summaryrefslogtreecommitdiff
path: root/pprint.lua
blob: efb3e2ee69b7d1face0b5857956e357c1951e2e4 (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
-- https://github.com/jagt/pprint.lua/blob/master/pprint.lua
-- public domain

local pprint = { VERSION = '0.1' }

local depth = 1

pprint.defaults = {
    -- If set to number N, then limit table recursion to N deep.
    depth_limit = false,
    -- type display trigger, hide not useful datatypes by default
    -- custom types are treated as table
    show_nil = true,
    show_boolean = true,
    show_number = true,
    show_string = true,
    show_table = true,
    show_function = false,
    show_thread = false,
    show_userdata = false,
    -- additional display trigger
    show_metatable = false,     -- show metatable
    show_all = false,           -- override other show settings and show everything
    use_tostring = false,       -- use __tostring to print table if available
    filter_function = nil,      -- called like callback(value[,key, parent]), return truty value to hide
    object_cache = 'local',     -- cache blob and table to give it a id, 'local' cache per print, 'global' cache
                                -- per process, falsy value to disable (might cause infinite loop)
    -- format settings
    indent_size = 2,            -- indent for each nested table level
    level_width = 80,           -- max width per indent level
    wrap_string = true,         -- wrap string when it's longer than level_width
    wrap_array = false,         -- wrap every array elements
    sort_keys = true,           -- sort table keys
}

local TYPES = {
    ['nil'] = 1, ['boolean'] = 2, ['number'] = 3, ['string'] = 4, 
    ['table'] = 5, ['function'] = 6, ['thread'] = 7, ['userdata'] = 8
}

-- seems this is the only way to escape these, as lua don't know how to map char '\a' to 'a'
local ESCAPE_MAP = {
    ['\a'] = '\\a', ['\b'] = '\\b', ['\f'] = '\\f', ['\n'] = '\\n', ['\r'] = '\\r',
    ['\t'] = '\\t', ['\v'] = '\\v', ['\\'] = '\\\\',
}

-- generic utilities
local function escape(s)
    s = s:gsub('([%c\\])', ESCAPE_MAP)
    local dq = s:find('"') 
    local sq = s:find("'")
    if dq and sq then
        return s:gsub('"', '\\"'), '"'
    elseif sq then
        return s, '"'
    else
        return s, "'"
    end
end

local function is_plain_key(key)
    return type(key) == 'string' and key:match('^[%a_][%a%d_]*$')
end

local CACHE_TYPES = {
    ['table'] = true, ['function'] = true, ['thread'] = true, ['userdata'] = true
}

-- cache would be populated to be like:
-- {
--     function = { `fun1` = 1, _cnt = 1 }, -- object id
--     table = { `table1` = 1, `table2` = 2, _cnt = 2 },
--     visited_tables = { `table1` = 7, `table2` = 8  }, -- visit count
-- }
-- use weakrefs to avoid accidentall adding refcount
local function cache_apperance(obj, cache, option)
    if not cache.visited_tables then
        cache.visited_tables = setmetatable({}, {__mode = 'k'})
    end
    local t = type(obj)

    -- TODO can't test filter_function here as we don't have the ix and key,
    -- might cause different results?
    -- respect show_xxx and filter_function to be consistent with print results
    if (not TYPES[t] and not option.show_table)
        or (TYPES[t] and not option['show_'..t]) then
        return
    end

    if CACHE_TYPES[t] or TYPES[t] == nil then
        if not cache[t] then
            cache[t] = setmetatable({}, {__mode = 'k'})
            cache[t]._cnt = 0
        end
        if not cache[t][obj] then
            cache[t]._cnt = cache[t]._cnt + 1
            cache[t][obj] = cache[t]._cnt
        end
    end
    if t == 'table' or TYPES[t] == nil then
        if cache.visited_tables[obj] == false then
            -- already printed, no need to mark this and its children anymore
            return
        elseif cache.visited_tables[obj] == nil then
            cache.visited_tables[obj] = 1
        else
            -- visited already, increment and continue
            cache.visited_tables[obj] = cache.visited_tables[obj] + 1
            return
        end
        for k, v in pairs(obj) do
            cache_apperance(k, cache, option)
            cache_apperance(v, cache, option)
        end
        local mt = getmetatable(obj)
        if mt and option.show_metatable then
            cache_apperance(mt, cache, option)
        end
    end
end

-- makes 'foo2' < 'foo100000'. string.sub makes substring anyway, no need to use index based method
local function str_natural_cmp(lhs, rhs)
    while #lhs > 0 and #rhs > 0 do
        local lmid, lend = lhs:find('%d+')
        local rmid, rend = rhs:find('%d+')
        if not (lmid and rmid) then return lhs < rhs end

        local lsub = lhs:sub(1, lmid-1)
        local rsub = rhs:sub(1, rmid-1)
        if lsub ~= rsub then
            return lsub < rsub
        end
        
        local lnum = tonumber(lhs:sub(lmid, lend))
        local rnum = tonumber(rhs:sub(rmid, rend))
        if lnum ~= rnum then
            return lnum < rnum
        end

        lhs = lhs:sub(lend+1)
        rhs = rhs:sub(rend+1)
    end
    return lhs < rhs
end

local function cmp(lhs, rhs)
    local tleft = type(lhs)
    local tright = type(rhs)
    if tleft == 'number' and tright == 'number' then return lhs < rhs end
    if tleft == 'string' and tright == 'string' then return str_natural_cmp(lhs, rhs) end
    if tleft == tright then return str_natural_cmp(tostring(lhs), tostring(rhs)) end

    -- allow custom types
    local oleft = TYPES[tleft] or 9
    local oright = TYPES[tright] or 9
    return oleft < oright
end

-- setup option with default
local function make_option(option)
    if option == nil then
        option = {}
    end
    for k, v in pairs(pprint.defaults) do
        if option[k] == nil then
            option[k] = v
        end
        if option.show_all then
            for t, _ in pairs(TYPES) do
                option['show_'..t] = true
            end
            option.show_metatable = true
        end
    end
    return option
end

-- override defaults and take effects for all following calls
function pprint.setup(option)
    pprint.defaults = make_option(option)
end

-- format lua object into a string
function pprint.pformat(obj, option, printer)
    option = make_option(option)
    local buf = {}
    local function default_printer(s)
        table.insert(buf, s)
    end
    printer = printer or default_printer

    local cache
    if option.object_cache == 'global' then
        -- steal the cache into a local var so it's not visible from _G or anywhere
        -- still can't avoid user explicitly referentce pprint._cache but it shouldn't happen anyway
        cache = pprint._cache or {}
        pprint._cache = nil
    elseif option.object_cache == 'local' then
        cache = {}
    end

    local last = '' -- used for look back and remove trailing comma
    local status = {
        indent = '', -- current indent
        len = 0,     -- current line length
    }

    local wrapped_printer = function(s)
        printer(last)
        last = s
    end

    local function _indent(d)
        status.indent = string.rep(' ', d + #(status.indent))
    end

    local function _n(d)
        wrapped_printer('\n')
        wrapped_printer(status.indent)
        if d then
            _indent(d)
        end
        status.len = 0
        return true -- used to close bracket correctly
    end

    local function _p(s, nowrap)
        status.len = status.len + #s
        if not nowrap and status.len > option.level_width then
            _n()
            wrapped_printer(s)
            status.len = #s
        else
            wrapped_printer(s)
        end
    end

    local formatter = {}
    local function format(v)
        local f = formatter[type(v)]
        f = f or formatter.table -- allow patched type()
        if option.filter_function and option.filter_function(v, nil, nil) then
            return ''
        else
            return f(v)
        end
    end

    local function tostring_formatter(v)
        return tostring(v)
    end

    local function number_formatter(n)
        return n == math.huge and '[[math.huge]]' or tostring(n)
    end

    local function nop_formatter(v)
        return ''
    end

    local function make_fixed_formatter(t, has_cache)
        if has_cache then
            return function (v)
                return string.format('[[%s %d]]', t, cache[t][v])
            end
        else
            return function (v)
                return '[['..t..']]'
            end
        end
    end

    local function string_formatter(s, force_long_quote)
        local s, quote = escape(s)
        local quote_len = force_long_quote and 4 or 2
        if quote_len + #s + status.len > option.level_width then
            _n()
            -- only wrap string when is longer than level_width
            if option.wrap_string and #s + quote_len > option.level_width then
                -- keep the quotes together
                _p('[[')
                while #s + status.len >= option.level_width do
                    local seg = option.level_width - status.len
                    _p(string.sub(s, 1, seg), true)
                    _n()
                    s = string.sub(s, seg+1)
                end
                _p(s) -- print the remaining parts
                return ']]' 
            end
        end

        return force_long_quote and '[['..s..']]' or quote..s..quote
    end

    local function table_formatter(t)
        if option.use_tostring then
            local mt = getmetatable(t)
            if mt and mt.__tostring then
                -- return string_formatter(tostring(t), true)
                return tostring(t)
            end
        end

        local print_header_ix = nil
        local ttype = type(t)
        if option.object_cache then
            local cache_state = cache.visited_tables[t]
            local tix = cache[ttype][t]
            -- FIXME should really handle `cache_state == nil`
            -- as user might add things through filter_function
            if cache_state == false then
                -- already printed, just print the the number
                return string_formatter(string.format('%s %d', ttype, tix), true)
            elseif cache_state > 1 then
                -- appeared more than once, print table header with number
                print_header_ix = tix
                cache.visited_tables[t] = false
            else
                -- appeared exactly once, print like a normal table
            end
        end

        local limit = tonumber(option.depth_limit)
        if limit and depth > limit then
           if print_header_ix then
              return string.format('[[%s %d]]...', ttype, print_header_ix)
           end
           return string_formatter(tostring(t), true)
        end

        local tlen = #t
        local wrapped = false
        _p('{')
        _indent(option.indent_size)
        _p(string.rep(' ', option.indent_size - 1))
        if print_header_ix then
            _p(string.format('--[[%s %d]] ', ttype, print_header_ix))
        end
        for ix = 1,tlen do
            local v = t[ix]
            if formatter[type(v)] == nop_formatter or 
               (option.filter_function and option.filter_function(v, ix, t)) then
               -- pass
            else
                if option.wrap_array then
                    wrapped = _n()
                end
                depth = depth+1
                _p(format(v)..', ')
                depth = depth-1
            end
        end

        -- hashmap part of the table, in contrast to array part
        local function is_hash_key(k)
            if type(k) ~= 'number' then
                return true
            end

            local numkey = math.floor(tonumber(k))
            if numkey ~= k or numkey > tlen or numkey <= 0 then
                return true
            end
        end

        local function print_kv(k, v, t)
            -- can't use option.show_x as obj may contain custom type
            if formatter[type(v)] == nop_formatter or
               formatter[type(k)] == nop_formatter or 
               (option.filter_function and option.filter_function(v, k, t)) then
                return
            end
            wrapped = _n()
            if is_plain_key(k) then
                _p(k, true)
            else
                _p('[')
                -- [[]] type string in key is illegal, needs to add spaces inbetween
                local k = format(k)
                if string.match(k, '%[%[') then
                    _p(' '..k..' ', true)
                else
                    _p(k, true)
                end
                _p(']')
            end
            _p(' = ', true)
            depth = depth+1
            _p(format(v), true)
            depth = depth-1
            _p(',', true)
        end

        if option.sort_keys then
            local keys = {}
            for k, _ in pairs(t) do
                if is_hash_key(k) then
                    table.insert(keys, k)
                end
            end
            table.sort(keys, cmp)
            for _, k in ipairs(keys) do
                print_kv(k, t[k], t)
            end
        else
            for k, v in pairs(t) do
                if is_hash_key(k) then
                    print_kv(k, v, t)
                end
            end
        end

        if option.show_metatable then
            local mt = getmetatable(t)
            if mt then
                print_kv('__metatable', mt, t)
            end
        end

        _indent(-option.indent_size)
        -- make { } into {}
        last = string.gsub(last, '^ +$', '')
        -- peek last to remove trailing comma
        last = string.gsub(last, ',%s*$', ' ')
        if wrapped then
            _n()
        end
        _p('}')

        return ''
    end

    -- set formatters
    formatter['nil'] = option.show_nil and tostring_formatter or nop_formatter
    formatter['boolean'] = option.show_boolean and tostring_formatter or nop_formatter
    formatter['number'] = option.show_number and number_formatter or nop_formatter -- need to handle math.huge
    formatter['function'] = option.show_function and make_fixed_formatter('function', option.object_cache) or nop_formatter
    formatter['thread'] = option.show_thread and make_fixed_formatter('thread', option.object_cache) or nop_formatter
    formatter['userdata'] = option.show_userdata and make_fixed_formatter('userdata', option.object_cache) or nop_formatter
    formatter['string'] = option.show_string and string_formatter or nop_formatter
    formatter['table'] = option.show_table and table_formatter or nop_formatter

    if option.object_cache then
        -- needs to visit the table before start printing
        cache_apperance(obj, cache, option)
    end

    _p(format(obj))
    printer(last) -- close the buffered one

    -- put cache back if global
    if option.object_cache == 'global' then
        pprint._cache = cache
    end

    return table.concat(buf)
end

-- pprint all the arguments
function pprint.pprint( ... )
    local args = {...}
    -- select will get an accurate count of array len, counting trailing nils
    local len = select('#', ...)
    for ix = 1,len do
        pprint.pformat(args[ix], nil, io.write)
        io.write('\n')
    end
end

setmetatable(pprint, {
    __call = function (_, ...)
        pprint.pprint(...)
    end
})

return pprint