Method map

src/main/java/wyil/check/FlowTypeUtils.java:1009–1031

(Function<Row,Row> fn)

		}

		public Typing map(Function<Row,Row> fn) {
			Row[] nRows = matrix;
			// Sanity check existing rows
			for (int i = 0; i != nRows.length; ++i) {
				Row ith = nRows[i];
				Row nith = fn.apply(ith);
				// Sanity check current type
				if(ith != nith && matrix == nRows) {
					nRows = Arrays.copyOf(nRows,nRows.length);
				}
				nRows[i] = nith;
			}
			if(matrix == nRows) {
				return Typing.this;
			} else {
				// Remove any invalid rows
				nRows = ArrayUtils.removeAll(nRows, null);
				// Recalculate number of variables
				int nVariables = nRows.length > 0 ? nRows[0].size() : 0;
				// Create new typing
				return new Typing(subtyping, frames, nVariables, nRows);
			}
		}

		public Typing fold(Comparator<Row> comparator)  {
			if (matrix.length <= 1) {