public Object visit(If ifStatement) {
Object temp;
temp = ifStatement.getCondition().accept(this);
if (temp != null) return temp;
temp = ifStatement.getOperation().accept(this);
if (temp != null) return temp;
if (ifStatement.hasElse()) {
temp = ifStatement.getElseOperation().accept(this);
if (temp != null) return temp;
}
if (!Type.isBool(ifStatement.getCondition())) {
return ifStatement;
}
return null;
}
/**
* check if every control path has a return value
*
* @throws SemanticError
*/
public boolean hasReturnOnControlPaths(List<Statement> statements) throws SemanticError {
// initialize return value
boolean found = false;
for (Statement stmt : statements) {
if (stmt instanceof Return) {
// in case we found a return statement, set found to true
found = true;
}
if (stmt instanceof StatementsBlock) {
// in case we found a statement block, iterate all statements
found |= hasReturnOnControlPaths(((StatementsBlock) stmt).getStatements());
}
if (stmt instanceof If) {
/*
* in case we found an if statement, iterate recursively the
* 'then' statement and the 'else' statement
*/
If stmtAsIf = (If) stmt;
if (stmtAsIf.getCondition() instanceof Literal) {
Literal cond = (Literal) stmtAsIf.getCondition();
if (cond.getType() == LiteralTypes.TRUE)
found |= hasReturnOnControlPaths(stmtAsIf.getOperation());
else if (cond.getType() == LiteralTypes.FALSE) {
if (stmtAsIf.hasElse())
found |= hasReturnOnControlPaths(((If) stmt).getElseOperation());
} else throw new SemanticError("Unexpected literal in if statement", stmt);
}
found |=
(hasReturnOnControlPaths(stmtAsIf.getOperation())
&& (stmtAsIf.hasElse()
? hasReturnOnControlPaths(stmtAsIf.getElseOperation())
: false));
}
}
return found;
}