IntroductionIdentifier files (IDS) are used in the IE mainly as lookup files. Referenced from script and dialog, IDS files allow a symbolic identifier to be used instead of a literal number. This increases readability and eases the process of creating scripts. The references contained in script files (BCS, BS) are removed at compile-time, and replaced with the actual value. The references contained in dialog files are maintained, and are converted at run-time by the engine. This means that the data within IDS files can affect the game, and it is important that the data is consistent. IDS files are generally optional - the a numeric value can be specified directly in script, without having to specify a string to lookup in an IDS file - this especially applies to spell.ids (the engine will convert a numeric entry into the relevant filename automatically).
Note that some IDS files shipped with the various IE games are incorrect; corrected versions of these files are available in the IESDP, as well as the original files.