Abstract: A data processing system for processing planar-oriented computer output data to provide customized output for each user. The system, called phaser, specifies two-dimensional portions of such planar-output for processing to permit page-oriented editing of the planar output. Portions of pages can be identified by column and line numbers, by box and block coordinates, and by matching plane-oriented patterns. Prior to processing, such varied page specifications are converted to segment lists of line segments to permit uniform processing. Phaser statements are compiled and executed in working sets which can be invoked in series or in parallel (on the same data input) to permit union and intersection operations.