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#include <iostream>
#include <cstdlib>
#include <setjmp.h>
#include <readline/readline.h>
#include <readline/history.h>
#include "shared.hh"
#include "eval.hh"
#include "eval-inline.hh"
#include "store-api.hh"
#include "common-opts.hh"
#include "get-drvs.hh"
#include "derivations.hh"
using namespace std;
using namespace nix;
string programId = "nix-repl";
struct NixRepl
{
string curDir;
EvalState state;
StaticEnv staticEnv;
Env * env;
int displ;
NixRepl();
void mainLoop();
void processLine(string line);
void addAttrsToScope(Value & attrs);
void addVarToScope(const Symbol & name, Value * v);
Expr * parseString(string s);
void evalString(string s, Value & v);
};
void printHelp()
{
std::cout << "Usage: nix-repl\n";
}
/* Apparently, the only way to get readline() to return on Ctrl-C
(SIGINT) is to use siglongjmp(). That's fucked up... */
static sigjmp_buf sigintJmpBuf;
static void sigintHandler(int signo)
{
siglongjmp(sigintJmpBuf, 1);
}
bool getLine(string & line)
{
struct sigaction act, old;
act.sa_handler = sigintHandler;
sigfillset(&act.sa_mask);
act.sa_flags = 0;
if (sigaction(SIGINT, &act, &old))
throw SysError("installing handler for SIGINT");
if (sigsetjmp(sigintJmpBuf, 1))
line = "";
else {
char * s = readline("nix-repl> ");
if (!s) return false;
line = chomp(string(s));
free(s);
if (line != "") {
add_history(line.c_str());
append_history(1, 0);
}
}
_isInterrupted = 0;
if (sigaction(SIGINT, &old, 0))
throw SysError("restoring handler for SIGINT");
return true;
}
string removeWhitespace(string s)
{
s = chomp(s);
size_t n = s.find_first_not_of(" \n\r\t");
if (n != string::npos) s = string(s, n);
return s;
}
NixRepl::NixRepl()
: staticEnv(false, &state.staticBaseEnv)
{
curDir = absPath(".");
env = &state.allocEnv(32768);
env->up = &state.baseEnv;
displ = 0;
store = openStore();
}
void NixRepl::mainLoop()
{
std::cerr << "Welcome to Nix version " << NIX_VERSION << ". Type :? for help." << std::endl << std::endl;
using_history();
read_history(0);
while (true) {
string line;
if (!getLine(line)) break;
try {
processLine(removeWhitespace(line));
} catch (Error & e) {
printMsg(lvlError, "error: " + e.msg());
} catch (Interrupted & e) {
printMsg(lvlError, "error: " + e.msg());
}
std::cout << std::endl;
}
std::cout << std::endl;
}
void NixRepl::processLine(string line)
{
if (line == "") return;
string command = string(line, 0, 2);
if (command == ":a") {
Value v;
evalString(string(line, 2), v);
addAttrsToScope(v);
}
else if (command == ":l") {
state.resetFileCache();
Path path = lookupFileArg(state, removeWhitespace(string(line, 2)));
Value v, v2;
state.evalFile(path, v);
Bindings bindings;
state.autoCallFunction(bindings, v, v2);
addAttrsToScope(v2);
}
else if (command == ":t") {
Value v;
evalString(string(line, 2), v);
std::cout << showType(v) << std::endl;
}
else if (command == ":b" || command == ":s") {
Value v;
evalString(string(line, 2), v);
DrvInfo drvInfo;
if (!getDerivation(state, v, drvInfo, false))
throw Error("expression does not evaluation to a derivation, so I can't build it");
Path drvPath = drvInfo.queryDrvPath(state);
if (drvPath == "" || !store->isValidPath(drvPath))
throw Error("expression did not evaluate to a valid derivation");
if (command == ":b") {
/* We could do the build in this process using buildPaths(),
but doing it in a child makes it easier to recover from
problems / SIGINT. */
if (system(("nix-store -r " + drvPath + " > /dev/null").c_str()) == -1)
throw SysError("starting nix-store");
Derivation drv = parseDerivation(readFile(drvPath));
std::cout << "this derivation produced the following outputs:" << std::endl;
foreach (DerivationOutputs::iterator, i, drv.outputs)
std::cout << format(" %1% -> %2%") % i->first % i->second.path << std::endl;
} else {
if (system(("nix-shell " + drvPath).c_str()) == -1)
throw SysError("starting nix-shell");
}
}
else if (string(line, 0, 1) == ":")
throw Error(format("unknown command ‘%1%’") % string(line, 0, 2));
else {
Value v;
evalString(line, v);
state.strictForceValue(v);
std::cout << v << std::endl;
}
}
void NixRepl::addAttrsToScope(Value & attrs)
{
state.forceAttrs(attrs);
foreach (Bindings::iterator, i, *attrs.attrs)
addVarToScope(i->name, i->value);
std::cout << format("added %1% variables") % attrs.attrs->size() << std::endl;
}
void NixRepl::addVarToScope(const Symbol & name, Value * v)
{
staticEnv.vars[name] = displ;
env->values[displ++] = v;
}
Expr * NixRepl::parseString(string s)
{
Expr * e = state.parseExprFromString(s, curDir, staticEnv);
return e;
}
void NixRepl::evalString(string s, Value & v)
{
Expr * e = parseString(s);
e->eval(state, *env, v);
state.forceValue(v);
}
void run(nix::Strings args)
{
NixRepl repl;
repl.mainLoop();
}
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