REBOL 3 Docs Guide Concepts Functions Datatypes Errors
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REBOL 3 Functions: ??

??  name

Debug print a word, path, or block of such, followed by its molded value.


name - Word, path, and block to obtain values.

See also:

probe   help   ?   mold   source  


The ?? function prints the variable named, followed by its value. It also returns the value. It is a quite useful for debugging.

a: 10
?? a
a: 10

Like probe, ?? can be inserting into code with minimal effect:

a: 10
b: 20
a + ?? b
b: 20

If a block is provided, then each value is printed:

?? [a b]
a: 10  b: 20
Warning: effect on functions

If you use ?? in front of a function, the function value is returned. The function is not evaluated.

>> ?? find "abc" "a"
find: make action! [[
    {Finds a value in a series and returns the series at the start of it.}
    series [series! gob! port! bitset! typeset! object! none!]
    value [any-type!]
    /part "Limits the search to a given length or position"

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