lix-project/lix
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Support multiline input by detecting "unfinished" parse errors.

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Fixes #4,
This commit is contained in:
Scott Olson 2016-02-18 06:27:39 -06:00
parent dc8b51754b
commit 2d729e4f6f
1 changed files with 23 additions and 5 deletions
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28
nix-repl.cc
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@ -41,7 +41,7 @@ struct NixRepl
NixRepl(const Strings & searchPath);
void mainLoop(const Strings & files);
void completePrefix(string prefix);
bool getLine(string & line);
bool getLine(string & line, const char * prompt);
bool processLine(string line);
void loadFile(const Path & path);
void initEnv();
@ -96,21 +96,39 @@ void NixRepl::mainLoop(const Strings & files)
using_history();
read_history(0);
string input;
while (true) {
// When continuing input from a previous, don't print a prompt, just align to the same
// number of chars as the prompt.
const char * prompt = input.empty() ? "nix-repl> " : " ";
string line;
if (!getLine(line)) {
if (!getLine(line, prompt)) {
std::cout << std::endl;
break;
}
input.append(removeWhitespace(line));
input.push_back('\n');
try {
if (!processLine(removeWhitespace(line))) return;
if (!processLine(input)) return;
} catch (ParseError & e) {
if (e.msg().find("unexpected $end") != 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, "error: " + e.msg());
}
} catch (Error & e) {
printMsg(lvlError, "error: " + e.msg());
} catch (Interrupted & e) {
printMsg(lvlError, "error: " + e.msg());
}
// We handled the current input fully, so we should clear it and read brand new input.
input.clear();
std::cout << std::endl;
}
}
@ -149,7 +167,7 @@ char * completerThunk(const char * s, int state)
}
bool NixRepl::getLine(string & line)
bool NixRepl::getLine(string & line, const char * prompt)
{
struct sigaction act, old;
act.sa_handler = sigintHandler;
@ -164,7 +182,7 @@ bool NixRepl::getLine(string & line)
curRepl = this;
rl_completion_entry_function = completerThunk;
char * s = readline("nix-repl> ");
char * s = readline(prompt);
if (!s) return false;
line = chomp(string(s));
free(s);