Elisp: how to make this function short - emacs

I am implementing an plugin, which a lot of project types are remembered. For example: angular, meteor, ember, rails ...
And keyed arguments are used. The function creates an hash table with provided keys and values, and assign the hash table to another hash table.
Code below:
(defun jst-remember-project-type (type &rest args)
"Let JST remember another project type."
(let (label value testing-framework spec-dir config-file source-dir
command-ci command-browser spec-to-target target-to-spec
dominating-files browser-url table)
(while (not (= 0 (length args)))
(setq label (pop args))
(setq value (pop args))
(and (equal :testing-framework label) (setq testing-framework value))
(and (equal :spec-dir label) (setq spec-dir value))
(and (equal :source-dir label) (setq source-dir value))
(and (equal :config-file label) (setq config-file value))
(and (equal :command-ci label) (setq command-ci value))
(and (equal :command-browser label) (setq command-browser value))
(and (equal :browser-url label) (setq browser-url value))
(and (equal :spec-to-target label) (setq spec-to-target value))
(and (equal :target-to-spec label) (setq target-to-spec value))
(and (equal :dominating-files label) (setq dominating-files value)))
(if (gethash type jst-known-project-types)
(error "Redefined JST project type.")
(setq table (make-hash-table :test 'equal))
(puthash :testing-framework testing-framework table)
(puthash :spec-dir spec-dir table)
(puthash :config-file config-file table)
(puthash :source-dir spec-dir table)
(puthash :command-ci command-ci table)
(puthash :command-browser command-browser table)
(puthash :spec-to-target spec-to-target table)
(puthash :target-to-spec target-to-spec table)
(puthash :dominating-files dominating-files table)
(puthash :browser-url browser-url table)
(puthash type table jst-known-project-types))) nil)
And I have a lot of redundant functions like this. I want these kind of functions automatically generated by a macro.
Actually, only a list of keys and a table is needed. Everything else can be generated. However I don't know how to write the macro.
(defmacro jst-remember-keyed (keys table)
"This macro helps with jst-remember functions."
(let (label value QUESTION HERE keys)))
How to convert variable from :symbol and convert :symbol from variable easily?
(make-symbol "fuck")
fuck ;; Error occurs
(let (((make-symbol "fuck") "Diao"))
(message fuck)
) ;; Error occurs
Thanks a lot!

Untested:
(require 'cl)
(defun jst-remember-project-type (type &rest args)
"Let JST remember another project type."
(if (gethash type jst-known-project-types)
(error "Redefined JST project type.""")
(let ((table (make-hash-table :test #'equal)))
(loop for (label value) on args by #'cddr
do (puthash label value table))
(puthash type table jst-known-project-types))))

Related

How to pass bound symbols to functions in elisp?

I am trying to do the following: separate a function that gets values from some user input from the function that uses it.
I have tried the following code for the proof of concept initially (that worked):
(defun initialiser (bindings)
(cl-loop for (var) in bindings do
(set var (read-from-minibuffer "Input value: "))))
That i have tested with:
(let ((name))
(initialiser '((name)))
(message "name is %S" name))
The idea was to pass bindings to the function that handles input in the form like ((name "Name") (address "Post address") (code "County code")) or something similar, and in there assign the input.
After testing above i have come up with the following macro to do things:
(defmacro initialise-and-execute (bindings initialiser &rest callback-actions)
(let ((unwrapped-bindings (map 'list (lambda (binding) (car binding)) bindings)))
`(let ,unwrapped-bindings
(,initialiser (quote ,bindings)
(lambda () ,#callback-actions)))))
However, in the "real" scenario the assignments must happen in callbacks, like:
(defun initialiser(bindings)
(cl-loop for (var) in bindings collect
(lambda () (set var (read-from-minibuffer "Input value: ")))
into callbacks
return callbacks))
This fails to work. Code i have used to test was:
(defvar callbacks nil)
(let ((name))
(setq callbacks (initialiser '((name)))))
(funcall (car callbacks))
Edit: changed the code the following way:
(defmacro initialise-and-execute (bindings initialiser &rest callback-actions)
(let ((unwrapped-bindings (map 'list (lambda (binding) (car binding)) bindings)))
`(lexical-let ,unwrapped-bindings
(,initialiser
(quote ,(map 'list
(lambda (binding) (list (cadr binding)
`(lambda (val) (setq ,(car binding) val))))
bindings))
(lambda () ,#callback-actions)))))
What it must do: generate number of lambdas that share the same lexical environment - one that uses captured variables and the rest that modify them.
However, what i get is, regrettably, something else. Symbols used in callback-actions do not resolve into the values set.
For completeness, here is how i tested it:
(defun init-values (bindings callback)
(loop for (desc setter) in bindings
for idx = 0 then (incf idx)
do (print (format "Setting %s" desc))
(funcall setter idx))
(funcall callback))
(initialise-and-execute
((name "Name")
(surname "Surname"))
init-values
(message "name is %S" name))
Here, lambdas were not generated in a loop and values in the context of a lexical binding were assigned with setq.
To set the function value, use fset, not set.
(defun initialiser(bindings)
(cl-loop for (var) in bindings collect
(lambda () (fset var (read-from-minibuffer "Input value: ")))
into callbacks
return callbacks))
There are possible issues:
in a LOOP the VAR is possibly assigned on each iteration, not bound (that's in Common Lisp). so your callbacks set all the same VAR value.
in a lexical bound Lisp (new in GNU Emacs Lisp) one can't set the variable values with SET
Examples:
ELISP> (mapcar #'funcall
(cl-loop for i in '(1 2 3 4)
collect (lambda () i)))
(4 4 4 4)
all closures have the same value of i
ELISP> (let ((a 'foobar))
(set 'a 42)
a)
foobar
SET had no effect on the local variable
In Common Lisp I might write something like:
(defun initializer (bindings)
(loop for (what setter) in bindings
for new-value = (progn
(format t "Enter ~a: " what)
(finish-output)
(read-line))
do (funcall setter new-value)))
(defmacro call-with-bindings (name-sym-list fn)
(let ((value-sym (gensym "v")))
`(,fn
(list ,#(loop for (name sym) in name-sym-list
collect `(list ,name ,`(lambda (,value-sym)
(setf ,sym ,value-sym))))))))
CL-USER > (let (name age)
(call-with-bindings (("name" name) ("age" age))
initializer)
(format t "name is ~S~%" name)
(values name age))
Enter name: Lara
Enter age: 42
name is "Lara"
"Lara"
"42"
Where we can look at the macro expansion:
CL-USER > (pprint (macroexpand-1
'(call-with-bindings (("name" name) ("age" age))
initializer)))
(INITIALIZER (LIST (LIST "name"
(LAMBDA (#:|v1669|)
(SETF NAME #:|v1669|)))
(LIST "age"
(LAMBDA (#:|v1669|)
(SETF AGE #:|v1669|)))))
After some experimenting, i have been able to do it. The key was realising that lexical-let apparently had some restrictions on how the lambda should be placed for them to have the same closure context. After i have managed to generate set of closures that referred to the same variables, the rest was easy.
Here is the final code:
(defmacro make-lamba-set (bindings &rest callback-actions)
"Make set of closures with shared context
BINDINGS are a list of form (SYMBOL NAME), where SYMBOL is not defined yet
CALLBACK-ACTIONS are forms that use symbols from bindings
Return created captures a as a list of forms:
(do-callback-actions (set-symbol NAME) ...)"
(let ((unwrapped-bindings (map 'list
(lambda (binding)
(car binding))
bindings)))
`(lexical-let ,unwrapped-bindings
(list (lambda () ,#callback-actions)
,#(map 'list
(lambda (binding)
`(list
(lambda (val)
(setq ,(car binding) val))
,(cadr binding)))
bindings)))))
(defmacro initialise-and-execute (bindings initialiser &rest callback-actions)
"BINGINGS have form of ((BINDING-SYMBOL PROMPT) ...)
INITIALISER somehow assigns values to all of BINDING-SYMBOL
then it calls CALLBACK-ACTIONS with values of BINDING-SYMBOL set"
`(let ((closure-parts (make-lamba-set ,bindings ,#callback-actions)))
(,initialiser (cdr closure-parts)
(car closure-parts))))
Here is how i tested it:
(defun init-values (bindings callback)
(loop for (setter desc) in bindings
for idx = 0 then (incf idx)
do (message "Setting %s" desc)
(funcall setter idx))
(funcall callback))
(initialise-and-execute ((name "Name")
(surname "Surname"))
init-values
(insert (format "Name is %S and surname is %S"
name
surname)))
That gave me expected output of:
Name is 0 and surname is 1

How emacs js2-mode jump to definition open in other window?

In js2-mode, M-. runs the command js2-jump-to-definition, this works great. But I want it go to the definition in other window. I find the code js2-jump-to-definition in Github.
What is the easiest way to make it open in other window?
(defun js2-jump-to-definition (&optional arg)
"Jump to the definition of an object's property, variable or function."
(interactive "P")
(if (eval-when-compile (fboundp 'xref-push-marker-stack))
(xref-push-marker-stack)
(ring-insert find-tag-marker-ring (point-marker)))
(js2-reparse)
(let* ((node (js2-node-at-point))
(parent (js2-node-parent node))
(names (if (js2-prop-get-node-p parent)
(reverse (let ((temp (js2-compute-nested-prop-get parent)))
(cl-loop for n in temp
with result = '()
do (push n result)
until (equal node n)
finally return result)))))
node-init)
(unless (and (js2-name-node-p node)
(not (js2-var-init-node-p parent))
(not (js2-function-node-p parent)))
(error "Node is not a supported jump node"))
(push (or (and names (pop names))
(unless (and (js2-object-prop-node-p parent)
(eq node (js2-object-prop-node-left parent)))
node)) names)
(setq node-init (js2-search-scope node names))
;; todo: display list of results in buffer
;; todo: group found references by buffer
(unless node-init
(switch-to-buffer
(catch 'found
(unless arg
(mapc (lambda (b)
(with-current-buffer b
(when (derived-mode-p 'js2-mode)
(setq node-init (js2-search-scope js2-mode-ast names))
(if node-init
(throw 'found b)))))
(buffer-list)))
nil)))
(setq node-init (if (listp node-init) (car node-init) node-init))
(unless node-init
(pop-tag-mark)
(error "No jump location found"))
(goto-char (js2-node-abs-pos node-init))))

How can I cycle through only those buffers which are in a given major mode (such as Python-mode ) ?

How can I cycle through only those buffers which are in a given major mode (such as Python-mode ) ?
Currently I am using C-X-Left/Right arrows, but these also show all sorts of irrelevant (i.e. non source code) buffers, any idea how can I restrict the buffer switching only to a specific type of buffer (with a given major mode) ?
I could not find something ready-made. However, it is not very hard to make the suitable commands.
(defun buffer-mode-alist ()
"Returns a list of (<buffer-name> . <major-mode>) pairs."
(let ((all-buffers (buffer-list))
(rv nil))
(while all-buffers
(let* ((this (car all-buffers))
(name (buffer-name this)))
(setq all-buffers (cdr all-buffers))
(when name
(setq rv (cons (cons name (with-current-buffer this major-mode)) rv)))))
rv))
(defun buffers-with-major-mode (the-major-mode)
(let ((buffer-alist (buffer-mode-alist))
(rv nil))
(while buffer-alist
(let ((this (car buffer-alist)))
(setq buffer-alist (cdr buffer-alist))
(if (eql (cdr this) the-major-mode)
(setq rv (cons (car this) rv)))))
(sort rv #'string<)))
(defun spin-buffers (buffer-list current)
(cond ((not (member current buffer-list)) buffer-list)
((string= current (car buffer-list)) buffer-list)
(t (spin-buffers (append (cdr buffer-list)
(list (car buffer-list)))
current))))
(defvar next-buffer-mode nil)
(defun choose-next-buffer-mode (mode)
"Ask for what major mode should be used as a selector for next-buffer-with-mode."
(interactive "aMajor Mode: ")
(setq next-buffer-mode mode))
(defun next-buffer-with-mode (set)
"Switches to the 'next' buffer with a given mode. If the mode is not set,
require it to be set, by calling choose-next-buffer-mode. If any prefix
argument is passed, also call choose-next-buffer-mode."
(interactive "P")
(when (or (not next-buffer-mode)
set)
(call-interactively 'choose-next-buffer-mode))
(let ((buffers (spin-buffers (buffers-with-major-mode next-buffer-mode)
(buffer-name))))
(when (cdr buffers)
(switch-to-buffer (cadr buffers)))))
(defun prev-buffer-with-mode (set)
"Switches to the 'previous' buffer with a given mode. If the mode is not set,
require it to be set, by calling choose-next-buffer-mode. If any prefix
argument is passed, also call choose-next-buffer-mode."
(interactive "P")
(when (or (not next-buffer-mode)
set)
(call-interactively 'choose-next-buffer-mode))
(let ((buffers (spin-buffers (buffers-with-major-mode next-buffer-mode)
(buffer-name))))
(when buffers
(switch-to-buffer (car (last buffers))))))

Enumerate all tags in org-mode

How do I generate an enumerated list of all tags (e.g., :tag:) in an org-mode file? Say I have a list of the form:
* Head1 :foo:bar:
** Subhead1 :foo:
* Head2
** Subhead2 :foo:bar:
I want to generate a list of all tags in this file as well as how many times each tag was used. Say something like,
:foo: 3
:bar: 2
Here is a shorter version.
(defun get-tag-counts ()
(let ((all-tags '()))
(org-map-entries
(lambda ()
(let ((tag-string (car (last (org-heading-components)))))
(when tag-string
(setq all-tags
(append all-tags (split-string tag-string ":" t)))))))
;; now get counts
(loop for tag in (-uniq all-tags)
collect (cons tag (cl-count tag all-tags :test 'string=)))))
I could not make use of the code posted by John Kitchin, as it requires an interactive function. bpalmer from IRC freenode/#emacs was so kind to help me out. Please find a working example that spits out all tags below the respective tree.
; use this in order to be able to use loop on its own
(require 'cl)
;; count tags (see John's answer)
(defun get-tag-counts ()
(let ((all-tags '()))
(org-map-entries
(lambda ()
(let ((tag-string (car (last (org-heading-components)))))
(when tag-string
(setq all-tags
(append all-tags (split-string tag-string ":" t)))))))
;; now get counts
(loop for tag in (seq-uniq all-tags)
collect (cons tag (cl-count tag all-tags :test 'string=)))))
;; wrap get-tag-counts in an interactive function
(defun create-tag-counts-buffer ()
(interactive)
(let ((tags (get-tag-counts)) (b (get-buffer-create "*Org Tag Count*")))
(dolist (tag tags) (insert (car tag)) (insert "\n")) (display-buffer b)))
Here is an approach.
(setq my-hash (make-hash-table :test 'equal))
(org-map-entries
(lambda ()
(let ((tag-string (car (last (org-heading-components))))
(current-count))
(when tag-string
(dolist (tag (split-string tag-string ":" t))
(setq current-count (gethash tag my-hash))
(if current-count;
(puthash tag (+ 1 current-count) my-hash)
(puthash tag 1 my-hash))
)
)
)
)
)
;; https://github.com/Wilfred/ht.el
(require 'ht)
(ht-map
(lambda (key value)
(list key value))
my-hash)

How do I code walk in elisp?

I'm trying to open a file and read through the sexps. If the form has setq in its first position then traverse the rest of the form adding the in the setq form to an alist.
;;; File passwords.el.gpg
(setq twitter-password "Secret"
github-password "Sauce")
My goal is to able to construct an alist from the pairs in the setq forms in teh file. How I even start?
First, I second the recommendation that you store the passwords in an actual alist and, if necessary, set whatever variables you need to based on that.
That aside, here's another solution that tries to break things out a bit. The -partition function is from the dash.el library, which I highly recommend.
You don't really need to "walk" the code, just read it in and check if its car is setq. The remainder of the form should then be alternating symbols and strings, so you simply partition them by 2 and you have your alist. (Note that the "pairs" will be proper lists as opposed to the dotted pairs in Sean's solution).
(defun setq-form-p (form)
(eq (car form) 'setq))
(defun read-file (filename)
(with-temp-buffer
(insert-file-literally filename)
(read (buffer-substring-no-properties 1 (point-max)))))
(defun credential-pairs (form)
(-partition 2 (cdr form)))
(defun read-credentials-alist (filename)
(let ((form (read-file filename)))
(credential-pairs form)))
;; usage:
(read-credentials-alist "passwords.el")
Alternatively, here's how it would work if you already had the passwords in an alist, like so
(defvar *passwords*
'((twitter-password "Secret")
(github-password "Sauce")))
And then wanted to set the variable twitter-password to "Sauce" and so on. You would just map over it:
(mapcar #'(lambda (pair)
(let ((name (car pair))
(value (cadr pair)))
(set name value)))
*passwords*)
You can use streams to read in the files (read-from-string) and then do the usual elisp hacking. The below isn't robust, but you get the idea. On a file, pwd.el that has your file, it returns the alist ((github-password . "Sauce") (twitter-password . "Secret"))
(defun readit (file)
"Read file. If it has the form (sexp [VAR VALUE]+), return
an alist of the form ((VAR . VALUE) ...)"
(let* (alist
(sexp-len
(with-temp-buffer
(insert-file-contents file)
(read-from-string (buffer-substring 1 (buffer-size)))))
(sexp (car sexp-len)))
(when (equal (car sexp) 'setq)
(setq sexp (cdr sexp))
(while sexp
(let* ((l (car sexp))
(r (cadr sexp)))
(setq alist (cons (cons l r) alist)
sexp (cddr sexp)))))
alist))
(readit "pwd.el")