summaryrefslogtreecommitdiff
path: root/Master/texmf-dist/tex/context/base/char-utf.lua
blob: d0e40e664a681313f450be0d0937c2218cde67a6 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
if not modules then modules = { } end modules ['char-utf'] = {
    version   = 1.001,
    comment   = "companion to char-utf.mkiv",
    author    = "Hans Hagen, PRAGMA-ADE, Hasselt NL",
    copyright = "PRAGMA ADE / ConTeXt Development Team",
    license   = "see context related readme files"
}

--[[ldx--
<p>When a sequence of <l n='utf'/> characters enters the application, it may
be neccessary to collapse subsequences into their composed variant.</p>

<p>This module implements methods for collapsing and expanding <l n='utf'/>
sequences. We also provide means to deal with characters that are
special to <l n='tex'/> as well as 8-bit characters that need to end up
in special kinds of output (for instance <l n='pdf'/>).</p>

<p>We implement these manipulations as filters. One can run multiple filters
over a string.</p>
--ldx]]--

local concat, gmatch, gsub, find = table.concat, string.gmatch, string.gsub, string.find
local utfchar, utfbyte, utfcharacters, utfvalues = utf.char, utf.byte, utf.characters, utf.values
local allocate = utilities.storage.allocate
local lpegmatch, lpegpatterns = lpeg.match, lpeg.patterns

local charfromnumber = characters.fromnumber

-- todo: trackers
-- graphemes: basic symbols

characters            = characters or { }
local characters      = characters

characters.graphemes  = allocate()
local graphemes       = characters.graphemes

characters.combined   = allocate()
local combined        = characters.combined

characters.decomposed = allocate()
local decomposed      = characters.decomposed

characters.mathpairs  = allocate()
local mathpairs       = characters.mathpairs

characters.filters    = allocate()
local filters         = characters.filters

filters.utf           = filters.utf  or { }
local utffilters      = characters.filters.utf

-- is characters.combined cached?

--[[ldx--
<p>It only makes sense to collapse at runtime, since we don't expect
source code to depend on collapsing.</p>
--ldx]]--

-- for the moment, will be entries in char-def.lua

local decomposed = allocate {
    ["IJ"] = "IJ",
    ["ij"] = "ij",
    ["և"] = "եւ",
    ["ff"] = "ff",
    ["fi"] = "fi",
    ["fl"] = "fl",
    ["ffi"] = "ffi",
    ["ffl"] = "ffl",
    ["ſt"] = "ſt",
    ["st"] = "st",
    ["ﬓ"] = "մն",
    ["ﬔ"] = "մե",
    ["ﬕ"] = "մի",
    ["ﬖ"] = "վն",
    ["ﬗ"] = "մխ",
}

characters.decomposed = decomposed

local function initialize() -- maybe only 'mn'
    local data = characters.data
    for unicode, v in next, data do
        -- using vs and first testing for length is faster (.02->.01 s)
        local vs = v.specials
        local vc = vs and #vs == 3 and vs[1]
        if vc == "char" then
            local one, two = vs[2], vs[3]
            if data[two].category == "mn" then
                local cgf = combined[one]
                if not cgf then
                    cgf = { [two] = unicode }
                    combined[one]  = cgf
                else
                    cgf[two] = unicode
                end
            end
            local first, second, combination = utfchar(one), utfchar(two), utfchar(unicode)
            local cgf = graphemes[first]
            if not cgf then
                cgf = { [second] = combination }
                graphemes[first] = cgf
            else
                cgf[second] = combination
            end
            if v.mathclass or v.mathspec then
                local mps = mathpairs[two]
                if not mps then
                    mps = { [one] = unicode }
                    mathpairs[two] = mps
                else
                    mps[one] = unicode -- here unicode
                end
                local mps = mathpairs[second]
                if not mps then
                    mps = { [first] = combination }
                    mathpairs[second] = mps
                else
                    mps[first] = combination
                end
            end
     -- elseif vc == "compat" then
     -- else
     --     local description = v.description
     --     if find(description,"LIGATURE") then
     --         if vs then
     --             local t = { }
     --             for i=2,#vs do
     --                 t[#t+1] = utfchar(vs[i])
     --             end
     --             decomposed[utfchar(unicode)] = concat(t)
     --         else
     --             local vs = v.shcode
     --             if vs then
     --                 local t = { }
     --                 for i=1,#vs do
     --                     t[i] = utfchar(vs[i])
     --                 end
     --                 decomposed[utfchar(unicode)] = concat(t)
     --             end
     --         end
     --     end
        end
    end
    initialize = false
    characters.initialize = function() end -- when used outside tex
end

characters.initialize = initialize

-- utffilters.addgrapheme(utfchar(318),'l','\string~')
-- utffilters.addgrapheme('c','a','b')

function utffilters.addgrapheme(result,first,second) -- can be U+ 0x string or utf or number
    local result = charfromnumber(result)
    local first  = charfromnumber(first)
    local second = charfromnumber(second)
    if not graphemes[first] then
        graphemes[first] = { [second] = result }
    else
        graphemes[first][second] = result
    end
end

--[[ldx--
<p>In order to deal with 8-bit output, we need to find a way to
go from <l n='utf'/> to 8-bit. This is handled in the
<l n='luatex'/> engine itself.</p>

<p>This leaves us problems with characters that are specific to
<l n='tex'/> like <type>{}</type>, <type>$</type> and alike.</p>

<p>We can remap some chars that tex input files are sensitive for to
a private area (while writing to a utility file) and revert then
to their original slot when we read in such a file. Instead of
reverting, we can (when we resolve characters to glyphs) map them
to their right glyph there.</p>

<p>For this purpose we can use the private planes 0x0F0000 and
0x100000.</p>
--ldx]]--

local low     = allocate({ })
local high    = allocate({ })
local escapes = allocate({ })
local special = "~#$%^&_{}\\|"

local private = {
    low     = low,
    high    = high,
    escapes = escapes,
}

utffilters.private = private

local tohigh = lpeg.replacer(low)   -- frozen, only for basic tex
local tolow  = lpeg.replacer(high)  -- frozen, only for basic tex

lpegpatterns.utftohigh = tohigh
lpegpatterns.utftolow  = tolow

function utffilters.harden(str)
    return lpegmatch(tohigh,str)
end

function utffilters.soften(str)
    return lpegmatch(tolow,str)
end

local function set(ch)
    local cb
    if type(ch) == "number" then
        cb, ch = ch, utfchar(ch)
    else
        cb = utfbyte(ch)
    end
    if cb < 256 then
        escapes[ch] = "\\" .. ch
        low[ch] = utfchar(0x0F0000 + cb)
        if ch == "%" then
            ch = "%%" -- nasty, but we need this as in replacements (also in lpeg) % is interpreted
        end
        high[utfchar(0x0F0000 + cb)] = ch
    end
end

private.set = set

-- function private.escape (str) return    gsub(str,"(.)", escapes) end
-- function private.replace(str) return utfgsub(str,"(.)", low    ) end
-- function private.revert (str) return utfgsub(str,"(.)", high   ) end

private.escape  = utf.remapper(escapes)
private.replace = utf.remapper(low)
private.revert  = utf.remapper(high)

for ch in gmatch(special,".") do set(ch) end

--[[ldx--
<p>We get a more efficient variant of this when we integrate
replacements in collapser. This more or less renders the previous
private code redundant. The following code is equivalent but the
first snippet uses the relocated dollars.</p>

<typing>
[󰀤x󰀤] [$x$]
</typing>

<p>The next variant has lazy token collecting, on a 140 page mk.tex this saves
about .25 seconds, which is understandable because we have no graphmes and
not collecting tokens is not only faster but also saves garbage collecting.
</p>
--ldx]]--

-- lpeg variant is not faster
--
-- I might use the combined loop at some point for the filter
-- some day.

-- function utffilters.collapse(str) -- not really tested (we could preallocate a table)
--     if str and str ~= "" then
--         local nstr = #str
--         if nstr > 1 then
--             if initialize then -- saves a call
--                 initialize()
--             end
--             local tokens, t, first, done, n = { }, 0, false, false, 0
--             for second in utfcharacters(str) do
--                 local dec = decomposed[second]
--                 if dec then
--                     if not done then
--                         if n > 0 then
--                             for s in utfcharacters(str) do
--                                 if n == 1 then
--                                     break
--                                 else
--                                     t = t + 1
--                                     tokens[t] = s
--                                     n = n - 1
--                                 end
--                             end
--                         end
--                         done = true
--                     elseif first then
--                         t = t + 1
--                         tokens[t] = first
--                     end
--                     t = t + 1
--                     tokens[t] = dec
--                     first = false
--                 elseif done then
--                     local crs = high[second]
--                     if crs then
--                         if first then
--                             t = t + 1
--                             tokens[t] = first
--                         end
--                         first = crs
--                     else
--                         local cgf = graphemes[first]
--                         if cgf and cgf[second] then
--                             first = cgf[second]
--                         elseif first then
--                             t = t + 1
--                             tokens[t] = first
--                             first = second
--                         else
--                             first = second
--                         end
--                     end
--                 else
--                     local crs = high[second]
--                     if crs then
--                         for s in utfcharacters(str) do
--                             if n == 1 then
--                                 break
--                             else
--                                 t = t + 1
--                                 tokens[t] = s
--                                 n = n - 1
--                             end
--                         end
--                         if first then
--                             t = t + 1
--                             tokens[t] = first
--                         end
--                         first = crs
--                         done = true
--                     else
--                         local cgf = graphemes[first]
--                         if cgf and cgf[second] then
--                             for s in utfcharacters(str) do
--                                 if n == 1 then
--                                     break
--                                 else
--                                     t = t + 1
--                                     tokens[t] = s
--                                     n = n - 1
--                                 end
--                             end
--                             first = cgf[second]
--                             done = true
--                         else
--                             first = second
--                             n = n + 1
--                         end
--                     end
--                 end
--             end
--             if done then
--                 if first then
--                     t = t + 1
--                     tokens[t] = first
--                 end
--                 return concat(tokens) -- seldom called
--             end
--         elseif nstr > 0 then
--             return high[str] or str
--         end
--     end
--     return str
-- end

local skippable  = table.tohash { "mkiv", "mkvi" }
local filesuffix = file.suffix

-- we could reuse tokens but it's seldom populated anyway

function utffilters.collapse(str,filename) -- not really tested (we could preallocate a table)
    if skippable[filesuffix(filename)] then
        return str
    end
    if str and str ~= "" then
        local nstr = #str
        if nstr > 1 then
            if initialize then -- saves a call
                initialize()
            end
            local tokens, t, first, done, n = { }, 0, false, false, 0
            for second in utfcharacters(str) do
                if done then
                    local crs = high[second]
                    if crs then
                        if first then
                            t = t + 1
                            tokens[t] = first
                        end
                        first = crs
                    else
                        local cgf = graphemes[first]
                        if cgf and cgf[second] then
                            first = cgf[second]
                        elseif first then
                            t = t + 1
                            tokens[t] = first
                            first = second
                        else
                            first = second
                        end
                    end
                else
                    local crs = high[second]
                    if crs then
                        for s in utfcharacters(str) do
                            if n == 1 then
                                break
                            else
                                t = t + 1
                                tokens[t] = s
                                n = n - 1
                            end
                        end
                        if first then
                            t = t + 1
                            tokens[t] = first
                        end
                        first = crs
                        done = true
                    else
                        local cgf = graphemes[first]
                        if cgf and cgf[second] then
                            for s in utfcharacters(str) do
                                if n == 1 then
                                    break
                                else
                                    t = t + 1
                                    tokens[t] = s
                                    n = n - 1
                                end
                            end
                            first = cgf[second]
                            done = true
                        else
                            first = second
                            n = n + 1
                        end
                    end
                end
            end
            if done then
                if first then
                    t = t + 1
                    tokens[t] = first
                end
                return concat(tokens) -- seldom called
            end
        elseif nstr > 0 then
            return high[str] or str
        end
    end
    return str
end

function utffilters.decompose(str)
    if str and str ~= "" then
        local nstr = #str
        if nstr > 1 then
         -- if initialize then -- saves a call
         --     initialize()
         -- end
            local tokens, t, done, n = { }, 0, false, 0
            for s in utfcharacters(str) do
                local dec = decomposed[s]
                if dec then
                    if not done then
                        if n > 0 then
                            for s in utfcharacters(str) do
                                if n == 1 then
                                    break
                                else
                                    t = t + 1
                                    tokens[t] = s
                                    n = n - 1
                                end
                            end
                        end
                        done = true
                    end
                    t = t + 1
                    tokens[t] = dec
                elseif done then
                    t = t + 1
                    tokens[t] = s
                else
                    n = n + 1
                end
            end
            if done then
                return concat(tokens) -- seldom called
            end
        end
    end
    return str
end

local sequencers = utilities.sequencers

if sequencers then

    local textfileactions = resolvers.openers.helpers.textfileactions

    sequencers.appendaction (textfileactions,"system","characters.filters.utf.collapse")
    sequencers.disableaction(textfileactions,"characters.filters.utf.collapse")

    sequencers.appendaction (textfileactions,"system","characters.filters.utf.decompose")
    sequencers.disableaction(textfileactions,"characters.filters.utf.decompose")

    function characters.filters.utf.enable()
        sequencers.enableaction(textfileactions,"characters.filters.utf.collapse")
        sequencers.enableaction(textfileactions,"characters.filters.utf.decompose")
    end

    directives.register("filters.utf.collapse", function(v)
        sequencers[v and "enableaction" or "disableaction"](textfileactions,"characters.filters.utf.collapse")
    end)

    directives.register("filters.utf.decompose", function(v)
        sequencers[v and "enableaction" or "disableaction"](textfileactions,"characters.filters.utf.decompose")
    end)

end

--[[ldx--
<p>Next we implement some commands that are used in the user interface.</p>
--ldx]]--

-- commands = commands or { }
--
-- function commands.uchar(first,second)
--     context(utfchar(first*256+second))
-- end

--[[ldx--
<p>A few helpers (used to be <t>luat-uni<t/>).</p>
--ldx]]--

-- obsolete:
--
-- function utf.split(str)
--     local t, n = { }, 0
--     for snippet in utfcharacters(str) do
--         n = n + 1
--         t[n+1] = snippet
--     end
--     return t
-- end
--
-- function utf.each(str,fnc)
--     for snippet in utfcharacters(str) do
--         fnc(snippet)
--     end
-- end