By James F. Gimpel
Communications of the ACM,
June 1972,
Vol. 15 No. 6, Pages 438-447
10.1145/361405.361410
Comments
A new datatype, called a block, has been implemented for SNOBOL4. A block is a three-dimensional aggregate of characters in the form of a right parallelepiped, best thought of as a three-dimensional extension to a string. (The third dimension is used for overstriking.) Blocks may be printed, concatenated in any of three dimensions, and merged on the basis of program-defined connection points. Some blocks adapt in size and shape to their environment.
Blocks and their operations are mainly used for composing printable output. A variety of graphical problems (including flowcharting, bargraphs, logic diagrams, mathematical-equation formation, and text justification and preparation) have been programmed on a printer in what appears to be an easy and natural way. In addition to these somewhat specialized applications, blocks appear to be a good general purpose device-independent output formation mechanism especially suitable for nonnumerical work.
The concept of a block is largely language independent. That is, blocks require little in the way of specialized syntax and could readily be absorbed into the external structure of most programming languages.
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