/** Find stop token index of next operator; return -1 if not operator. */
public static int getLastOpTokenIndex(ITokenStream tokens)
{
var i = tokens.Index; // current on-channel lookahead token index
var lt = tokens.Get(i);
if (lt.getType() == SwiftParser.DOT && tokens.get(i + 1).getType() == SwiftParser.DOT)
{
// dot-operator
i += 2; // point at token after ".."
lt = tokens.get(i);
while (lt.getType() != Token.EOF &&
(lt.getType() == SwiftParser.DOT || isOperatorChar(lt.getType())))
{
i++;
lt = tokens.get(i);
}
return(i - 1);
}
// Is it regular operator?
if (!isOperatorHead(lt.getType()))
{
return(-1);
}
i++;
lt = tokens.get(i);
while (lt.getType() != Token.EOF && isOperatorChar(lt.getType()))
{
i++;
lt = tokens.get(i);
}
int stop = i - 1;
return(stop);
}
/** Return two booleans packed into lowest 2 bits for left (high) and right (low)
* whitespace.
*/
public static int getLeftRightWS(ITokenStream tokens, ParserRuleContext ctx)
{
var left = ctx.start.getTokenIndex();
var right = ctx.stop.getTokenIndex();
var prevToken = tokens.get(left - 1); // includes hidden-channel tokens
var nextToken = tokens.get(right + 1);
var prevIsWS = isLeftOperatorWS(prevToken);
var nextIsWS = isRightOperatorWS(nextToken);
var b = (prevIsWS ? 1 : 0) << 1 | (nextIsWS ? 1 : 0);
return(b);
}
/**
* "If an operator has whitespace on the left side only, it is treated as a
* prefix unary operator. As an example, the ++ operator in a ++b is treated
* as a prefix unary operator."
*/
public static boolean isPrefixOp(ITokenStream tokens)
{
int stop = getLastOpTokenIndex(tokens);
if (stop == -1)
{
return(false);
}
var start = tokens.Index;
var prevToken = tokens.get(start - 1); // includes hidden-channel tokens
var nextToken = tokens.get(stop + 1);
var prevIsWS = isLeftOperatorWS(prevToken);
var nextIsWS = isRightOperatorWS(nextToken);
var result = prevIsWS && !nextIsWS;
var text = tokens.GetText(Interval.Of(start, stop));
//System.out.println("isPrefixOp: '"+prevToken+"','"+text+"','"+nextToken+"' is "+result);
return(result);
}
/** Return two booleans packed into lowest 2 bits for left (high) and right (low)
* whitespace.
*/
public static int getLeftRightWS(ITokenStream tokens, ParserRuleContext ctx) {
var left = ctx.start.getTokenIndex();
var right = ctx.stop.getTokenIndex();
var prevToken = tokens.get(left - 1); // includes hidden-channel tokens
var nextToken = tokens.get(right + 1);
var prevIsWS = isLeftOperatorWS(prevToken);
var nextIsWS = isRightOperatorWS(nextToken);
var b = (prevIsWS ? 1 : 0) << 1 | (nextIsWS ? 1 : 0);
return b;
}
/**
"If an operator has whitespace on the right side only, it is treated as a
postfix unary operator. As an example, the ++ operator in a++ b is treated
as a postfix unary operator."
"If an operator has no whitespace on the left but is followed immediately
by a dot (.), it is treated as a postfix unary operator. As an example,
the ++ operator in a++.b is treated as a postfix unary operator (a++ .b
rather than a ++ .b)."
*/
public static boolean isPostfixOp(ITokenStream tokens) {
int stop = getLastOpTokenIndex(tokens);
if (stop == -1) return false;
int start = tokens.Index;
var prevToken = tokens.get(start - 1); // includes hidden-channel tokens
var nextToken = tokens.get(stop + 1);
var prevIsWS = isLeftOperatorWS(prevToken);
var nextIsWS = isRightOperatorWS(nextToken);
var result =
!prevIsWS && nextIsWS ||
!prevIsWS && nextToken.getType() == SwiftParser.DOT;
var text = tokens.GetText(Interval.Of(start, stop));
//System.out.println("isPostfixOp: '"+prevToken+"','"+text+"','"+nextToken+"' is "+result);
return result;
}
/** Find stop token index of next operator; return -1 if not operator. */
public static int getLastOpTokenIndex(ITokenStream tokens) {
var i = tokens.Index; // current on-channel lookahead token index
var lt = tokens.Get(i);
if (lt.getType() == SwiftParser.DOT && tokens.get(i + 1).getType() == SwiftParser.DOT) {
// dot-operator
i += 2; // point at token after ".."
lt = tokens.get(i);
while (lt.getType() != Token.EOF &&
(lt.getType() == SwiftParser.DOT || isOperatorChar(lt.getType()))) {
i++;
lt = tokens.get(i);
}
return i - 1;
}
// Is it regular operator?
if (!isOperatorHead(lt.getType())) {
return -1;
}
i++;
lt = tokens.get(i);
while (lt.getType() != Token.EOF && isOperatorChar(lt.getType())) {
i++;
lt = tokens.get(i);
}
int stop = i - 1;
return stop;
}
