forked from lix-project/lix
317 lines
7.4 KiB
C++
317 lines
7.4 KiB
C++
#include <iostream>
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#include <cstdlib>
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#include <setjmp.h>
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#include <readline/readline.h>
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#include <readline/history.h>
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#include "shared.hh"
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#include "eval.hh"
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#include "eval-inline.hh"
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#include "store-api.hh"
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#include "common-opts.hh"
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#include "get-drvs.hh"
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#include "derivations.hh"
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#include "affinity.hh"
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using namespace std;
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using namespace nix;
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string programId = "nix-repl";
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struct NixRepl
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{
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string curDir;
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EvalState state;
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StaticEnv staticEnv;
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Env * env;
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int displ;
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StringSet varNames;
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StringSet completions;
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StringSet::iterator curCompletion;
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NixRepl();
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void mainLoop(const Strings & args);
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void completePrefix(string prefix);
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bool getLine(string & line);
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void processLine(string line);
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void loadFile(const Path & path);
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void addAttrsToScope(Value & attrs);
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void addVarToScope(const Symbol & name, Value * v);
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Expr * parseString(string s);
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void evalString(string s, Value & v);
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};
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void printHelp()
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{
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std::cout << "Usage: nix-repl\n";
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}
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string removeWhitespace(string s)
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{
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s = chomp(s);
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size_t n = s.find_first_not_of(" \n\r\t");
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if (n != string::npos) s = string(s, n);
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return s;
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}
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NixRepl::NixRepl()
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: staticEnv(false, &state.staticBaseEnv)
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{
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curDir = absPath(".");
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env = &state.allocEnv(32768);
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env->up = &state.baseEnv;
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displ = 0;
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store = openStore();
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}
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void NixRepl::mainLoop(const Strings & args)
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{
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std::cout << "Welcome to Nix version " << NIX_VERSION << ". Type :? for help." << std::endl << std::endl;
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foreach (Strings::const_iterator, i, args) {
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std::cout << format("Loading ‘%1%’...") % *i << std::endl;
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loadFile(*i);
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std::cout << std::endl;
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}
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using_history();
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read_history(0);
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while (true) {
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string line;
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if (!getLine(line)) break;
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try {
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processLine(removeWhitespace(line));
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} catch (Error & e) {
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printMsg(lvlError, "error: " + e.msg());
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} catch (Interrupted & e) {
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printMsg(lvlError, "error: " + e.msg());
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}
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std::cout << std::endl;
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}
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std::cout << std::endl;
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}
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/* Apparently, the only way to get readline() to return on Ctrl-C
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(SIGINT) is to use siglongjmp(). That's fucked up... */
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static sigjmp_buf sigintJmpBuf;
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static void sigintHandler(int signo)
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{
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siglongjmp(sigintJmpBuf, 1);
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}
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/* Oh, if only g++ had nested functions... */
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NixRepl * curRepl;
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char * completerThunk(const char * s, int state)
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{
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string prefix(s);
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/* If the prefix has a slash in it, use readline's builtin filename
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completer. */
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if (prefix.find('/') != string::npos)
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return rl_filename_completion_function(s, state);
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/* Otherwise, return all symbols that start with the prefix. */
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if (state == 0) {
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curRepl->completePrefix(s);
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curRepl->curCompletion = curRepl->completions.begin();
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}
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if (curRepl->curCompletion == curRepl->completions.end()) return 0;
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return strdup((curRepl->curCompletion++)->c_str());
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}
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bool NixRepl::getLine(string & line)
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{
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struct sigaction act, old;
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act.sa_handler = sigintHandler;
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sigfillset(&act.sa_mask);
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act.sa_flags = 0;
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if (sigaction(SIGINT, &act, &old))
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throw SysError("installing handler for SIGINT");
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if (sigsetjmp(sigintJmpBuf, 1))
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line = "";
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else {
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curRepl = this;
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rl_completion_entry_function = completerThunk;
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char * s = readline("nix-repl> ");
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if (!s) return false;
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line = chomp(string(s));
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free(s);
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if (line != "") {
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add_history(line.c_str());
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append_history(1, 0);
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}
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}
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_isInterrupted = 0;
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if (sigaction(SIGINT, &old, 0))
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throw SysError("restoring handler for SIGINT");
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return true;
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}
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void NixRepl::completePrefix(string prefix)
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{
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completions.clear();
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StringSet::iterator i = varNames.lower_bound(prefix);
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while (i != varNames.end()) {
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if (string(*i, 0, prefix.size()) != prefix) break;
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completions.insert(*i);
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i++;
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}
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}
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static int runProgram(const string & program, const Strings & args)
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{
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std::vector<const char *> cargs; /* careful with c_str()! */
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cargs.push_back(program.c_str());
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for (Strings::const_iterator i = args.begin(); i != args.end(); ++i)
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cargs.push_back(i->c_str());
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cargs.push_back(0);
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Pid pid;
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pid = fork();
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if (pid == -1) throw SysError("forking");
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if (pid == 0) {
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restoreAffinity();
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execvp(program.c_str(), (char * *) &cargs[0]);
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_exit(1);
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}
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return pid.wait(true);
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}
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void NixRepl::processLine(string line)
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{
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if (line == "") return;
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string command = string(line, 0, 2);
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if (command == ":a") {
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Value v;
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evalString(string(line, 2), v);
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addAttrsToScope(v);
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}
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else if (command == ":l") {
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state.resetFileCache();
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loadFile(removeWhitespace(string(line, 2)));
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}
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else if (command == ":t") {
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Value v;
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evalString(string(line, 2), v);
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std::cout << showType(v) << std::endl;
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}
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else if (command == ":b" || command == ":s") {
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Value v;
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evalString(string(line, 2), v);
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DrvInfo drvInfo;
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if (!getDerivation(state, v, drvInfo, false))
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throw Error("expression does not evaluation to a derivation, so I can't build it");
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Path drvPath = drvInfo.queryDrvPath(state);
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if (drvPath == "" || !store->isValidPath(drvPath))
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throw Error("expression did not evaluate to a valid derivation");
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if (command == ":b") {
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/* We could do the build in this process using buildPaths(),
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but doing it in a child makes it easier to recover from
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problems / SIGINT. */
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if (runProgram("nix-store", Strings{"-r", drvPath}) != 0) return;
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Derivation drv = parseDerivation(readFile(drvPath));
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std::cout << std::endl << "this derivation produced the following outputs:" << std::endl;
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foreach (DerivationOutputs::iterator, i, drv.outputs)
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std::cout << format(" %1% -> %2%") % i->first % i->second.path << std::endl;
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} else
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runProgram("nix-shell", Strings{drvPath});
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}
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else if (string(line, 0, 1) == ":")
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throw Error(format("unknown command ‘%1%’") % string(line, 0, 2));
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else {
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Value v;
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evalString(line, v);
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state.strictForceValue(v);
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std::cout << v << std::endl;
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}
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}
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void NixRepl::loadFile(const Path & path)
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{
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Value v, v2;
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state.evalFile(lookupFileArg(state, path), v);
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Bindings bindings;
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state.autoCallFunction(bindings, v, v2);
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addAttrsToScope(v2);
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}
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void NixRepl::addAttrsToScope(Value & attrs)
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{
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state.forceAttrs(attrs);
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foreach (Bindings::iterator, i, *attrs.attrs)
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addVarToScope(i->name, i->value);
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std::cout << format("Added %1% variables.") % attrs.attrs->size() << std::endl;
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}
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void NixRepl::addVarToScope(const Symbol & name, Value * v)
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{
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staticEnv.vars[name] = displ;
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env->values[displ++] = v;
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varNames.insert((string) name);
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}
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Expr * NixRepl::parseString(string s)
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{
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Expr * e = state.parseExprFromString(s, curDir, staticEnv);
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return e;
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}
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void NixRepl::evalString(string s, Value & v)
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{
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Expr * e = parseString(s);
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e->eval(state, *env, v);
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state.forceValue(v);
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}
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void run(Strings args)
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{
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NixRepl repl;
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repl.mainLoop(args);
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}
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