On 2022-06-01 17:44, Alex Tweedly via use-livecode wrote:
I was surprised to find that
constant K = TRUE
produces an error, though
constant K = true
is fine. In other contexts, you can say
put TRUE into myVar
put true into hisVar
etc.
but in a constant statement, it seems to be case sensitive.
Anyone got an interesting story (or theory) on why ? :-)
Its a small mitigation of
https://quality.livecode.com/show_bug.cgi?id=19413 - i.e. where the
initializer of constants (and locals) is currently treated as a single
literal.
In explicitVariables mode, unquoted literals are allowed on the RHS only
if the literal is a (builtin) constant *and* the constants value is
identical to the token you have provided.
That extra check is there to ensure that the constants (and
initializers) you have used are actually what you intended.
Currently - the following does not do what you think:
constant kEmptyString = empty
Indeed, this isn't allowed in explicitVariables mode, as the constant
empty's value is "" and not "empty" - which is what kEmptyString will
actually be with explicitVariables turned off.
Anyway, this rather odd and obscure facet of the language will disappear
in 10 as we've made it so that initializers for constants and locals can
be constant expressions. Thus:
constant kTrue = TRUE
local sEmptyString = empty
Will do precisely what they look like they should do...
Also, you'll be able to do things like:
constant kPiBy2 = pi / 2
constant kPiBy2Squared = kPiBy2 * kPiBy2
constant kPiBy2String = format("%f", kPiBy2)
local sPiMap = { "pi-by-2": kPiBy2, "pi-by-2-sq": kPiBy2Squared }
Warmest Regards,
Mark.
P.S. Amusingly, your question came up on exactly the same day I
'finished' my patch for the above - it now awaits review which may
result in it not being quite finished ;)
--
Mark Waddingham ~ m...@livecode.com ~ http://www.livecode.com/
LiveCode: Everyone can create apps
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