Method parseIf

chapter24/src/main/java/com/seaofnodes/simple/Parser.java:542–547

Parses a statement if ( expression ) statement [else statement] @return a Node, never null

()

     * @return a {@link Node}, never {@code null}
     */
    private Node parseIf() {
        // Parse predicate
        require("(");
        var pred = require(parseAsgn(), ")");
        return parseTrinary(pred,"else");
    }

    // Parse a conditional expression, merging results.
    private Node parseTrinary( Node pred, String fside ) {