Fun with blocks and ops.
[1/2] from: fsievert:uos at: 10-Oct-2000 14:09
Here some fun with a self-modifying block :)
>> a: [append a [+ 1] 1]
== [append a [+ 1] 1]
>> do a
== 1
>> do a
== 2
>> do a
== 3
>> do a
== 4
>> do a
== 5
>> do a
== 6 <---- !
>> do a
== 8 <---- !
>> do a
== 9
And even more fun is:
>> a: [append a '+ append a 1 1]
== [append a '+ append a 1 1]
>> do a
== 1
>> do a
== 2
>> do a
== 3
>> do a
== 4
>> do a
== 5
>> do a
== 7 <-----
>> do a
== 8
[ ..... ]
>> do a
== 12
>> do a
** Script Error: Operator is missing an argument.
** Where: 1 + 1 + 1
>> do a
== 13
>> do a
== 15 <-------
>> do a
== 16
>> do a
== 17
[ .... ]
>> do a
== 28
>> do a
** Script Error: Operator is missing an argument.
** Where: 1 + 1 + 1
>> do a
== 29
>> do a
== 31
[2/2] from: jelinem1::nationwide::com at: 10-Oct-2000 11:30
Hey! This IS fun! I can get all kinds of strange results by tweeking the
block logic.
Among the several versions of incorrect results, I have found how to
achieve the expected results (I must bypass using 'append):
>> a: [insert tail a [+ 1] 1]
== [insert tail a [+ 1] 1]
>> print compose a
1
>> print compose a
2
>> print compose a
3
Using two 'inserts yeilds a different animal, however. Note the block
structure that 'reduce displays:
>> a: [insert tail a '+ insert tail a 1 1]
== [insert tail a '+ insert tail a 1 1]
>> print compose a
1 1
>> print compose a
1 2
>> print compose a
1 3
>> reduce compose a
== [[1] [] 4]
- Michael Jelinek
[fsievert--uos--de] on 10/10/2000 07:09:04 AM
From: [fsievert--uos--de] on 10/10/2000 07:09 AM
Please respond to [list--rebol--com]
To: [list--rebol--com]
cc:
Subject: [REBOL] Fun with blocks and ops.
Here some fun with a self-modifying block :)
>> a: [append a [+ 1] 1]
== [append a [+ 1] 1]
>> do a
== 1
>> do a
== 2
>> do a
== 3
>> do a
== 4
>> do a
== 5
>> do a
== 6 <---- !
>> do a
== 8 <---- !
>> do a
== 9
And even more fun is:
>> a: [append a '+ append a 1 1]
== [append a '+ append a 1 1]
>> do a
== 1
>> do a
== 2
>> do a
== 3
>> do a
== 4
>> do a
== 5
>> do a
== 7 <-----
>> do a
== 8
[ ..... ]
>> do a
== 12
>> do a
** Script Error: Operator is missing an argument.
** Where: 1 + 1 + 1
>> do a
== 13
>> do a
== 15 <-------
>> do a
== 16
>> do a
== 17
[ .... ]
>> do a
== 28
>> do a
** Script Error: Operator is missing an argument.
** Where: 1 + 1 + 1
>> do a
== 29
>> do a
== 31