On 31/12/2017 22:09, Ben Bacarisse wrote:
No, you missed the point and did not address the question. You said (now
cut)
| If I thought introducing functions, whether local or not, as a way of
| avoiding goto was worth doing, I would do so.
but I'm not sure you know if it's worth it or not. So here's my
question again: what language (or languages) were you using when you
concluded that it was not worth using local functions to avoid gotos?
Maybe you had a bad experience from some language that did it badly.
What makes you think I had a bad experience? I posted a version using
Python a few hours ago (which needs the local function to be moved to
work properly).
The same example works in my language (one of them anyway), but I still
find a quick goto the simplest thing to do especially when the code is
not complete so I don't know what will be added or changed or moved,
which will be harder as soon a specific sequence is extracted into a
function.
Also, what would be the duplicated code is seen to 'belong' to one of
the options, rather than be anonymous.
(Here is the same example in my static language:
https://pastebin.com/raw/dX2FNK7a
fn1 uses goto. fn2 uses a local function (not very demanding here so it
works). fn3 uses the special 'block-call' feature which I no longer use
(but I haven't yet got rid of it).
I prefer fn1 and fn3 because the code stays inline. If I had some
inspiration for a better feature then I'd have fn4 and maybe fn5 too.)
Within Python, I touched on performance issues in my earlier post. (A
local function apparently involves an extra assignment - per function -
each time the containing function is called.)
(Which is likely to cause problems if the code includes breaks, or
gotos if the language has them.)
Good grief! That is exactly the sort of code you should not re-use by
jumping to it. There are myriad potential problems and putting the code
into a function will allow the compiler to diagnose lots of them.
OK, forget the gotos then. But a block can still contain break or return
(and in my syntax, several other loop controls). It loses context as
soon as it's hoisted into a function.
--
bartc
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