6 ms·

Nah, I just do {:color “brown” :name “fred”}

dreamcompiler 7y ago
That works in Clojure but not "Lisp" in general, which is what the parent asked about and for which they gave an example.
- deleted 7y ago
  [deleted]
- svetlyak40wt 7y ago
  You can define your own syntax in CL: CL-USER> (set-macro-character #\{ (lambda (str char) (declare (ignore char)) (let ((*readtable* (copy-readtable *readtable* nil)) (keep-going t)) (set-macro-character #\} (lambda (stream char) (declare (ignore char) (ignore stream)) (setf keep-going nil))) (let ((pairs (loop for key = (read str nil nil t) while keep-going for value = (read str nil nil t) collect (list key value))) (retn (gensym))) `(let ((,retn (make-hash-table :test #'equal))) ,@(mapcar (lambda (pair) `(setf (gethash ,(car pair) ,retn) ,(cadr pair))) pairs) ,retn))))) T CL-USER> {:foo 100500 :bar 42} #<HASH-TABLE :TEST EQUAL :COUNT 2 {1005879463}> CL-USER> (alexandria:hash-table-alist #v1) ((:BAR . 42) (:FOO . 100500)) CL-USER> And define a printer for the hash to output it as desired: CL-USER> (defmethod print-object ((obj hash-table) stream) (princ "{" stream) (loop with indent = nil for key being the hash-keys in obj using (hash-value value) when indent do (format stream "~% ") unless indent do (setf indent t) do (format stream "~S ~S" key value)) (princ "}" stream)) #<STANDARD-METHOD COMMON-LISP:PRINT-OBJECT (HASH-TABLE T) {10040C9F83}> CL-USER> {:foo 100500 :bar 42} {:FOO 100500 :BAR 42}
singularity2001 7y ago
Thanks, that was perfectly interesting. Can you still do it in the above-mentioned way in clojure: ? (defparameter a '((color brown) (name fred)))
- LandR 7y ago
  Clojure data structures are immutable, so getters and setters are mostly out. In CLojure, maps are functions and keywords are also functions. But you could do: (def foo {:color "brown" :name "fred"}) Anytime you want to get the color out you can just call the :color function and pass the map (:color foo) => "brown" (:name foo) => "fred" Likewise, we can call the map as the function and pass the key as the argument (foo :name) => "fred" We also have nice ways to destructure and bind values in maps when passed as parameters to functions (defn my-func [{:keys [color name]}] (println "Color: " color) (println "Name: " name)) (my-func foo) => Color: brown Name: fred

That works in Clojure but not "Lisp" in general, which is what the parent asked about and for which they gave an example.

deleted 7y ago
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svetlyak40wt 7y ago
You can define your own syntax in CL: CL-USER> (set-macro-character #\{ (lambda (str char) (declare (ignore char)) (let ((*readtable* (copy-readtable *readtable* nil)) (keep-going t)) (set-macro-character #\} (lambda (stream char) (declare (ignore char) (ignore stream)) (setf keep-going nil))) (let ((pairs (loop for key = (read str nil nil t) while keep-going for value = (read str nil nil t) collect (list key value))) (retn (gensym))) `(let ((,retn (make-hash-table :test #'equal))) ,@(mapcar (lambda (pair) `(setf (gethash ,(car pair) ,retn) ,(cadr pair))) pairs) ,retn))))) T CL-USER> {:foo 100500 :bar 42} #<HASH-TABLE :TEST EQUAL :COUNT 2 {1005879463}> CL-USER> (alexandria:hash-table-alist #v1) ((:BAR . 42) (:FOO . 100500)) CL-USER> And define a printer for the hash to output it as desired: CL-USER> (defmethod print-object ((obj hash-table) stream) (princ "{" stream) (loop with indent = nil for key being the hash-keys in obj using (hash-value value) when indent do (format stream "~% ") unless indent do (setf indent t) do (format stream "~S ~S" key value)) (princ "}" stream)) #<STANDARD-METHOD COMMON-LISP:PRINT-OBJECT (HASH-TABLE T) {10040C9F83}> CL-USER> {:foo 100500 :bar 42} {:FOO 100500 :BAR 42}

singularity2001 7y ago

Thanks, that was perfectly interesting. Can you still do it in the above-mentioned way in clojure: ? (defparameter a '((color brown) (name fred)))

LandR 7y ago
Clojure data structures are immutable, so getters and setters are mostly out. In CLojure, maps are functions and keywords are also functions. But you could do: (def foo {:color "brown" :name "fred"}) Anytime you want to get the color out you can just call the :color function and pass the map (:color foo) => "brown" (:name foo) => "fred" Likewise, we can call the map as the function and pass the key as the argument (foo :name) => "fred" We also have nice ways to destructure and bind values in maps when passed as parameters to functions (defn my-func [{:keys [color name]}] (println "Color: " color) (println "Name: " name)) (my-func foo) => Color: brown Name: fred