Re: is it function print has bug？
Thanks for answer my question.
On Saturday, December 26, 2015 at 10:59:51 PM UTC+8, Leif wrote:
>
> Hi, Mian Pao.
>
> When you call the macro te, a is bound to the *symbol* 'print, not the
> *function* print. So, what the ~(a b c) form is doing is calling the
> symbol 'print as a function:
> ('print 1 '(2 3)) => '(2 3)
>
> This is because symbols and keywords implement the function interface, and
> the call above is equivalent to
> (get 1 'print '(2 3)) => '(2 3) ; Tries to look up 'print in the data
> structure 1, fails, uses default value '(2 3).
>
> Hope that helps,
> Leif
>
> On Thursday, December 24, 2015 at 8:38:44 AM UTC-5, Mian Pao wrote:
>>
>> I just write a macro
>>
>> ```
>> (defmacro te
>> [a b & c]
>> `(print
>> ~(a b c)))
>> ```
>>
>> and i run
>>
>> ```
>> (macroexpand '(te print 2 3 4))
>> ;=> (clojure.core/print (3 4))
>> ```
>>
>> it get `(clojure.core/print (3 4))` not `(clojure.core/print nil)`
>>
>> iti is mean `(print 2 '(3 4))` return (3 4)?
>>
>
--
You received this message because you are subscribed to the Google
Groups "Clojure" group.
To post to this group, send email to clojure@googlegroups.com
Note that posts from new members are moderated - please be patient with your
first post.
To unsubscribe from this group, send email to
clojure+unsubscr...@googlegroups.com
For more options, visit this group at
http://groups.google.com/group/clojure?hl=en
---
You received this message because you are subscribed to the Google Groups
"Clojure" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to clojure+unsubscr...@googlegroups.com.
For more options, visit https://groups.google.com/d/optout.
Re: is it function print has bug？
Hi, Mian Pao.
When you call the macro te, a is bound to the *symbol* 'print, not the
*function* print. So, what the ~(a b c) form is doing is calling the
symbol 'print as a function:
('print 1 '(2 3)) => '(2 3)
This is because symbols and keywords implement the function interface, and
the call above is equivalent to
(get 1 'print '(2 3)) => '(2 3) ; Tries to look up 'print in the data
structure 1, fails, uses default value '(2 3).
Hope that helps,
Leif
On Thursday, December 24, 2015 at 8:38:44 AM UTC-5, Mian Pao wrote:
>
> I just write a macro
>
> ```
> (defmacro te
> [a b & c]
> `(print
> ~(a b c)))
> ```
>
> and i run
>
> ```
> (macroexpand '(te print 2 3 4))
> ;=> (clojure.core/print (3 4))
> ```
>
> it get `(clojure.core/print (3 4))` not `(clojure.core/print nil)`
>
> iti is mean `(print 2 '(3 4))` return (3 4)?
>
--
You received this message because you are subscribed to the Google
Groups "Clojure" group.
To post to this group, send email to clojure@googlegroups.com
Note that posts from new members are moderated - please be patient with your
first post.
To unsubscribe from this group, send email to
clojure+unsubscr...@googlegroups.com
For more options, visit this group at
http://groups.google.com/group/clojure?hl=en
---
You received this message because you are subscribed to the Google Groups
"Clojure" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to clojure+unsubscr...@googlegroups.com.
For more options, visit https://groups.google.com/d/optout.
Re: is it function print has bug？
Hi, Mian Pao.
When you call the macro te, a is bound to the *symbol* 'print, not the
*function* print. So, what the ~(a b c) form is doing is calling the
symbol 'print as a function:
('print 1 '(2 3)) => '(2 3)
This is because symbols and keywords implement the function interface, and
the call above is equivalent to
(get 1 'print '(2 3)) => '(2 3) ; Tries to look up 'print in the data
structure 1, fails, uses default value '(2 3).
Hope that helps,
Leif
On Thursday, December 24, 2015 at 8:38:44 AM UTC-5, Mian Pao wrote:
>
> I just write a macro
>
> ```
> (defmacro te
> [a b & c]
> `(print
> ~(a b c)))
> ```
>
> and i run
>
> ```
> (macroexpand '(te print 2 3 4))
> ;=> (clojure.core/print (3 4))
> ```
>
> it get `(clojure.core/print (3 4))` not `(clojure.core/print nil)`
>
> iti is mean `(print 2 '(3 4))` return (3 4)?
>
--
You received this message because you are subscribed to the Google
Groups "Clojure" group.
To post to this group, send email to clojure@googlegroups.com
Note that posts from new members are moderated - please be patient with your
first post.
To unsubscribe from this group, send email to
clojure+unsubscr...@googlegroups.com
For more options, visit this group at
http://groups.google.com/group/clojure?hl=en
---
You received this message because you are subscribed to the Google Groups
"Clojure" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to clojure+unsubscr...@googlegroups.com.
For more options, visit https://groups.google.com/d/optout.
is it function print has bug？
I just write a macro ``` (defmacro te [a b & c] `(print ~(a b c))) ``` and i run ``` (macroexpand '(te print 2 3 4)) ;=> (clojure.core/print (3 4)) ``` it get `(clojure.core/print (3 4))` not `(clojure.core/print nil)` iti is mean `(print 2 '(3 4))` return (3 4)? -- You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups "Clojure" group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
