public static Pair expand(VM vm, ArcObject body, Map[] lexicalBindings) {
List result = new LinkedList();
while (!(body instanceof Nil) && body instanceof Pair) {
ArcObject next = body.car();
body = body.cdr();
result.add(Compiler.compile(vm, next, lexicalBindings).reduce());
}
return (Pair) Pair.buildFrom(result, Compiler.compile(vm, body, lexicalBindings).reduce());
}
private static ArcObject replaceBoundSymbols(
Map<Symbol, Integer> lexicalBindings, ArcObject expr, int nesting) {
if (isUnQuote(expr)) {
if (nesting == 1) {
return Pair.buildFrom(UNQUOTE, expr.cdr().car().replaceBoundSymbols(lexicalBindings));
} else {
return Pair.buildFrom(
UNQUOTE, replaceBoundSymbols(lexicalBindings, expr.cdr().car(), nesting - 1));
}
} else if (isUnQuoteSplicing(expr)) {
if (nesting == 1) {
return Pair.buildFrom(
UNQUOTE_SPLICING, expr.cdr().car().replaceBoundSymbols(lexicalBindings));
} else {
return Pair.buildFrom(
UNQUOTE_SPLICING, replaceBoundSymbols(lexicalBindings, expr.cdr().car(), nesting - 1));
}
} else if (isQuasiQuote(expr)) {
return Pair.buildFrom(
QUASIQUOTE, replaceBoundSymbols(lexicalBindings, expr.cdr().car(), nesting + 1));
} else if (expr.isNotPair()) {
return expr;
}
List list = new ArrayList();
ArcObject last = NIL;
while (!expr.isNotPair()) {
if (isUnQuote(expr) || isQuasiQuote(expr)) { // catch post-dot unquotes
last = replaceBoundSymbols(lexicalBindings, expr, nesting);
expr = expr.cdr().cdr();
} else {
final ArcObject current = expr.car();
expr = expr.cdr();
if (isUnQuoteSplicing(current)
|| isUnQuote(current)
|| isQuasiQuote(current)
|| isPair(current)) {
list.add(replaceBoundSymbols(lexicalBindings, current, nesting));
} else {
list.add(current);
}
}
}
if (!(expr instanceof Nil)) {
last = expr;
}
return Pair.buildFrom(list, last);
}
private static ArcObject inline(
StackSymbol p, ArcObject arg, int paramIndex, ArcObject expr, int nesting) {
if (isUnQuote(expr)) {
if (nesting == 1) {
return Pair.buildFrom(UNQUOTE, expr.cdr().car().inline(p, arg, paramIndex));
} else {
return Pair.buildFrom(UNQUOTE, inline(p, arg, paramIndex, expr.cdr().car(), nesting - 1));
}
} else if (isUnQuoteSplicing(expr)) {
if (nesting == 1) {
return Pair.buildFrom(UNQUOTE_SPLICING, expr.cdr().car().inline(p, arg, paramIndex));
} else {
return Pair.buildFrom(
UNQUOTE_SPLICING, inline(p, arg, paramIndex, expr.cdr().car(), nesting - 1));
}
} else if (isQuasiQuote(expr)) {
return Pair.buildFrom(QUASIQUOTE, inline(p, arg, paramIndex, expr.cdr().car(), nesting + 1));
} else if (expr.isNotPair()) {
return expr;
}
List list = new ArrayList();
ArcObject last = NIL;
while (!expr.isNotPair()) {
if (isUnQuote(expr) || isQuasiQuote(expr)) { // catch post-dot unquotes
last = inline(p, arg, paramIndex, expr, nesting);
expr = expr.cdr().cdr();
} else {
final ArcObject current = expr.car();
expr = expr.cdr();
if (isUnQuoteSplicing(current)) {
list.add(inline(p, arg, paramIndex, current, nesting));
} else if (isUnQuote(current) || isQuasiQuote(current) || isPair(current)) {
list.add(inline(p, arg, paramIndex, current, nesting));
} else {
list.add(current);
}
}
}
if (!(expr instanceof Nil)) {
last = expr;
}
return Pair.buildFrom(list, last);
}