public override void Visit(ChainExpr expr)
{
if (ReferencesRootVariableVisitor.ReferencesRootVariable(expr))
{
_needsAsync = true;
return;
}
// Some things can't be simplified by themselves, but they can be in the
// context of a chain. If this chain doesn't need to be asynchronous, then
// the next key or index won't need it either.
if (NeedsAsyncByItselfVisitor.NeedsAsyncByItself(expr.Next))
{
_needsAsync = true;
return;
}
}
private Expr ParseChainRemainder(Expr prev)
{
var token = GetToken();
Expr first = null;
if (token.Kind == ".")
{
Match(".");
first = ParseKeyExpr(prev);
}
else if (token.Kind == "[?")
{
first = ParseFilterExpr(prev);
}
else if (token.Kind == "[")
{
first = ParseIndexExpr(prev);
}
else if (token.Kind == "(")
{
// Super gross; in retrospect, all expressions should just be self-contained, or this
// should at least work the same as the other chain expressions.
first = ParseIndexedLookup(prev);
}
else if (token.Kind == "{")
{
var map = ParseMapProjectionExpr(null);
first = new ChainExpr(prev, map, ChainBehavior.ToMultipleIfArray);
}
var nextToken = GetToken();
if (nextToken.Kind == "." || nextToken.Kind == "[" || nextToken.Kind == "(" || nextToken.Kind == "{" || nextToken.Kind == "[?")
{
return(ParseChainRemainder(first));
}
else
{
return(first);
}
}
public virtual void Visit(ChainExpr expr)
{
}
private Expr ParseMapProjectionExpr(Expr prev)
{
var bracket = Match("{");
var projections = new List <Expr>();
while (true)
{
var token = GetToken();
if (token.Kind == "}")
{
Match("}");
break;
}
string id = null;
Expr projection;
if (token.Kind == "}")
{
Match("}");
break;
}
if (token.Kind == "...")
{
var ellipsis = Match("...");
var next = GetToken();
projection = new SpreadExpr(GetLocation(ellipsis), ParseExpr());
}
else if (token.Kind == "$")
{
var dollar = Match("$");
var dollarLocation = GetLocation(dollar);
id = Match("ID").Text;
projection = new KeyValuePairExpr(dollarLocation, id, new VariableExpr(dollarLocation, id));
}
else
{
var idToken = MatchAny(new [] { "STRING", "ID" });
var idLocation = GetLocation(idToken);
id = idToken.Text;
var curr = GetToken();
if (curr.Kind == ":")
{
Match(":");
projection = new KeyValuePairExpr(idLocation, id, ParseExpr());
}
else if (curr.Kind == "{")
{
// These are all equivalent:
// foo: foo | { a, b, c }
// foo | { a, b, c }
// foo { a, b, c }
MatchOptional("|");
var rhs = new ChainExpr(
new KeyExpr(idLocation, prev, id),
ParseExpr(),
ChainBehavior.ToMultipleIfArray);
projection = new KeyValuePairExpr(idLocation, id, rhs);
}
else if (curr.Kind == "(")
{
// key(a: 123) => key: key(a:123)
var keyExpr = new KeyExpr(idLocation, prev, id);
var rhs = ParseChainRemainder(keyExpr);
projection = new KeyValuePairExpr(idLocation, id, rhs);
}
else if (curr.Kind == "[?")
{
// x[? filter] => x: x[? filter]
var keyExpr = new KeyExpr(idLocation, prev, id);
var rhs = ParseChainRemainder(keyExpr);
projection = new KeyValuePairExpr(idLocation, id, rhs);
}
else if (curr.Kind == "[")
{
// x[5] => x: x[5]
var keyExpr = new KeyExpr(idLocation, prev, id);
var rhs = ParseChainRemainder(keyExpr);
projection = new KeyValuePairExpr(idLocation, id, rhs);
}
else if (curr.Kind == "|")
{
// These are all equivalent:
// foo: foo | { a, b, c }
// foo | { a, b, c }
// foo { a, b, c }
MatchOptional("|");
var rhs = new ChainExpr(
new KeyExpr(idLocation, prev, id),
ParseExpr(),
ChainBehavior.OneToOne);
projection = new KeyValuePairExpr(idLocation, id, rhs);
}
else if (curr.Kind == "|<")
{
// This is another shorthand for filtring an array of objects. These are equivalent:
/// foo: foo |< { a, b, c }
/// foo |< { a, b, c}
Match("|<");
var rhs = new ChainExpr(
new KeyExpr(idLocation, prev, id),
ParseExpr(),
ChainBehavior.ToMultiple);
projection = new KeyValuePairExpr(idLocation, id, rhs);
}
else
{
projection = new KeyValuePairExpr(idLocation, id, new KeyExpr(idLocation, null, id));
}
}
projections.Add(projection);
var tok = MatchAny(new [] { ",", "}" });
if (tok.Kind == "}")
{
break;
}
}
return(new MapProjectionExpr(GetLocation(bracket), prev, projections));
}