Why does COBOL have both `SECTION` and `PARAGRAPH`?

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一向 2021-02-18 16:23

Why does COBOL have both SECTION and PARAGRAPH?

Can anybody explain why the designers of COBOL created both SECTIONs and PAR

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  •  春和景丽
    2021-02-18 16:47

    I know this is an old question, but the OP requested about documentation on the original justification of the use of SECTION as well as PARAGRAPH in COBOL.

    You can't get much more "original" than the CODASYL Journal documentation.

    in section 8 of the Journal's specification for the language,

    "COBOL segmentation is a facility that provides a means by which the user may communicate with the compiler to specify object program overlay requirements"

    ( page 331, section 8.1 "Segmentation - General Description")

    "Although it is not mandatory, the Procedure Division for a source program is usually written as a consecutive group of sections, each of which is composed of a series of closely related operations that are designed to collectively perform a particular function. However s when segmentation is used, the entire Procedure Division must be in sections. In addition, each section must be classified as belonging either to the fixed portion or to one of the independent segments of the object program. Segmentation in no way affects the need for qualification of procedure-names to insure uniqueness."

    (p 331, section 8.1.2.1 "Program Segments")

    In her book on comparative programming languages ("Programming Languages: History and Fundamentals", 1969) Jean Sammet (who sat on the CODASYL committee, representing Sylvania Electric) states:

    ".. The storage allocation is handled automatically by the compiler. The prime unit for allocating executable code is a group of sections called a segment. The programmer combines sections be specifying a priority number with each section's name. ... The compiler is required to see that the proper control transfers are provided so that control among segments which are not stored simultaneously can take place. ..."

    (p 369 - 371 V.3 COBOL)

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