables.", attrs.attrs->size());
}
void NixRepl::addVarToScope(const Symbol name, Value & v)
{
if (displ >= envSize)
throw Error("environment full; cannot add more variables");
if (auto oldVar = staticEnv->find(name); oldVar != staticEnv->vars.end())
staticEnv->vars.erase(oldVar);
staticEnv->vars.emplace_back(name, displ);
staticEnv->sort();
env->values[displ++] = &v;
varNames.emplace(state->symbols[name]);
}
Expr * NixRepl::parseString(std::string s)
{
Expr * e = state->parseExprFromString(std::move(s), curDir, staticEnv);
return e;
}
void NixRepl::evalString(std::string s, Value & v)
{
Expr * e = parseString(s);
e->eval(*state, *env, v);
state->forceValue(v, [&]() { return v.determinePos(noPos); });
}
std::ostream & NixRepl::printValue(std::ostream & str, Value & v, unsigned int maxDepth)
{
ValuesSeen seen;
return printValue(str, v, maxDepth, seen);
}
std::ostream & printStringValue(std::ostream & str, const char * string) {
str << "\"";
for (const char * i = string; *i; i++)
if (*i == '\"' || *i == '\\') str << "\\" << *i;
else if (*i == '\n') str << "\\n";
else if (*i == '\r') str << "\\r";
else if (*i == '\t') str << "\\t";
else str << *i;
str << "\"";
return str;
}
// FIXME: lot of cut&paste from Nix's eval.cc.
std::ostream & NixRepl::printValue(std::ostream & str, Value & v, unsigned int maxDepth, ValuesSeen & seen)
{
str.flush();
checkInterrupt();
state->forceValue(v, [&]() { return v.determinePos(noPos); });
switch (v.type()) {
case nInt:
str << ANSI_CYAN << v.integer << ANSI_NORMAL;
break;
case nBool:
str << ANSI_CYAN << (v.boolean ? "true" : "false") << ANSI_NORMAL;
break;
case nString:
str << ANSI_WARNING;
printStringValue(str, v.string.s);
str << ANSI_NORMAL;
break;
case nPath:
str << ANSI_GREEN << v.path << ANSI_NORMAL; // !!! escaping?
break;
case nNull:
str << ANSI_CYAN "null" ANSI_NORMAL;
break;
case nAttrs: {
seen.insert(&v);
bool isDrv = state->isDerivation(v);
if (isDrv) {
str << "«derivation ";
Bindings::iterator i = v.attrs->find(state->sDrvPath);
PathSet context;
if (i != v.attrs->end())
str << state->store->printStorePath(state->coerceToStorePath(i->pos, *i->value, context, "while evaluating the drvPath of a derivation"));
else
str << "???";
str << "»";
}
else if (maxDepth > 0) {
str << "{ ";
typedef std::map<std::string, Value *> Sorted;
Sorted sorted;
for (auto & i : *v.attrs)
sorted.emplace(state->symbols[i.name], i.value);
for (auto & i : sorted) {
if (isVarName(i.first))
str << i.first;
else
printStringValue(str, i.first.c_str());
str << " = ";
if (seen.count(i.second))
str << "«repeated»";
else
try {
printValue(str, *i.second, maxDepth - 1, seen);
} catch (AssertionError & e) {
str << ANSI_RED "«error: " << e.msg() << "»" ANSI_NORMAL;
}
str << "; ";
}
str << "}";
} else
str << "{ ... }";
break;
}
case nList:
seen.insert(&v);
str << "[ ";
if (maxDepth > 0)
for (auto elem : v.listItems()) {
if (seen.count(elem))
str << "«repeated»";
else
try {
printValue(str, *elem, maxDepth - 1, seen);
} catch (AssertionError & e) {
str << ANSI_RED "«error: " << e.msg() << "»" ANSI_NORMAL;
}
str << " ";
}
else
str << "... ";
str << "]";
break;
case nFunction:
if (v.isLambda()) {
std::ostringstream s;
s << state->positions[v.lambda.fun->pos];
str << ANSI_BLUE "«lambda @ " << filterANSIEscapes(s.str()) << "»" ANSI_NORMAL;
} else if (v.isPrimOp()) {
str << ANSI_MAGENTA "«primop»" ANSI_NORMAL;
} else if (v.isPrimOpApp()) {
str << ANSI_BLUE "«primop-app»" ANSI_NORMAL;
} else {
abort();
}
break;
case nFloat:
str << v.fpoint;
break;
default:
str << ANSI_RED "«unknown»" ANSI_NORMAL;
break;
}
return str;
}
void runRepl(
ref<EvalState>evalState,
const ValMap & extraEnv)
{
auto getValues = [&]()->NixRepl::AnnotatedValues{
NixRepl::AnnotatedValues values;
return values;
};
const Strings & searchPath = {};
auto repl = std::make_unique<NixRepl>(
searchPath,
openStore(),
evalState,
getValues
);
repl->initEnv();
// add 'extra' vars.
for (auto & [name, value] : extraEnv)
repl->addVarToScope(repl->state->symbols.create(name), *value);
repl->mainLoop();
}
struct CmdRepl : InstallablesCommand
{
CmdRepl() {
evalSettings.pureEval = false;
}
void prepare() override
{
if (!settings.isExperimentalFeatureEnabled(Xp::ReplFlake) && !(file) && this->_installables.size() >= 1) {
warn("future versions of Nix will require using `--file` to load a file");
if (this->_installables.size() > 1)
warn("more than one input file is not currently supported");
auto filePath = this->_installables[0].data();
file = std::optional(filePath);
_installables.front() = _installables.back();
_installables.pop_back();
}
installables = InstallablesCommand::load();
}
std::vector<std::string> files;
Strings getDefaultFlakeAttrPaths() override
{
return {""};
}
bool useDefaultInstallables() override
{
return file.has_value() or expr.has_value();
}
bool forceImpureByDefault() override
{
return true;
}
std::string description() override
{
return "start an interactive environment for evaluating Nix expressions";
}
std::string doc() override
{
return
#include "repl.md"
;
}
void run(ref<Store> store) override
{
auto state = getEvalState();
auto getValues = [&]()->NixRepl::AnnotatedValues{
auto installables = load();
NixRepl::AnnotatedValues values;
for (auto & installable: installables){
auto what = installable->what();
if (file){
auto [val, pos] = installable->toValue(*state);
auto what = installable->what();
state->forceValue(*val, pos);
auto autoArgs = getAutoArgs(*state);
auto valPost = state->allocValue();
state->autoCallFunction(*autoArgs, *val, *valPost);
state->forceValue(*valPost, pos);
values.push_back( {valPost, what });
} else {
auto [val, pos] = installable->toValue(*state);
values.push_back( {val, what} );
}
}
return values;
};
auto repl = std::make_unique<NixRepl>(
searchPath,
openStore(),
state,
getValues
);
repl->autoArgs = getAutoArgs(*repl->state);
repl->initEnv();
repl->mainLoop();
}
};
static auto rCmdRepl = registerCommand<CmdRepl>("repl");
}
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