Re: quoting vs syntax quoting

2020-03-02 Thread Alan Thompson 
It is even simpler if you just run the following code:

(println "plain-quote:   " 'map)
(println "syntax-quote:  " `map)


with result:

plain-quote:map
syntax-quote:   clojure.core/map


The syntax-quote also allows you to unquote forms using `~` and `~@` (you
can't do this with plain-quote).  The combination allows you to easily make
code templates, the same way you might make HTML templates with Selmer,
Django, etc.

For full details of macro writing, please see this answer:
https://stackoverflow.com/questions/60212576/how-do-i-write-a-clojure-threading-macro

Alan

P.S.  Note that you can use syntax quote in regular functions as a trick to
easily fully-qualify symbol names.  It is not *only* for macros.



On Mon, Mar 2, 2020 at 4:49 AM Rutvik Patel  wrote:

> > How can I make a symbol without a namespace in syntax quoting?
> You need quote + unquote.
>
> user=> (defmacro moo2 [] `(defn ~'foo []))
> #'user/moo2
> user=> (macroexpand-1 '(moo2))
> (clojure.core/defn foo [])
> user=> (moo2)
> #'user/foo
>
> Focus on *~'foo *thing, we first *quote* the foo and *unquote* is using ~.
>
> On Mon, Mar 2, 2020 at 4:09 PM Anatoly Smolyaninov 
> wrote:
>
>> Yes, backtick is hygienic, i.e. it adds ns to symbols. you can define
>> name first and inject:
>>
>> ```
>> (defmacro moo2 []
>>   (let [name (symbol "foo")]
>> `(defn ~name [])))
>>
>> ```
>>
>> понедельник, 2 марта 2020 г., 10:54:51 UTC+1 пользователь Sonny To
>> написал:
>>>
>>> (defmacro moo1 []
>>>   '(defn foo []))
>>>
>>> (defmacro moo2 []
>>>
>>>
>>>   `(defn foo []))
>>>
>>> stigmergy.wocket.server> (moo1)
>>>
>>> #'stigmergy.wocket.server/foo
>>>
>>>
>>> stigmergy.wocket.server> (moo2)
>>>
>>> CompilerException clojure.lang.ExceptionInfo: Call to clojure.core/defn
>>> did not conform to spec:
>>> In: [0] val: stigmergy.wocket.server/foo fails spec:
>>> :clojure.core.specs.alpha/defn-args at: [:args :name] predicat\
>>> e: simple-symbol?
>>>
>>>  #:clojure.spec.alpha{:problems [{:path [:args :name], :pred
>>> clojure.core/simple-symbol?, :val stigmergy.wocket.ser\
>>> ver/foo, :via [:clojure.core.specs.alpha/defn-args
>>> :clojure.core.specs.alpha/defn-args], :in [0]}], :spec #object[c\
>>> lojure.spec.alpha$regex_spec_impl$reify__2436 0x33d84248
>>> "clojure.spec.alpha$regex_spec_impl$reify__2436@33d84248"]\
>>> , :value (stigmergy.wocket.server/foo []), :args
>>> (stigmergy.wocket.server/foo [])}, compiling:(*cider-repl workspac\
>>> e/clj-collage:localhost:39319(clj)*:131:26)
>>>
>>> stigmergy.wocket.server> (macroexpand-1 '(moo1))
>>> (defn foo [])
>>>
>>> stigmergy.wocket.server> (macroexpand-1 '(moo2))
>>> (clojure.core/defn stigmergy.wocket.server/foo [])
>>>
>>>
>>>
>>>
>>> moo1 uses normal quoting while moo2 uses syntax quoting. Why does (moo1)
>>> succeeds but( moo2) fails? Both seem to evaluate to same data-structure
>>> except moo2 has namespaces.
>>>
>>> The error message is cryptic but it seems moo2 is failing on 
>>> clojure.core/simple-symbol?
>>> which seems like a symbol without a namespace.  How can I make a symbol
>>> without a namespace in syntax quoting?
>>>
>>>
>>>
>>>
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Re: quoting vs syntax quoting

2020-03-02 Thread Rutvik Patel 
> How can I make a symbol without a namespace in syntax quoting?
You need quote + unquote.

user=> (defmacro moo2 [] `(defn ~'foo []))
#'user/moo2
user=> (macroexpand-1 '(moo2))
(clojure.core/defn foo [])
user=> (moo2)
#'user/foo

Focus on *~'foo *thing, we first *quote* the foo and *unquote* is using ~.

On Mon, Mar 2, 2020 at 4:09 PM Anatoly Smolyaninov 
wrote:

> Yes, backtick is hygienic, i.e. it adds ns to symbols. you can define name
> first and inject:
>
> ```
> (defmacro moo2 []
>   (let [name (symbol "foo")]
> `(defn ~name [])))
>
> ```
>
> понедельник, 2 марта 2020 г., 10:54:51 UTC+1 пользователь Sonny To написал:
>>
>> (defmacro moo1 []
>>   '(defn foo []))
>>
>> (defmacro moo2 []
>>
>>
>>   `(defn foo []))
>>
>> stigmergy.wocket.server> (moo1)
>>
>> #'stigmergy.wocket.server/foo
>>
>>
>> stigmergy.wocket.server> (moo2)
>>
>> CompilerException clojure.lang.ExceptionInfo: Call to clojure.core/defn
>> did not conform to spec:
>> In: [0] val: stigmergy.wocket.server/foo fails spec:
>> :clojure.core.specs.alpha/defn-args at: [:args :name] predicat\
>> e: simple-symbol?
>>
>>  #:clojure.spec.alpha{:problems [{:path [:args :name], :pred
>> clojure.core/simple-symbol?, :val stigmergy.wocket.ser\
>> ver/foo, :via [:clojure.core.specs.alpha/defn-args
>> :clojure.core.specs.alpha/defn-args], :in [0]}], :spec #object[c\
>> lojure.spec.alpha$regex_spec_impl$reify__2436 0x33d84248
>> "clojure.spec.alpha$regex_spec_impl$reify__2436@33d84248"]\
>> , :value (stigmergy.wocket.server/foo []), :args
>> (stigmergy.wocket.server/foo [])}, compiling:(*cider-repl workspac\
>> e/clj-collage:localhost:39319(clj)*:131:26)
>>
>> stigmergy.wocket.server> (macroexpand-1 '(moo1))
>> (defn foo [])
>>
>> stigmergy.wocket.server> (macroexpand-1 '(moo2))
>> (clojure.core/defn stigmergy.wocket.server/foo [])
>>
>>
>>
>>
>> moo1 uses normal quoting while moo2 uses syntax quoting. Why does (moo1)
>> succeeds but( moo2) fails? Both seem to evaluate to same data-structure
>> except moo2 has namespaces.
>>
>> The error message is cryptic but it seems moo2 is failing on 
>> clojure.core/simple-symbol?
>> which seems like a symbol without a namespace.  How can I make a symbol
>> without a namespace in syntax quoting?
>>
>>
>>
>>
>> --
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> 
> .
>

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Re: quoting vs syntax quoting

2020-03-02 Thread Anatoly Smolyaninov 
Yes, backtick is hygienic, i.e. it adds ns to symbols. you can define name 
first and inject: 

```
(defmacro moo2 []
  (let [name (symbol "foo")]
`(defn ~name [])))

```

понедельник, 2 марта 2020 г., 10:54:51 UTC+1 пользователь Sonny To написал:
>
> (defmacro moo1 []
>   '(defn foo []))
>
> (defmacro moo2 []  
> 
>  
>   `(defn foo []))
>
> stigmergy.wocket.server> (moo1)
>  
> #'stigmergy.wocket.server/foo
>   
>  
> stigmergy.wocket.server> (moo2)
>  
> CompilerException clojure.lang.ExceptionInfo: Call to clojure.core/defn 
> did not conform to spec:
> In: [0] val: stigmergy.wocket.server/foo fails spec: 
> :clojure.core.specs.alpha/defn-args at: [:args :name] predicat\
> e: simple-symbol?  
>  
>  #:clojure.spec.alpha{:problems [{:path [:args :name], :pred 
> clojure.core/simple-symbol?, :val stigmergy.wocket.ser\
> ver/foo, :via [:clojure.core.specs.alpha/defn-args 
> :clojure.core.specs.alpha/defn-args], :in [0]}], :spec #object[c\
> lojure.spec.alpha$regex_spec_impl$reify__2436 0x33d84248 
> "clojure.spec.alpha$regex_spec_impl$reify__2436@33d84248"]\
> , :value (stigmergy.wocket.server/foo []), :args 
> (stigmergy.wocket.server/foo [])}, compiling:(*cider-repl workspac\
> e/clj-collage:localhost:39319(clj)*:131:26)
>
> stigmergy.wocket.server> (macroexpand-1 '(moo1))  
> (defn foo [])   
>
> stigmergy.wocket.server> (macroexpand-1 '(moo2))  
> (clojure.core/defn stigmergy.wocket.server/foo [])   
>
>
>
>
> moo1 uses normal quoting while moo2 uses syntax quoting. Why does (moo1) 
> succeeds but( moo2) fails? Both seem to evaluate to same data-structure 
> except moo2 has namespaces.
>
> The error message is cryptic but it seems moo2 is failing on 
> clojure.core/simple-symbol? 
> which seems like a symbol without a namespace.  How can I make a symbol 
> without a namespace in syntax quoting?
>
>
>
>
>

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quoting vs syntax quoting

2020-03-02 Thread Sonny To 
(defmacro moo1 []
  '(defn foo []))

(defmacro moo2 []  

 
  `(defn foo []))

stigmergy.wocket.server> (moo1)
 
#'stigmergy.wocket.server/foo

   
stigmergy.wocket.server> (moo2)
 
CompilerException clojure.lang.ExceptionInfo: Call to clojure.core/defn did 
not conform to spec:
In: [0] val: stigmergy.wocket.server/foo fails spec: 
:clojure.core.specs.alpha/defn-args at: [:args :name] predicat\
e: simple-symbol?  
 
 #:clojure.spec.alpha{:problems [{:path [:args :name], :pred 
clojure.core/simple-symbol?, :val stigmergy.wocket.ser\
ver/foo, :via [:clojure.core.specs.alpha/defn-args 
:clojure.core.specs.alpha/defn-args], :in [0]}], :spec #object[c\
lojure.spec.alpha$regex_spec_impl$reify__2436 0x33d84248 
"clojure.spec.alpha$regex_spec_impl$reify__2436@33d84248"]\
, :value (stigmergy.wocket.server/foo []), :args 
(stigmergy.wocket.server/foo [])}, compiling:(*cider-repl workspac\
e/clj-collage:localhost:39319(clj)*:131:26)

stigmergy.wocket.server> (macroexpand-1 '(moo1))  
(defn foo [])   

stigmergy.wocket.server> (macroexpand-1 '(moo2))  
(clojure.core/defn stigmergy.wocket.server/foo [])   




moo1 uses normal quoting while moo2 uses syntax quoting. Why does (moo1) 
succeeds but( moo2) fails? Both seem to evaluate to same data-structure 
except moo2 has namespaces.

The error message is cryptic but it seems moo2 is failing on 
clojure.core/simple-symbol? 
which seems like a symbol without a namespace.  How can I make a symbol 
without a namespace in syntax quoting?




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