Difference between revisions of "Case.on"
From OpenEUO
m (→Example Usage) |
m (→Example Usage) |
||
| Line 24: | Line 24: | ||
--> c | --> c | ||
| − | + | 5 | |
== Description == | == Description == | ||
Latest revision as of 09:38, 24 November 2010
Calling Pattern
Call
local c = sl.case(casetable) -- later local r[,...] = c.on(sel, arg[, ...])
Args
sel is any type, used as key to lookup in casetable arg0..argN are variadic arguments of any type
Results
r0...rN are the indefinite results of applying arg0...argN to the value found in casetable
Example Usage
local t =
{
[1] = function(...) local a={...} print('a') print(a[a[5] ]) end,
['1'] = function(...) local a={...} print('b') print(a[a[4] ]) end,
bye = function(...) local a={...} print('c') print(a[a[3] ]) end,
default = function(...) local a={...} print('d') print(a[a[2] ]) end,
}
local c = sl.case(t)
local z = 'bye'
c.on(z,2,3,4,5,6)
--> c
5
Description
The method on searches for sel among the keys of casetable. If found and the associated value is a function, then the remaining variadic arguments arg0...argN (if any) are passed to that function and its results are returned as the results to the on invocation. If sel is found but the associated value is not a function, then the actual value is returned as the result of the on invocation. If sel isn't found, then a magic value, 'default' is searched for and if found then its associated value is treated in an identical manner.
Upon Error
If neither the passed sel key or the magic 'default' key are found among the keys of casetable, then an error is reported and handled according to the operant error redirection mode.
