update:
replace
"obj:=5; for each filter in FILTERS do filter(obj); od;"
with
"obj:=5; for filter in FILTERS do filter(obj); od;"
Am 25.02.2012 00:02, schrieb kroeker:
Hello Frank,
thanks, "AllOperations" comes already very close to my needs.
Maybe you could also give me an advice, how to find
all filters which are applicable to an object:
"IsEmpty" is not applicable to an int and therefore
"obj:=5; for each filter in FILTERS do filter(obj); od;"
fails with an error.
Thank you,
Jakob
Am 23.02.2012 23:07, schrieb Frank Lübeck:
On Thu, Feb 23, 2012 at 08:11:20PM +0000, Alexander Konovalov wrote:
I've noticed that this question was not answered yet in the Forum:
On 9 Jan 2012, at 09:59, kroeker wrote:
Hello,
sometimes I am looking for a function which is applicable to a
specific object
without knowing the name of the function. To find the desired function
I have to read a lot of documentation, look for examples, ask an
experienced GAP programmer (or the GAP-Forum) and so on.
Would it be possible to implement a search through all existing
functions
where one of the parameters is an object of a specified type?
So, the short answer is 'No' - GAP function may take any
argument(s), one does not
specify to which arguments it applies when the function is created.
GAP also
has a notion of 'operation' which is a bunch of functions, called
'methods'
- these are installed with particular requirements on their
arguments. Here
you may call ApplicableMethod (see ?ApplicableMethod) to get the
function
which will be applied to arguments in a call to a specified
operation - but
this is not what you want, since you need to know the name of the
operation
in advance. For example,
Dear Jakob, dear Forum,
Sorry, I must have overlooked the original post.
This reminds me that I have once written a utility function
AllOperations(obj)
which returns a list of 6 lists of names of operations such that
the operations from the i-th list have a method that allows obj as
argument number i.
I think (a variant of) this is used for a completion function in the
Sage interface to GAP. The function is appended below.
As Alexander pointed out, something like that is only possible for
operations (whose methods are installed with requirements on the
arguments)
and not for general functions in GAP.
With best regards,
Frank
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