Brian Dunning's FileMaker Custom Functions

Apply ( function ; value ) OBSOLETE USE ApplyFunction instead

Define an apply a temporary, anonymous function to a value

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Debi Fuchs   Debi Fuchs
Aptworks Consulting
http://www.aptworks.com

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  Sample input:
Let(
sq_plus = "[t]*[t]+[t]";
Apply(sq_plus; 3) +
Apply(sq_plus; 4) +
Apply(sq_plus; 5)
)
  Sample output:
62

  Function definition: (Copy & paste into FileMaker's Edit Custom Function window)

IMPORTANT: Use ApplyFunction instead. It avoids unnecessary complexity used here.

CUSTOM FUNCTION: Apply ( function ; value )
© 2008 Debi Fuchs of Aptworks Consulting, debi@aptworks.com

Apply an "inline" function to a value, handling the value either as a number/expression or as text.

BASIC EXAMPLE:

Let(
square = "[n]*[n]";
Apply( square; 3 ) + Apply( square; 4 ) + Apply( square; "2+3" )
) // --> 50

MULTIPLE ARGUMENT EXAMPLE:

Let(
exp = "GetValue([t];1) ^ GetValue([t];2)";
Apply( exp; List(2;5) ) + Apply( exp; List(3;4) )
) // --> 113

RECURSIVE EXAMPLE:

Let(
$factorial_fn= "if([n]=0;1;[n]*Apply($factorial_fn; [n]-1))";
Apply($factorial_fn; 5)
) // --> 120

MUTUALLY RECURSIVE EXAMPLE:

Let(
[
$even_fn = "if([n]=0; 1; Apply($odd_fn; [n]-1))";
$odd_fn = "if([n]=0; 0; Apply($even_fn; [n]-1))"
];
Apply($even_fn; 8)
) // --> 1


CREDITS: Thanks to Agnès Barouh for the idea of the "[n]" style function call syntax.

USAGE: Return the results of evaluating the string "function", assigning to placeholder "[t]" or "[n]" the given "value". Use "[t]" to treat the value as text; Use "[n]" to evaluate it before application. (Note that the use of "[t]" vs. "[n]" does not directly influence the "type" of the result...only the treatment of the input value.) Use "[n]" over "[t]" where possible, as this is faster; Do NOT use BOTH "[n]" and "[t]" placeholders (or BOTH "[t]"and "evaluate([t])" in one function, as this is very, very slow.

EXAMPLES:

Apply("[n] & 4"; 01+2)
// --> evaluate(3 & 4) --> "34"

Apply("[t] & 4"; 01+2)
// --> evaluate("3" & 4) --> "34"

Apply("[n] & 4"; "01+2")
// --> evaluate(01+2 & 4) --> "34"

Apply("[t] & 4"; "01+2")
// --> evaluate("01+2" & 4) --> "01+24"

Apply("[n] + 4"; "01+2")
// --> 7

Apply("[t] + 4"; "01+2")
// --> 16

Apply("GetAsDate([t])+30"; Date(1;1;2000))
// --> GetAsDate("1/1/2000") + 30 --> 1/31/2000

Apply("GetAsDate([n])+30"; "Date(1;1;2000)")
// --> GetAsDate(Date(1;1;2000)) + 30 --> 1/31/2000

Apply("GetAsDate([n])+30"; Date(1;1;2000))
// --> GetAsDate(1/1/2000) + 30 --> ?

Apply("GetAsDate([n])+30"; GetAsNumber(Date(1;1;2000)))
// --> GetAsDate(730120)+30 --> 1/31/2000

Apply("[t] + [n]"; "01+2")
// --> "01+2" + 01+2 --> 15


IMPLEMENTATION: Evaluate the result of substituting the input into an evaluated "Let" statement, treating the input as EITHER text or a number/expression.

NOTE: See "ApplyToRange" to apply a function to a range of numbers and "ApplyToList" to apply a function to each element of a list.

LAST MODIFIED: 11-AUG-2008 by Debi Fuchs of Aptworks Consulting

 

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