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FIELDWBLOCK()
Return a set-get code block for a field in a given work area
------------------------------------------------------------------------------
Syntax
FIELDWBLOCK(<cFieldName>, <nWorkArea>)
--> bFieldWBlock
Arguments
<cFieldName> is the name of the field specified as a character
string.
<nWorkArea> is the work area number where the field resides
specified as a numeric value.
Returns
FIELDWBLOCK() returns a code block that, when evaluated, sets (assigns)
or gets (retrieves) the value of <cFieldName> in the work area
designated by <nWorkArea>. If <cFieldName> does not exist in the
specified work area, FIELDWBLOCK() returns an empty block.
Description
FIELDWBLOCK() is a database function that builds a code block. When
evaluated with the EVAL() function, the code block first selects the
designated <nWorkArea>. If an argument was passed, the code block then
assigns the value of the argument to <cFieldName>. If no argument was
passed, the code block retrieves the value of <cFieldName>. The
original work area is then reselected before the code block returns
control.
Note that the specified field variable may not exist when the code block
is created but must exist before the code block is executed.
Notes
. FIELDWBLOCK() is similar to FIELDBLOCK(), except that
FIELDBLOCK() incorporates a fixed work area into the set-get block.
Examples
. This example compares FIELDWBLOCK() to a code block created
using the macro operator. Note that using FIELDWBLOCK() avoids the
speed and size overhead of the macro operator:
// Set-Get block for work area 1 defined with
// macro operator
bSetGet := &( "{ |setVal| IF( setVal == NIL, ;
1->FName, 1->FName := setVal ) }" )
// Set-Get block defined using FIELDWBLOCK()
// bSetGet created here is the functional
// equivalent of bSetGet above
bSetGet := FIELDWBLOCK("FName", 1)
Files Library is CLIPPER.LIB.
See Also:
FIELDBLOCK()
MEMVARBLOCK()
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