delimTypeToFont = function(type) {
                    if (type.type === "small") {
                        return "Main-Regular";
                    } else if (type.type === "large") {
                        return "Size" + type.size + "-Regular";
                    } else if (type.type === "stack") {
                        return "Size4-Regular";
                    }
                }
Functions for handling the different types of groups found in the parse
tree. Each function should take a parse group and return a MathML node.