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pegjs/bin/pegjs-main.js

156 lines
3.3 KiB
JavaScript

importPackage(java.io);
importPackage(java.lang);
/*
* Rhino does not have __FILE__ or anything similar so we have to pass the
* script path from the outside.
*/
load(arguments[0] + "/../lib/peg.js");
var FILE_STDIN = "-";
var FILE_STDOUT = "-";
function readFile(file) {
var f = new BufferedReader(new InputStreamReader(
file === FILE_STDIN ? System["in"] : new FileInputStream(file)
));
var result = "";
var line = "";
try {
while ((line = f.readLine()) !== null) {
result += line + "\n";
}
} finally {
f.close();
}
return result;
}
function writeFile(file, text) {
var f = new BufferedWriter(new OutputStreamWriter(
file === FILE_STDOUT ? System.out : new FileOutputStream(file)
));
try {
f.write(text);
} finally {
f.close();
}
}
function isOption(arg) {
return /-.+/.test(arg);
}
function printVersion() {
print("PEG.js 0.1");
}
function printHelp() {
print("Usage: pegjs [options] [--] <parser_var> [<input_file>] [<output_file>]");
print("");
print("Generates a parser from the PEG grammar specified in the <input_file> and");
print("writes it to the <output_file>.");
print("");
print("If the <output_file> is omitted, its name is generated by changing the");
print("<input_file> extension to \".js\". If both <input_file> and <output_file> are");
print("omitted, standard input and output are used.");
print("");
print("Options:");
print(" -e, --export-var <variable> name of the variable where the parser object");
print(" will be stored (default: \"exports.parser\")");
print(" -v, --version print version information and exit");
print(" -h, --help print help and exit");
}
function nextArg() {
args.shift();
}
function exitSuccess() {
quit(0);
}
function exitFailure() {
quit(1);
}
function abort(message) {
System.out.println(message);
exitFailure();
}
/* This makes the generated parser a CommonJS module by default. */
var exportVar = "exports.parser";
/*
* The trimmed first argument is the script path -- see the beginning of this
* file.
*/
var args = Array.prototype.slice.call(arguments, 1);
while (args.length > 0 && isOption(args[0])) {
switch (args[0]) {
case "-e":
case "--export-var":
nextArg();
exportVar = args[0];
break;
case "--version":
printVersion();
exitSuccess();
break;
case "-v":
case "--version":
printVersion();
exitSuccess();
break;
case "-h":
case "--help":
printHelp();
exitSuccess();
break;
case "--":
nextArg();
break;
default:
abort("Unknown option: " + args[0] + ".");
}
nextArg();
}
switch (args.length) {
case 0:
var inputFile = FILE_STDIN;
var outputFile = FILE_STDOUT;
break;
case 1:
var inputFile = args[0];
var outputFile = args[0].replace(/\.[^.]*$/, ".js");
break;
case 2:
var inputFile = args[0];
var outputFile = args[1];
break;
default:
abort("Too many arguments.");
}
var input = readFile(inputFile);
try {
var parser = PEG.buildParser(input);
} catch (e) {
if (e.line !== undefined && e.column !== undefined) {
abort(e.line + ":" + e.column + ": " + e.message);
} else {
abort(e.message);
}
}
writeFile(outputFile, exportVar + " = " + parser.toSource() + ";\n");