/**
* Create an AST from a program (using ANTLR lexer & parser) Returns null if error Use
* 'alreadyIncluded' to keep track of from 'include' statements
*/
public static ParseTree createAst(File file, boolean debug, Set<String> alreadyIncluded) {
alreadyIncluded.add(Gpr.getCanonicalFileName(file));
String fileName = file.toString();
String filePath = fileName;
BigDataScriptLexer lexer = null;
BigDataScriptParser parser = null;
try {
filePath = file.getCanonicalPath();
// Input stream
if (!Gpr.canRead(filePath)) {
CompilerMessages.get().addError("Can't read file '" + filePath + "'");
return null;
}
// Create a CharStream that reads from standard input
ANTLRFileStream input = new ANTLRFileStream(fileName);
// ---
// Lexer: Create a lexer that feeds off of input CharStream
// ---
lexer =
new BigDataScriptLexer(input) {
@Override
public void recover(LexerNoViableAltException e) {
throw new RuntimeException(e); // Bail out
}
};
// ---
// Parser
// ---
CommonTokenStream tokens = new CommonTokenStream(lexer);
parser = new BigDataScriptParser(tokens);
// Parser error handling
parser.setErrorHandler(
new CompileErrorStrategy()); // Bail out with exception if errors in parser
parser.addErrorListener(new CompilerErrorListener()); // Catch some other error messages that
// 'CompileErrorStrategy' fails to catch
// Begin parsing at main rule
ParseTree tree = parser.programUnit();
// Error loading file?
if (tree == null) {
System.err.println("Can't parse file '" + filePath + "'");
return null;
}
// Show main nodes
if (debug) {
Timer.showStdErr("AST:");
for (int childNum = 0; childNum < tree.getChildCount(); childNum++) {
Tree child = tree.getChild(childNum);
System.err.println(
"\t\tChild " + childNum + ":\t" + child + "\tTree:'" + child.toStringTree() + "'");
}
}
// Included files
boolean resolveIncludePending = true;
while (resolveIncludePending)
resolveIncludePending = resolveIncludes(tree, debug, alreadyIncluded);
return tree;
} catch (Exception e) {
String msg = e.getMessage();
CompilerMessages.get()
.addError(
"Could not compile "
+ filePath //
+ (msg != null ? " :" + e.getMessage() : "") //
);
return null;
}
}
