forked from lix-project/lix
593 lines
15 KiB
C++
593 lines
15 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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Strings loadedFiles;
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const static int envSize = 32768;
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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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bool processLine(string line);
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void loadFile(const Path & path);
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void initEnv();
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void reloadFiles();
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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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typedef set<Value *> ValuesSeen;
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std::ostream & printValue(std::ostream & str, Value & v, unsigned int maxDepth);
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std::ostream & printValue(std::ostream & str, Value & v, unsigned int maxDepth, ValuesSeen & seen);
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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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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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loadedFiles.push_back(*i);
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reloadFiles();
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if (!loadedFiles.empty()) std::cout << std::endl;
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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)) {
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std::cout << std::endl;
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break;
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}
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try {
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if (!processLine(removeWhitespace(line))) return;
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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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}
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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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size_t dot = prefix.rfind('.');
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if (dot == string::npos) {
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/* This is a variable name; look it up in the current scope. */
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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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} else {
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try {
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/* This is an expression that should evaluate to an
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attribute set. Evaluate it to get the names of the
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attributes. */
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string expr(prefix, 0, dot);
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string prefix2 = string(prefix, dot + 1);
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Expr * e = parseString(expr);
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Value v;
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e->eval(state, *env, v);
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state.forceAttrs(v);
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foreach (Bindings::iterator, i, *v.attrs) {
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string name = i->name;
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if (string(name, 0, prefix2.size()) != prefix2) continue;
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completions.insert(expr + "." + name);
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}
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} catch (ParseError & e) {
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// Quietly ignore parse errors.
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}catch (EvalError & e) {
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// Quietly ignore evaluation errors.
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}
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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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bool isVarName(const string & s)
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{
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// FIXME: not quite correct.
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foreach (string::const_iterator, i, s)
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if (!((*i >= 'a' && *i <= 'z') ||
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(*i >= 'A' && *i <= 'Z') ||
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(*i >= '0' && *i <= '9') ||
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*i == '_' || *i == '\''))
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return false;
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return true;
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}
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bool NixRepl::processLine(string line)
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{
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if (line == "") return true;
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string command, arg;
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if (line[0] == ':') {
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size_t p = line.find(' ');
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command = string(line, 0, p);
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if (p != string::npos) arg = removeWhitespace(string(line, p));
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} else {
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arg = line;
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}
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if (command == ":?" || command == ":help") {
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cout << "The following commands are available:\n"
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<< "\n"
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<< " <expr> Evaluate and print expression\n"
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<< " <x> = <expr> Bind expression to variable\n"
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<< " :a <expr> Add attributes from resulting set to scope\n"
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<< " :b <expr> Build derivation\n"
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<< " :l <path> Load Nix expression and add it to scope\n"
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<< " :p <expr> Evaluate and print expression recursively\n"
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<< " :q Exit nix-repl\n"
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<< " :r Reload all files\n"
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<< " :s <expr> Build dependencies of derivation, then start nix-shell\n"
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<< " :t <expr> Describe result of evaluation\n";
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}
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else if (command == ":a" || command == ":add") {
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Value v;
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evalString(arg, v);
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addAttrsToScope(v);
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}
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else if (command == ":l" || command == ":load") {
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state.resetFileCache();
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loadFile(arg);
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}
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else if (command == ":r" || command == ":reload") {
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state.resetFileCache();
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reloadFiles();
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}
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else if (command == ":t") {
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Value v;
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evalString(arg, 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(arg, 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) {
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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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}
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} else
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runProgram("nix-shell", Strings{drvPath});
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}
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else if (command == ":p" || command == ":print") {
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Value v;
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evalString(arg, v);
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printValue(std::cout, v, 1000000000) << std::endl;
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}
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else if (command == ":q" || command == ":quit")
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return false;
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else if (command != "")
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throw Error(format("unknown command ‘%1%’") % command);
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else {
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size_t p = line.find('=');
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string name;
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if (p != string::npos &&
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isVarName(name = removeWhitespace(string(line, 0, p))))
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{
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Expr * e = parseString(string(line, p + 1));
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Value & v(*state.allocValue());
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v.type = tThunk;
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v.thunk.env = env;
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v.thunk.expr = e;
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addVarToScope(state.symbols.create(name), v);
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} else {
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Value v;
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evalString(line, v);
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printValue(std::cout, v, 1) << std::endl;
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}
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}
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return true;
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}
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void NixRepl::loadFile(const Path & path)
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{
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loadedFiles.remove(path);
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loadedFiles.push_back(path);
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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::initEnv()
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{
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env = &state.allocEnv(envSize);
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env->up = &state.baseEnv;
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displ = 0;
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staticEnv.vars.clear();
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varNames.clear();
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foreach (StaticEnv::Vars::iterator, i, state.staticBaseEnv.vars)
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varNames.insert(i->first);
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}
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void NixRepl::reloadFiles()
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{
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initEnv();
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Strings old = loadedFiles;
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loadedFiles.clear();
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foreach (Strings::iterator, i, old) {
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if (i != old.begin()) std::cout << std::endl;
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std::cout << format("Loading ‘%1%’...") % *i << std::endl;
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loadFile(*i);
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}
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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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if (displ >= envSize)
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throw Error("environment full; cannot add more variables");
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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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std::ostream & NixRepl::printValue(std::ostream & str, Value & v, unsigned int maxDepth)
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{
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ValuesSeen seen;
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return printValue(str, v, maxDepth, seen);
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}
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// FIXME: lot of cut&paste from Nix's eval.cc.
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std::ostream & NixRepl::printValue(std::ostream & str, Value & v, unsigned int maxDepth, ValuesSeen & seen)
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{
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str.flush();
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checkInterrupt();
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state.forceValue(v);
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switch (v.type) {
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case tInt:
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str << v.integer;
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break;
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case tBool:
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str << (v.boolean ? "true" : "false");
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break;
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case tString:
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str << "\"";
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for (const char * i = v.string.s; *i; i++)
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if (*i == '\"' || *i == '\\') str << "\\" << *i;
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else if (*i == '\n') str << "\\n";
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else if (*i == '\r') str << "\\r";
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else if (*i == '\t') str << "\\t";
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else str << *i;
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str << "\"";
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break;
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case tPath:
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str << v.path; // !!! escaping?
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break;
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case tNull:
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str << "null";
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break;
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case tAttrs: {
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seen.insert(&v);
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bool isDrv = state.isDerivation(v);
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if (isDrv) {
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str << "«derivation ";
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Bindings::iterator i = v.attrs->find(state.sDrvPath);
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PathSet context;
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Path drvPath = i != v.attrs->end() ? state.coerceToPath(*i->value, context) : "???";
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str << drvPath << "»";
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}
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else if (maxDepth > 0) {
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str << "{ ";
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typedef std::map<string, Value *> Sorted;
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Sorted sorted;
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foreach (Bindings::iterator, i, *v.attrs)
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sorted[i->name] = i->value;
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/* If this is a derivation, then don't show the
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self-references ("all", "out", etc.). */
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StringSet hidden;
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if (isDrv) {
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hidden.insert("all");
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Bindings::iterator i = v.attrs->find(state.sOutputs);
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if (i == v.attrs->end())
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hidden.insert("out");
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else {
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state.forceList(*i->value);
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for (unsigned int j = 0; j < i->value->list.length; ++j)
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hidden.insert(state.forceStringNoCtx(*i->value->list.elems[j]));
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}
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}
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foreach (Sorted::iterator, i, sorted) {
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str << i->first << " = ";
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if (hidden.find(i->first) != hidden.end())
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str << "«...»";
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else if (seen.find(i->second) != seen.end())
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str << "«repeated»";
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else
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try {
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printValue(str, *i->second, maxDepth - 1, seen);
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} catch (AssertionError & e) {
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str << "«error: " << e.msg() << "»";
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}
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str << "; ";
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}
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str << "}";
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} else
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str << "{ ... }";
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break;
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}
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case tList:
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seen.insert(&v);
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str << "[ ";
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if (maxDepth > 0)
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for (unsigned int n = 0; n < v.list.length; ++n) {
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if (seen.find(v.list.elems[n]) != seen.end())
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str << "«repeated»";
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else
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try {
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printValue(str, *v.list.elems[n], maxDepth - 1, seen);
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} catch (AssertionError & e) {
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str << "«error: " << e.msg() << "»";
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}
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str << " ";
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}
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else
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str << "... ";
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str << "]";
|
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break;
|
||
|
||
case tLambda:
|
||
str << "«lambda»";
|
||
break;
|
||
|
||
case tPrimOp:
|
||
str << "«primop»";
|
||
break;
|
||
|
||
case tPrimOpApp:
|
||
str << "«primop-app»";
|
||
break;
|
||
|
||
default:
|
||
str << "«unknown»";
|
||
break;
|
||
}
|
||
|
||
return str;
|
||
}
|
||
|
||
|
||
void run(Strings args)
|
||
{
|
||
NixRepl repl;
|
||
repl.mainLoop(args);
|
||
}
|