forked from lix-project/lix
287c88ca59
The command ":a <expr>" evaluates <expr> and adds the attributes in
the resulting attribute set to the interpreter scope. For instance:
nix-repl> :a import <nixpkgs> {}
nix-repl> lib.range 0 10
[ 0 1 2 3 4 5 6 7 8 9 10 ]
135 lines
2.4 KiB
C++
135 lines
2.4 KiB
C++
#include <iostream>
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#include <cstdlib>
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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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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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NixRepl();
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void mainLoop();
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void processLine(string line);
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void addVar(const Symbol & name, Value * v);
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Expr * parseString(string s);
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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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bool getLine(string & line)
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{
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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 != "") add_history(line.c_str());
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return true;
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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()
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{
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std::cerr << "Welcome to Nix version " << NIX_VERSION << ". Type :? for help." << std::endl << std::endl;
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while (true) {
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string line;
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if (!getLine(line)) break;
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/* Remove preceeding whitespace. */
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size_t n = line.find_first_not_of(" \n\r\t");
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if (n != string::npos) line = string(line, n);
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try {
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processLine(line);
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} catch (Error & e) {
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printMsg(lvlError, 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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void NixRepl::processLine(string line)
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{
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if (string(line, 0, 2) == ":a") {
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Expr * e = parseString(string(line, 2));
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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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addVar(i->name, i->value);
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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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}
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else {
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Expr * e = parseString(line);
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Value v;
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e->eval(state, *env, 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::addVar(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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}
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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 run(nix::Strings args)
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{
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NixRepl repl;
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repl.mainLoop();
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}
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