Commit 0589a302 authored by Daniel Kochmański's avatar Daniel Kochmański

Initial commit

Signed-off-by: Daniel Kochmański's avatarDaniel Kochmański <daniel@turtleware.eu>
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* Introduction
=TRANSLATE= is a thin abstraction layer over the ordinary strings
which allows creation of a seamless translation for your
project. Code is written in a plain Common Lisp without any
dependencies. System definition is provided in =ASD= format,
although =ASDF= isn't required to run this software.
Library is licensed under =LLGPLv2=, what means that it may be used
in any project for any purpose although any significant
modifications to the library should be published. It doesn't impose
it's license on software depending on it.
To illustrate library usage some imaginary functions are used:
=MAKE-BUTTON= and =MAKE-LABEL=. The following sample code convention
is used:
- lines predated with ==> indicate *reader* input
- all other lines represent *printer* output
* Description
** Basic usage
Library pollutes =*READTABLE*= with dispatch macro character =#t=,
where "t" is abbreviation of "translate". User instead of writing
bare strings in his/her application, predates them with =#t=:
#+BEGIN_SRC common-lisp
==> #t"dum dum, piję rum"
"la la, I drink in the spa"
#+END_SRC
If =TRANSLATE:*LANGUAGE*= is bound to =NIL= and
=TRANSLATE:*RESOLUTION-TIME*= to =:LOAD-TIME=, then =#t="hello" will
resolve to the string "hello" and translation will have no
effect. It is convenient, because programmer can put =#t="strings"
for the future translation with no functional consequences at the
run-time while keeping application innards visually separated from
the messages meant to be presented to user.
#+BEGIN_SRC common-lisp
==> (setf translate:*language* nil)
==> (make-button :label #t"hello")
#<button "hello">
#+END_SRC
Binding =TRANSLATE:*LANGUAGE*= to non-NIL value enables string
translation. If no translation exists it will be temporarily
translated to the same value enclosed in a curly brackets:
#+BEGIN_SRC common-lisp
==> (translate:define-language :pl)
(#<hash-table 00000000054323c0> NIL #<compiled-function 0000000005fe08c0>)
==> (setf translate:*language* :pl)
:PL
==> (make-label :text #t"Greetings, programs")
;;; Warning: phrase "Greetings, programs" isn't defined for language :PL.
#<label "{Greetings, programs}">
==> (make-label :text #t"Leave the grid")
;;; Warning: phrase "Leave the grid" isn't defined for language :PL.
#<label "{Leave the grid}">
#+END_SRC
Using not translated string will cause a warning at the resolution
time and string will be added to the special list of phrases not
yet translated (which may be evaluated for the future processing,
like adding the missing translations). If a language put in the
=TRANSLATE:*LANGUAGE*= isn't defined yet, =CERROR= will be
signalled with a restart allowing language creation.
To distinguish dictionaries predicate =EQL= is used and phrases are
distinguished using predicate =EQUAL=, so the most convenient is
using symbols as the language designators. It also implies, that
phrases meant for translation are case sensitive.
** Adding translation
To add translations two interfaces are
provided. =ADD-SINGLE-TRANSLATION= function takes three arguments,
where the first is the language for which we provide translation,
the second is a translated phrase and the third is an actual
translation. Phrase type must be a string, but the translation
might be any kind of object (although it is advised to use strings
user is free to shoot himself in the foot by abusing the
translation mechanism).
#+BEGIN_SRC lisp
==> (translate:add-single-translation 'pl "hello" "Witaj!")
;;; Warning: Implicitly creating language PL.
[PL] hello -> Witaj!
"Witaj!"
==> (translate:add-single-translation 'en "hello" "Welcome!")
;;; Warning: Implicitly creating language EN.
[EN] hello -> Welcome!
"Welcome!"
==> (translate:add-single-translation
'pl "bang"
(let ((i 1))
(lambda ()
(format nil "bah ~A" (incf i)))))
bang -> #<bytecompiled-closure #<bytecompiled-function 00000000067d9f50>> (PL)
#<bytecompiled-closure #<bytecompiled-function 00000000067d9f50>>
#+END_SRC
=ADD-TRANSLATIONS= is a simple wrapper around
=ADD-SINGLE-TRANSLATION= that allows translating multiple phrases
in one form. The first argument is once again the translation
language, while all further arguments are alternately phrases and
translations.
#+BEGIN_SRC lisp
==> (translate:add-translations 'pl
"header-about" "O firmie"
"header-offer" "Oferta"
"header-blog" "Blog"
"header-pricing" "Cennik"
"header-contact" "Kontakt")
[PL] header-about -> O firmie
[PL] header-offer -> Oferta
[PL] header-blog -> Blog
[PL] header-pricing -> Cennik
[PL] header-contact -> Kontakt
T
==> (translate:add-translations 'en
"header-about" "About"
"header-offer" "Offer"
"header-blog" "Blog"
"header-pricing" "Prices"
"header-contact" "Contact")
[EN] header-about -> About
[EN] header-offer -> Offer
[EN] header-blog -> Blog
[EN] header-pricing -> Prices
[EN] header-contact -> Contact
T
#+END_SRC
Generally it is advised to use symbolic and meaningful names for
phrases to be translated, not the final phrases written in English.
Providing "translation-tags" of concise form is easier to
comprehend for people, who will translate the application.
** Interactive fixing of the missing phrases
Loading the code is enough to catch all not yet translated phrases
for the active language (bound to =TRANSLATE:*LANGUAGE*=) if
resolution is performed at load time. Otherwise not translated
phrase is saved after it's first evaluation. To list saved phrases
without translations function =MISSING-TRANSLATIONS= is
available. It returns a list of form ={((LANG (PHRASES*))*)}=.
#+BEGIN_SRC lisp
==> (missing-translations)
((PL ("phrase-1" "phrase-2" "phrase-3"))
(BG ("phrase-1" "phrase-3")))
#+END_SRC
Such output means, that language =PL= doesn't have translations for
"phrase-1", "phrase-2" and "phrase-3", while =BG= doesn't have
translations for "phrase-1" and "phrase-3". Languages, which have
all translations are filtered and they don't appear in the result.
** Different times of the resolution
Library may work in two different modes which dictate time, when
the actual translation is performed. Strings may be translated at
the load-time, or at the run-time.
First approach is faster, because it doesn't require any processing
at the run-time, while the second is much more flexible allowing
changing dictionaries and translations when the program is running
or per- lexical scope basis.
It is important to remember, that when translations are done at the
run-time, strings predated by =#t= are transformed to function calls
and they may work not as expected in the context, where enclosing
macro prevents their evaluation.
#+BEGIN_SRC common-lisp
==> (setf translate:*mode* :run-time)
:RUN-TIME
==> (setf translate:*language* :en)
:EN
==> (translate:add-single-translation :en "hello" "Hello")
[EN] hello -> Hello
==> (translate:add-single-translation :pl "hello" "Cześć")
[PL] hello -> Cześć
==> (let ((translate:*language* :en))
#t"hello")
"Hello"
==> (let ((translate:*language* :pl))
#t"hello")
"Cześć"
==> (quote #t"hello")
(TRANSLATE:TRANSLATE "hello")
#+END_SRC
When translation is performed at the load-time it has to be present
before actual phrase is used (i.e. in lambda expression), because
phrases are resolved to their translations immediately. That also
means, that changing =*LANGUAGE*= in the future won't affect
translations resolved earlier.
#+BEGIN_SRC common-lisp
==> (setf translate:*mode* :load-time)
:RUN-TIME
==> (setf translate:*language* :en)
:EN
==> (defparameter *my-function-1*
(lambda () #t"hello"))
;;; Warning: phrase "hello" isn't defined for language EN.
,*MY-FUNCTION-1*
==> (translate:add-translation :en "hello" "Hello")
hello -> Hello (EN)
==> (translate:add-translation :pl "hello" "Cześć")
hello -> Cześć (PL)
==> (let ((*language* :en))
#t"hello")
"Hello"
==> (let ((*language* :pl)) ; lexical scope is ignored
#t"hello")
"Hello"
==> (defparameter *my-function-2*
(lambda () #t"hello"))
,*MY-FUNCTION-2*
==> (funcall *my-function-1*) ; phrase wasn't translated when function was created
"{hello}"
==> (funcall *my-function-2*)
"Hello"
==> (quote #t"hello")
"Hello"
#+END_SRC
Translation at run-time is better when programmer wants to add
translations ad-hoc or wants to switch languages when application
is running. Load-time translation is more suitable for static
translations for deployed applications or where macros prevent
necessary evaluation of the expressions. Also when programmer wants
to add translations in the future (if language is bound to nil and
resolution is performed at load-time the expression =#t="hello
world" means the same as the "hello world".
* Reference
** Parameters
*** *LANGUAGE*
This variable holds the current language designator (predicate
used for comparison is =EQL=). If bound to =NIL=, translation
works the same way as =IDENTITY= function.
*** *RESOLUTION-TIME
Applicable values are =:LOAD-TIME= and =:RUN-TIME= (the latter is
default). The variable controls time of actual resolution.
If it's the =:LOAD-TIME=, then resolution is performed when the
reader encounters =#t= dispatch macro character, while setting the
variable to =:RUN-TIME= translates =#t="string" to form
=(TRANSLATE "string")= and resolution takes place at the time of
the form evaluation.
** Functions
*** DEFINE-LANGUAGE
#+BEGIN_SRC text
DEFINE-LANGUAGE - external symbol in TRANSLATE package
-----------------------------------------------------------------------------
DEFINE-LANGUAGE (NAME &REST TRANSLATIONS) [Function]
Define language NAME with provided TRANSLATIONS
If LANGUAGE exists continuable error is signalled, which allows either
dropping the operation or superseeding already defined language.
TRANSLATIONS are alternatery phrases and their corresponding objects.
-----------------------------------------------------------------------------
#+END_SRC
*** ADD-SINGLE-TRANSLATION
#+BEGIN_SRC text
ADD-SINGLE-TRANSLATION - external symbol in TRANSLATE package
-----------------------------------------------------------------------------
ADD-SINGLE-TRANSLATION (LANGUAGE PHRASE TRANSLATION) [Function]
Add TRANSLATION of PHRASE for given LANGUAGE
If LANGUAGE doesn't exist it is implicitly created and the warning is
emited.
-----------------------------------------------------------------------------
#+END_SRC
*** ADD-TRANSLATIONS
#+BEGIN_SRC text
ADD-TRANSLATIONS - external symbol in TRANSLATE package
-----------------------------------------------------------------------------
ADD-TRANSLATIONS (LANGUAGE &REST TRANSLATIONS) [Function]
Add any number of TRANSLATIONS for given LANGUAGE
-----------------------------------------------------------------------------
#+END_SRC
*** TRANSLATE
#+BEGIN_SRC text
TRANSLATE - external symbol in TRANSLATE package
-----------------------------------------------------------------------------
TRANSLATE (PHRASE &OPTIONAL (LANGUAGE *LANGUAGE*)) [Function]
Find translation of PHRASE in the store associated with LANGUAGE
If LANGUAGE is NIL, then this is the same as the IDENTITY function. If
provided LANGUAGE isn't defined the store is explicitly created. If no
PHRASE is defined for a given language, it is stored for later
translation and replaced by PHRASE surrunded by curly brackets.
-----------------------------------------------------------------------------
#+END_SRC
*** MISSING-TRANSLATIONS
#+BEGIN_SRC text
MISSING-TRANSLATIONS - external symbol in TRANSLATE package
-----------------------------------------------------------------------------
MISSING-TRANSLATIONS [Function]
Creates list of phrases which aren't translated for defined
languages. Retruns list of form: ({(LANG ({PHRASE}*))}*)
-----------------------------------------------------------------------------
#+END_SRC
;;;; package.lisp
(defpackage #:translate
(:use #:cl))
(in-package :translate)
(export '(*language*
*resolution-time*
define-language
add-single-translation
add-translations
translate
missing-translations))
;;;; cl-translate.asd
(asdf:defsystem #:translate
:name "translate"
:version "0.1.0"
:description "Abstraction layer for translations"
:author "Daniel 'jackdaniel' Kochmański <daniel@turtleware.eu>"
:license "LLGPLv2"
:homepage "https://gitlab.common-lisp.net/dkochmanski/translate"
:serial t
:depends-on ()
:components ((:file "package")
(:file "translate")))
;;;; cl-translate.lisp
(in-package #:translate)
;; global variables
(defparameter *language* nil
"Language for which the translation is done")
(defparameter *translations* nil
"Table containing further translation tables")
(defparameter *resolution-time* :run-time
"Controlls translation resulution time - maybe be either :run-time
or :load-time")
;; creation
(defun define-language (name &rest translations)
"Define language NAME with provided TRANSLATIONS
If LANGUAGE exists continuable error is signalled, which allows either
dropping the operation or superseeding already defined language.
TRANSLATIONS are alternatery phrases and their corresponding objects."
(when (getf *translations* name)
(cerror "Supersede language."
"Language ~A is already defined." name))
(setf (getf *translations* name)
(list (make-hash-table :test 'equal)
nil
#'(lambda (str)
(concatenate 'string
"{" str "}"))))
(apply #'add-translations name translations))
(defun add-single-translation (language phrase translation)
"Add TRANSLATION of PHRASE for given LANGUAGE
If LANGUAGE doesn't exist it is implicitly created and the warning is
emited."
(check-type phrase string)
(let ((dict (car (or (getf *translations* language)
(progn
(warn "Implicitly creating language ~A." language)
(define-language language)
(getf *translations* language))))))
(format t "[~a] ~a -> ~a~%" language phrase translation)
(setf (gethash phrase dict) translation)))
(defun add-translations (language &rest translations)
"Add any number of TRANSLATIONS for given LANGUAGE"
(do* ((tr translations (cddr tr)))
((endp tr) T)
(destructuring-bind (phrase trans &rest ign) tr
(declare (ignore ign))
(add-single-translation language phrase trans))))
;; resolution
(defun translate (phrase &optional (language *language*))
"Find translation of PHRASE in the store associated with LANGUAGE
If LANGUAGE is NIL, then this is the same as the IDENTITY function. If
provided LANGUAGE isn't defined the store is explicitly created. If no
PHRASE is defined for a given language, it is stored for later
translation and replaced by PHRASE surrunded by curly brackets."
(check-type phrase string)
(if language
(let ((lang
(or (getf *translations* language)
(progn (cerror "Create language."
"Language ~A doesn't exist." language)
(define-language language)
(getf *translations* language)))))
(destructuring-bind (dictionary missing missing-fn) lang
(declare (ignore missing))
(multiple-value-bind (result found?)
(gethash phrase dictionary
(funcall missing-fn phrase))
(unless found?
(pushnew phrase (second lang) :test 'equal)
(warn "Phrase \"~A\" isn't defined for language ~A."
phrase language))
result)))
phrase))
(set-dispatch-macro-character
#\# #\t
#'(lambda (stream char1 char2)
(declare (ignore char1 char2))
(let ((phrase (read stream)))
(check-type phrase string)
(if (eql *resolution-time* :load-time)
(translate phrase)
`(translate ,phrase)))))
;; missing translations
(defun missing-translations ()
"Creates list of phrases which aren't translated for defined
languages. Retruns list of form: ({(LANG ({PHRASE}*))}*)"
(do* (acc
(reminder *translations* (cddr reminder))
(elt (second (cadr reminder))
(second (cadr reminder))))
((null reminder) acc)
(when elt
(push (list (car reminder)
elt)
acc))))
#+(or)
(defun missing-translations-template ()
`(block nil
,@(let (acc)
(dolist (tr (missing-translations) acc)
(push
`(add-translations ,(car tr)
,@(mapcar #'(lambda (elt)
(list elt "{FILL-ME}"))
(second tr)))
acc)))))
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