Namespaces

[actondev]

This issue is meant for organization/documentation purposes.

As s7 scheme doesn't have any separate module/namespace structure, coming from clojure I really missed this feature. So I cam up with a solution. See https://github.com/actonDev/s7-imgui/blob/b59927d/src/scheme/aod/ns.scm at the time of writing

Example usage:

(ns foo.bar)
;; sets the *ns* symbol in a new environment (let)
;; subsequent calls are evaluated in this environment
;; this is done by the repl from the c side. see
;; https://github.com/actonDev/s7-imgui/blob/b59927d2c875ff713aeddc8476973e8329e6f802/src/aod/s7/repl.cpp#L39

(ns-require foo.bar2)
(ns-require foo.bar3 :as bar3)
;; fully qualified namespace for calling
(foo.bar2/hi)

;; call with alias
(bar3/hi)

;; shows the current namespace
*ns*

;; the following are equivalent
;; --- BEGIN equivalent
(with-ns foo.bar2
	 (hi))

;; *nss* mnemonic: plurar of ns. NameSpaceS
(with-let (*nss* 'foo.bar2)
	  (hi))
;; this changes the *ns*
(ns foo.bar2)
(hi)
;; ---- END equivalent

;; WARNING
;; now foo.bar2/hi and bar3/hi are NOT available
;; to make them available we have to switch back:
(ns foo.bar)

[actondev]

This makes the following scenario possible

• User changes the definition of the hi function in foo.bar2
• The changes are reflected when calling foo.bar2/hi in the foo.bar namespace

This is done like this:

• the ns-require loads the required namespace in its own environment. Specifically it puts it under the, eg for the foo.bar2 case, foo.bar2 key in the *nss* hashtable
• In the require-er side (foo.bar) we create the symbol foo.bar2/hi (and a symbol for every symbol in the foo.bar2 namespace) which is a lambda:
  (https://github.com/actonDev/s7-imgui/blob/b59927d/src/scheme/aod/ns.scm#L131)

(lambda args
  (eval `(apply ,func-symbol ',args) (*nss* the-target-ns)
	))

TODO

• bind the required namespaces symbol value directly to our namespace when in production mode?
  would like to make some benchmarks to see the difference in performance

For that benchmark see https://github.com/actonDev/s7-imgui/blob/0.1.0/test/scheme/test-benchmark.scm
the gist: calling (fib 5) 1000000 times

The dynamic version:
ns-require: Time fib 5 times x 1000000 (#t 1.686106) 

The native scheme require version:
require: Time fib 5 times x 1000000 (#t 0.8520600000000003) 

The ns-require but with :dynamic #f version
ns-require :dynamic #f : Time fib 5 times x 1000000 (#t 0.8458799999999997) 

[actondev]

Emacs bindings for switching namespaces, evaluating sexp under current namespace

;; Some helper funcionts for workin with s7 namely, changing
;; "namespace" with (ns ..) forms ala clojure tyle
;; 
;; Pardon the non-elisp-idiomatic dots and slashes but I really prefer
;; this namespace/clojure sytnax

(require 'cmuscheme)

(defun aod.s7/get-ns ()
  "Get the namespace name to send on the repl.
NOTE: you need to have the (ns) in the beginning of the
line. This is to not mistake things after ;; comments"
  (save-excursion
    (beginning-of-buffer)
    (if (re-search-forward "^\(ns \\([a-zA-Z0-9\.\-]+\\)" nil t)
	(match-string-no-properties 1)
      nil)))

(defun aod.s7/switch-to-ns ()
  "Switches to the namespace of the currently open buffer."
  (interactive)
  (if-let ((ns (aod.s7/get-ns)))
      (progn
	(message (format "switching to ns %s" ns))
	(scheme-send-string (format "(ns %s)" ns)))
    ;; else
    (progn
      (message "switching to (rootlet)")
      (scheme-send-string "(set! *ns* (rootlet))"))))

(defun aod.s7/top-level-sexp ()
  "Gets the top level sexp without any trailing new lines"
  (save-excursion
    (end-of-defun)
    (let ((end (point)))
      (beginning-of-defun)
      (string-trim
       (buffer-substring-no-properties (point) end)))))

(defun aod.s7/send-definition ()
  "Sends the top level sexp under point.
Note: (scheme-send-definition) would send 2 things:
1. The top level sexp with a new line at the end (cause of (end-of-defun))
2. The '\n' string as well. (extra commint command)

Here we just send ounce the trimmed top level sexp"
  (interactive)
  (aod.s7/switch-to-ns)
  (scheme-send-string
   (aod.s7/top-level-sexp)))

(defun aod.s7/send-last-sexp ()
  "Send the last sexp"
  (interactive)
  (aod.s7/switch-to-ns)
  (scheme-send-last-sexp)
  )

(provide 'aod-s7)

Then, to use it:

(use-package aod-s7
  :load-path "elisp/" ;;wherever the above .el files resides
  ;; the after apparently is needed..
  ;; if not, the bindings are not there even if in a scheme file
  ;; and having started a scheme with (run-scheme)
  :after (cmuscheme)
  :bind(
	:map scheme-mode-map
	("C-<return>" . aod.s7/send-definition)
	("M-<return>" . aod.s7/send-last-sexp)
	)
  )

That binds the

• ctrl-enter (sending top level definitions)
• alt-enter (sending the last sexp : useful for things inside a comment block etc

[actondev]

Updates:

• Allowing :require in the ns call.
• special usecase: if the passed namespace name is rootlet, that will require things directly into (rootlet)

Example:

(ns rootlet
    :require ((aod.c.foreign :as c)
	      (aod.c.imgui :as ig)
	      (aod.imgui.macros :as igm)
	      (aod.c.nfd)
	      (aod.c.imgui.window-flags :as igw)))

[actondev]

Update:

• added :doc parameter to the ns macro

example usage

(ns aod.imgui.macros
    :doc "Some macros to make life easier while working with ImGui.
The usual syntax is (args . body)
- args are applied to corresponding raw imgui function
- body is executed either in a when block (eg when a menu items is active)
  or wrapped between the begin/end calls"
    :require
    ((aod.c.imgui :as ig)))

This is used to generate the documentation. see https://github.com/actonDev/s7-imgui/blob/master/docs/ns-doc.md