// (C) Copyright 2001 Samuele Pedroni
package org.python.compiler;
import org.python.antlr.ParseException;
import org.python.antlr.ast.ImportFrom;
import org.python.antlr.ast.Expr;
import org.python.antlr.ast.Interactive;
import org.python.antlr.ast.Module;
import org.python.antlr.ast.Str;
import org.python.antlr.ast.alias;
import org.python.antlr.base.mod;
import org.python.antlr.base.stmt;
import org.python.core.CodeFlag;
import org.python.core.FutureFeature;
import org.python.core.Pragma;
import org.python.core.PragmaReceiver;
import java.util.EnumSet;
import java.util.List;
import java.util.Set;
public class Future {
Set<FutureFeature> featureSet = EnumSet.noneOf(FutureFeature.class);
private final PragmaReceiver features = new PragmaReceiver() {
public void add(Pragma pragma) {
if (pragma instanceof FutureFeature) {
FutureFeature feature = (FutureFeature) pragma;
featureSet.add(feature);
}
}
};
private boolean check(ImportFrom cand) throws Exception {
if (!cand.getInternalModule().equals(FutureFeature.MODULE_NAME))
return false;
if (cand.getInternalNames().isEmpty()) {
throw new ParseException(
"future statement does not support import *", cand);
}
try {
for (alias feature : cand.getInternalNames()) {
// *known* features
FutureFeature.addFeature(feature.getInternalName(), features);
}
} catch (ParseException pe) {
throw new ParseException(pe.getMessage(), cand);
}
return true;
}
public void preprocessFutures(mod node, org.python.core.CompilerFlags cflags)
throws Exception {
if (cflags != null) {
if (cflags.isFlagSet(CodeFlag.CO_FUTURE_DIVISION))
FutureFeature.division.addTo(features);
if (cflags.isFlagSet(CodeFlag.CO_FUTURE_WITH_STATEMENT))
FutureFeature.with_statement.addTo(features);
if (cflags.isFlagSet(CodeFlag.CO_FUTURE_ABSOLUTE_IMPORT))
FutureFeature.absolute_import.addTo(features);
}
int beg = 0;
List<stmt> suite = null;
if (node instanceof Module) {
suite = ((Module) node).getInternalBody();
if (suite.size() > 0 && suite.get(0) instanceof Expr
&& ((Expr) suite.get(0)).getInternalValue() instanceof Str) {
beg++;
}
} else if (node instanceof Interactive) {
suite = ((Interactive) node).getInternalBody();
} else {
return;
}
for (int i = beg; i < suite.size(); i++) {
stmt s = suite.get(i);
if (!(s instanceof ImportFrom)) break;
s.from_future_checked = true;
if (!check((ImportFrom) s)) break;
}
if (cflags != null) {
for (FutureFeature feature : featureSet) {
feature.setFlag(cflags);
}
}
}
public static void checkFromFuture(ImportFrom node) throws Exception {
if (node.from_future_checked) return;
if (node.getInternalModule().equals(FutureFeature.MODULE_NAME)) {
throw new ParseException("from __future__ imports must occur "
+ "at the beginning of the file", node);
}
node.from_future_checked = true;
}
public boolean areDivisionOn() {
return featureSet.contains(FutureFeature.division);
}
public boolean withStatementSupported() {
return featureSet.contains(FutureFeature.with_statement);
}
public boolean isAbsoluteImportOn() {
return featureSet.contains(FutureFeature.absolute_import);
}
}