On 5/23/07, Terrence Brannon <[EMAIL PROTECTED]> wrote:
but then I immediately hit a problem.
c=. '(' , [ , ')' ,~ ]
'a' c 'b' c 'c'
(a(bc))
That was all well and good, but I wanted a more "pictorial" way to form the
string, so I tried to move the "]" inside the parenthesis, since that is what c
does... 'b' c 'c' creates (bc) and so I wanted the verb to look the same way
too.
So I tried:
c=. '(' , [ , ] , ')'
but I got a syntax error when I tried to run it.
I think your problem here is more visual than anything else. Your first
definition of c is a verb, built up as a train of nouns and verbs. Your
syntax error definition of c has a noun for the right-most word. That
means that you're either defining a noun or generating a syntax error.
J will automatically promote nouns to (constant) verbs when they appear
as the leftmost tine of a train, but if you want a constant noun as the
rightmost tine of a train, you need to do this manually. In this case:
c=. '(', [ , ] , ')'"_
Or, since [,] is , (and since the lone comma would be in an odd
position in a fork train) more concisely:
c=. '(', , , ')'"_
Another thing you might try, to better understand this, would be
to take your original sentence, and start throwing things out:
'a' c 'b' c 'c'
(a(bc))
'b' c 'c'
(bc)
'b' ('(' , [ , ')' ,~ ]) 'c'
(bc)
'b' ([ , ')' ,~ ]) 'c'
bc)
'b' (')' ,~ ]) 'c'
c)
Now compare:
')' ,~ ]
')' ,~ ]
] , ')'
)
Notice how the first of these last two expressions is a verb, while the
other is a noun? This follows through so that when you define:
c=. '(' , [ , ] , ')'
c is a noun (look at its definition). So when you try using it as a
verb, you get a syntax error.
So why is it that [ , 'c)' will work but my attempt to have
] , ')' work will not?
I hope I've explained this well enough?
Thanks,
--
Raul
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