A-Correlative Conversion (A)

A-Correlative Conversion (A)

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The A conversion code allows expressions formed as A-correlatives to be used as conversions. These are provided to ease migration from other systems and their use is not recommended for new developments.

 

The full format of this conversion code is

 

A; expression

 

where

 

expressionis constructed in exactly the same way as an A-correlative.

 

 

Use of A-correlatives as conversion codes can lead to poor performance as they must be transformed to the equivalent F-correlative and then processed interpretively. When used in the query processor, this transformation is performed during parsing of the query sentence and hence only occurs once. When used with the QMBasic ICONV() or OCONV() functions, the transformation will occur on every use of the conversion function.

 

An A-correlative used as a conversion code with ICONV() or OCONV() must not contain N() functions as these cannot be resolved without the dictionary.

 

When used in field 8 of a Pick style dictionary record, an A-correlative expression is compiled in the same way as an I-type for optimum performance. The compiled version of the expression is stored in the dictionary in fields 15 onwards though the ED and SED editors will hide it.