/** Desugar a generalized While clause. */
@Override
public Node forWhile(While w) {
GeneratorClause g = w.getTestExpr();
if (g.getBind().size() > 0) {
// while binds <- expr do body end
// desugars to
// while __whileCond(expr, fn (binds) => body) do end
ArrayList<Expr> args = new ArrayList<Expr>(2);
args.add(g.getInit());
args.add(bindsAndBody(g, w.getBody()));
Expr cond =
ExprFactory.make_RewriteFnApp(
NodeUtil.getSpan(g),
WHILECOND_NAME,
ExprFactory.makeTupleExpr(NodeUtil.getSpan(w), args));
w = ExprFactory.makeWhile(NodeUtil.getSpan(w), cond);
}
return (Expr) super.forWhile(w);
}
/**
* Add an if clause to a (potentially) pre-existing else clause. The else clase can be null, or
* can be an if expression.
*/
private Expr addIfClause(IfClause c, Expr elsePart) {
GeneratorClause g = c.getTestClause();
if (g.getBind().size() > 0) {
// if binds <- expr then body else elsePart end desugars to
// __cond(expr, fn (binds) => body, elsePart)
ArrayList<Expr> args = new ArrayList<Expr>(3);
args.add(g.getInit());
args.add(bindsAndBody(g, c.getBody()));
if (elsePart != null) args.add(thunk(elsePart));
return (Expr)
recur(
ExprFactory.make_RewriteFnApp(
NodeUtil.getSpan(c),
COND_NAME,
ExprFactory.makeTupleExpr(NodeUtil.getSpan(c), args)));
}
// if expr then body else elsePart end is preserved
// (but we replace elif chains by nesting).
if (elsePart == null) {
return (Expr) super.forIf(ExprFactory.makeIf(NodeUtil.getSpan(c), c));
} else {
return (Expr)
super.forIf(ExprFactory.makeIf(NodeUtil.getSpan(c), c, ExprFactory.makeBlock(elsePart)));
}
}
/**
* @param loc Containing context
* @param gens Generators in generator list
* @return single generator equivalent to the generator list Desugars as follows: body, empty =>
* body body, x <- exp, gs => exp.loop(fn x => body, gs)
*/
Expr visitLoop(Span span, List<GeneratorClause> gens, Expr body) {
for (int i = gens.size() - 1; i >= 0; i--) {
GeneratorClause g = gens.get(i);
Expr loopBody = bindsAndBody(g, body);
body =
ExprFactory.makeMethodInvocation(NodeUtil.getSpan(g), g.getInit(), LOOP_NAME, loopBody);
}
// System.out.println("Desugared to "+body.toStringVerbose());
return (Expr) recur(body);
}
