The ReadNextFloat(file) command attempts to read a float from file.  The ReadNextFloat function skips characters until it finds a valid float.  It then reads the float and returns it.  If no characters match a valid float, then the end of file is reached and NULL is returned.

If file is the name of a file that has not been opened, Maple attempts to open the file before attempting to read the float.

An error is raised if file is not a valid descriptor or if it is the name of a file that cannot be opened.