How can I refer to date as argument in f within the foreach loop if date is also used as block element var ? Am I obliged to rename my date var ?
f: func[data [block!] date [date!]][
foreach [date o h l c v] data [
]
]
views:
62answers:
3
+2
A:
You need to either change the parameter name from date or assign it to a local variable.
Graham Chiu
2010-09-07 23:43:00
+2
A:
You can access the date argument inside the foreach loop by binding the 'date word from the function specification to the data argument:
>> f: func[data [block!] date [date!]][
[ foreach [date o h l c v] data [
[ print last reduce bind find first :f 'date 'data
[ print date
[ ]
[ ]
>> f [1-1-10 1 2 3 4 5 2-1-10 1 2 3 4 5] 8-9-10
8-Sep-2010
1-Jan-2010
8-Sep-2010
2-Jan-2010
It makes the code very difficult to read though. I think it would be better to assign the date argument to a local variable inside the function as Graham suggested.
>> f: func [data [block!] date [date!] /local the-date ][
[ the-date: :date
[ foreach [date o h l c v] data [
[ print the-date
[ print date
[ ]
[ ]
>> f [1-1-10 1 2 3 4 5 2-1-10 1 2 3 4 5] 8-9-10
8-Sep-2010
1-Jan-2010
8-Sep-2010
2-Jan-2010
Peter W A Wood
2010-09-08 00:37:29
The technique of binding an additional argument to a block would be more difficult to apply if the foreach loop was iterating over the elements of the block one at a time. There would probably be an additional iteration for the date.
Peter W A Wood
2010-09-08 00:52:24
+4
A:
A: simple, compose is your best friend.
f: func[data [block!] date [date!]][
foreach [date str] data compose [
print (date)
print date
]
]
>> f [2010-09-01 "first of sept" 2010-10-01 "first of october"] now
7-Sep-2010/21:19:05-4:00
1-Sep-2010
7-Sep-2010/21:19:05-4:00
1-Oct-2010
moliad
2010-09-08 01:21:37
obviously, all parens are replaced, so in some situations the above is either impossible or unwieldy, but in the vast majority of cases, it works.
moliad
2010-09-08 01:27:25