json.bend
bend-kit-json@0.5.0.1 · 925 lines · 0 definitions
1# JSON values, parsed and encoded as RFC 8259. Source: https://github.com/paymog/bend-kit/tree/main/json
2import Base
3import bend-kit-bytes@0.3.0.0/bytes.bend as Bytes
4
5# JSON (RFC 8259) as UTF-8 in Bytes. Strings, numbers and object keys are
6# UTF-8 Bytes too. Nesting has no depth limit other than input size: the parser
7# keeps its own stack, since a Bend def cannot call itself through another def.
8# import ./json/json.bend as Json
9
10# Num keeps the number's exact text, so no precision is lost. Obj keeps its
11# fields in document order, repeated keys included.
12type Val is Type:
13 Null{}
14 Flag{on: Bool}
15 Num{s: Bytes.Bytes}
16 Str{s: Bytes.Bytes}
17 Arr{xs: List<&1, Val>}
18 Obj{kvs: List<&1, Bytes.Bytes & Val>}
19
20# An open container: array items so far, object fields so far, or those fields
21# and the key whose value comes next. Items and fields are reversed.
22type Open is Type:
23 OArr{xs: List<&1, Val>}
24 OObj{kvs: List<&1, Bytes.Bytes & Val>}
25 OKey{kvs: List<&1, Bytes.Bytes & Val>, key: Bytes.Bytes}
26
27# Writer
28# ------
29# Octets being written: the buffer, its size in words, the count so far, and
30# the word being filled. Bytes enter at the top of w, as in Bytes.from_string.
31type W is Type:
32 W{buf: Array<U32>, cap: U32, n: U32, w: U32}
33
34# The buffer doubles when word k does not fit.
35def w.room(grow: Bool, buf: Array<U32>, +k: U32) -> Array<U32>:
36 match grow:
37 case True{}:
38 Bytes.grow((k * 4 : U32), buf, (k * 8 : U32))
39 case False{}:
40 buf
41
42def w.store(full: Bool, buf: Array<U32>, +cap: U32, +n: U32, +w: U32) -> W:
43 match full:
44 case True{}:
45 +k = (n >> 2n : U32)
46 +g = U32.is_eq(k, cap)
47 W{Array.set(U32, w.room(g, buf, k), k, w), Bool.pick(U32, g, (cap * 2 : U32), cap), (n + 1 : U32), 0}
48 case False{}:
49 W{buf, cap, (n + 1 : U32), w}
50
51def w.put(o: W, +b: U32) -> W:
52 W{buf, +cap, +n, +w} = o
53 w.store(U32.is_eq((n .&. 3 : U32), 3), buf, cap, n, ((w >> 8n) .|. (b << 24n) : U32))
54
55def w.shrink(fit: Bool, +n: U32, buf: Array<U32>) -> Array<U32>:
56 match fit:
57 case True{}:
58 buf
59 case False{}:
60 Bytes.dst(Bytes.copy(n, buf, Bytes.alloc(n), 0, 0))
61
62# Stores the last partial word, then copies into the fewest words, as Bytes requires.
63def w.done(o: W) -> Bytes.Bytes:
64 W{buf, +cap, +n, +w} = o
65 +r = (n .&. 3 : U32)
66 +k = (n >> 2n : U32)
67 +g = U32.is_ne(r, 0) && U32.is_eq(k, cap)
68 +cap2 = Bool.pick(U32, g, (cap * 2 : U32), cap)
69 out = Bytes.flush(U32.is_ne(r, 0), w.room(g, buf, k), k, U32.shrn(w, U32.to_nat((((4 - r) .&. 3) * 8 : U32))))
70 Bytes.Bytes{n, w.shrink(U32.is_eq(U32.shln(1, Bytes.depth(Bytes.words(n))), cap2), n, out)}
71
72def w.cont(+c: U32, +k: Nat) -> U32:
73 (128 + (U32.shrn(c, k) .&. 63) : U32)
74
75def w.cp.of(+n: U32, +c: U32, o: W) -> W:
76 match n:
77 case 1:
78 w.put(o, c)
79 case 2:
80 w.put(w.put(o, (192 + U32.shrn(c, 6n) : U32)), w.cont(c, 0n))
81 case 3:
82 w.put(w.put(w.put(o, (224 + U32.shrn(c, 12n) : U32)), w.cont(c, 6n)), w.cont(c, 0n))
83 case _:
84 w.put(w.put(w.put(w.put(o, (240 + U32.shrn(c, 18n) : U32)), w.cont(c, 12n)), w.cont(c, 6n)), w.cont(c, 0n))
85
86# One code point in UTF-8.
87def w.cp(+c: U32, o: W) -> W:
88 w.cp.of(Bool.pick(U32, U32.is_lt(c, 128), 1, Bool.pick(U32, U32.is_lt(c, 2048), 2, Bool.pick(U32, U32.is_lt(c, 65536), 3, 4))), c, o)
89
90def w.hex(+n: U32) -> U32:
91 Bool.pick(U32, U32.is_lt(n, 10), (48 + n : U32), (87 + n : U32))
92
93def w.new() -> W:
94 W{Bytes.alloc(0), 1, 0, 0}
95
96def w.of.at(+len: U32, +cap: U32, r: Array<U32> & U32) -> W:
97 (buf, +v) = r
98 +m = (len .&. 3 : U32)
99 W{buf, cap, len, Bool.pick(U32, U32.is_eq(m, 0), 0, U32.shln(v, U32.to_nat(((4 - m) * 8 : U32))))}
100
101# A writer that appends to b.
102def w.of(b: Bytes.Bytes) -> W:
103 Bytes.Bytes{+len, buf} = b
104 w.of.at(len, U32.shln(1, Bytes.depth(Bytes.words(len))), Array.get(U32, buf, (len >> 2n : U32)))
105
106def w.text(s: String, o: W) -> W:
107 match s:
108 case SNil{}:
109 o
110 case SCon{Chr{+c}, t}:
111 w.text(t, w.cp(c, o))
112
113# Text, one Char per code point, as UTF-8.
114def utf8(s: String) -> Bytes.Bytes:
115 w.done(w.text(s, w.new()))
116
117# Numbers (§6)
118# ------------
119# States: 0 start, 1 after "-", 2 after a leading "0", 3 int digits, 4 after
120# ".", 5 fraction digits, 6 after "e", 7 after the exponent sign, 8 exponent
121# digits. 99 means the char does not continue the number.
122
123def digit(+c: U32) -> Bool:
124 Bool.and(U32.is_le(48, c), U32.is_le(c, 57))
125
126def num.trans(+st: U32, +c: U32) -> U32:
127 +d = digit(c)
128 +z = U32.is_eq(c, 48)
129 +dot = U32.is_eq(c, 46)
130 +e = Bool.or(U32.is_eq(c, 101), U32.is_eq(c, 69))
131 +sign = Bool.or(U32.is_eq(c, 43), U32.is_eq(c, 45))
132 Bool.pick(U32, U32.is_eq(st, 0), Bool.pick(U32, U32.is_eq(c, 45), 1, Bool.pick(U32, z, 2, Bool.pick(U32, d, 3, 99))),
133 Bool.pick(U32, U32.is_eq(st, 1), Bool.pick(U32, z, 2, Bool.pick(U32, d, 3, 99)),
134 Bool.pick(U32, Bool.or(U32.is_eq(st, 2), U32.is_eq(st, 3)), Bool.pick(U32, Bool.and(d, U32.is_eq(st, 3)), 3, Bool.pick(U32, dot, 4, Bool.pick(U32, e, 6, 99))),
135 Bool.pick(U32, Bool.or(U32.is_eq(st, 4), U32.is_eq(st, 5)), Bool.pick(U32, d, 5, Bool.pick(U32, Bool.and(e, U32.is_eq(st, 5)), 6, 99)),
136 Bool.pick(U32, U32.is_eq(st, 6), Bool.pick(U32, sign, 7, Bool.pick(U32, d, 8, 99)),
137 Bool.pick(U32, Bool.or(U32.is_eq(st, 7), U32.is_eq(st, 8)), Bool.pick(U32, d, 8, 99), 99))))))
138
139def num.accepts(+st: U32) -> Bool:
140 Bool.or(Bool.or(U32.is_eq(st, 2), U32.is_eq(st, 3)), Bool.or(U32.is_eq(st, 5), U32.is_eq(st, 8)))
141
142# Strings (§7)
143# ------------
144
145def hexd(+c: U32) -> U32:
146 Bool.pick(U32, digit(c), (c - 48 : U32), Bool.pick(U32, Bool.and(U32.is_le(97, c), U32.is_le(c, 102)), (c - 87 : U32), Bool.pick(U32, Bool.and(U32.is_le(65, c), U32.is_le(c, 70)), (c - 55 : U32), 99)))
147
148def is_hi(+v: U32) -> Bool:
149 Bool.and(U32.is_le(55296, v), U32.is_le(v, 56319))
150
151def is_lo(+v: U32) -> Bool:
152 Bool.and(U32.is_le(56320, v), U32.is_le(v, 57343))
153
154def esc.simple(+e: U32) -> U32:
155 Bool.pick(U32, U32.is_eq(e, 34), 34, Bool.pick(U32, U32.is_eq(e, 92), 92, Bool.pick(U32, U32.is_eq(e, 47), 47,
156 Bool.pick(U32, U32.is_eq(e, 98), 8, Bool.pick(U32, U32.is_eq(e, 102), 12, Bool.pick(U32, U32.is_eq(e, 110), 10,
157 Bool.pick(U32, U32.is_eq(e, 114), 13, Bool.pick(U32, U32.is_eq(e, 116), 9, 99))))))))
158
159# Parse
160# -----
161# A state holds the offset of its next byte; the buffer goes beside it. A
162# string with no escape is copied out of the buffer when it closes; at its
163# first escape it moves into a writer.
164
165type Sb is Type:
166 BValue{i: U32, stack: List<&1, Open>}
167 BFirst{i: U32, open: Open, stack: List<&1, Open>}
168 BKey{i: U32, stack: List<&1, Open>}
169 BColon{key: Bytes.Bytes, i: U32, stack: List<&1, Open>}
170 BStr{i: U32, start: U32, key: Bool, stack: List<&1, Open>}
171 BEsc{i: U32, acc: W, key: Bool, stack: List<&1, Open>}
172 BNum{i: U32, start: U32, st: U32, stack: List<&1, Open>}
173 BAfter{v: Val, i: U32, stack: List<&1, Open>}
174 BSep{i: U32, open: Open, stack: List<&1, Open>}
175 BEnd{v: Val, i: U32}
176 BOk{v: Val}
177 BFail{}
178
179type Cp is Data:
180 Cp{c: U32, w: U32}
181
182def pk.if(ok: Bool, a: Array<U32>, +i: U32) -> Array<U32> & U32:
183 match ok:
184 case True{}:
185 Bytes.peek(a, i)
186 case False{}:
187 (a, 256)
188
189# Byte i, or 256 at the end, which no rule accepts.
190def pk(a: Array<U32>, +len: U32, +i: U32) -> Array<U32> & U32:
191 pk.if(U32.is_lt(i, len), a, i)
192
193def is_ws(+c: U32) -> Bool:
194 U32.is_eq(c, 32) || U32.is_eq(c, 9) || U32.is_eq(c, 10) || U32.is_eq(c, 13)
195
196# A string byte that needs no check: ASCII, not a control, quote or backslash.
197def plain(+c: U32) -> Bool:
198 U32.is_le(32, c) && U32.is_lt(c, 128) && U32.is_ne(c, 34) && U32.is_ne(c, 92)
199
200def pos.of(+i: U32, r: Array<U32> & U32) -> Array<U32> & U32 & U32:
201 (a, +c) = r
202 (a, i, c)
203
204# The offset i and its byte.
205def pos(a: Array<U32>, +len: U32, +i: U32) -> Array<U32> & U32 & U32:
206 pos.of(i, pk(a, len, i))
207
208def run.cls(~ok: @+c: U32 -> Bool, r: Array<U32> & U32) -> Array<U32> & U32 & Bool:
209 (a, +c) = r
210 (a, c, ok(c))
211
212# g bounds the loop; it is the parser's fuel, shared, so no count is built per run.
213def run.go(~ok: @+c: U32 -> Bool, g: Nat, r: Array<U32> & U32 & Bool, +len: U32, +i: U32) -> Array<U32> & U32 & U32:
214 match g:
215 case 0n:
216 (a, +c, more) = r
217 (a, i, c)
218 case 1n+h:
219 (a, +c, more) = r
220 match more:
221 case True{}:
222 run.go(~ok, h, run.cls(~ok, pk(a, len, (i + 1 : U32))), len, (i + 1 : U32))
223 case False{}:
224 (a, i, c)
225
226# The first offset from i whose byte is not ok, and that byte.
227def run(~ok: @+c: U32 -> Bool, +g: Nat, a: Array<U32>, +len: U32, +i: U32) -> Array<U32> & U32 & U32:
228 run.go(~ok, g, run.cls(~ok, pk(a, len, i)), len, i)
229
230def word.go(w: String, ok: Bool, r: Array<U32> & U32, +len: U32, +j: U32) -> Array<U32> & Bool:
231 match w:
232 case SNil{}:
233 (a, b) = r
234 (a, ok)
235 case SCon{Chr{+c}, t}:
236 (a, +b) = r
237 word.go(t, ok && U32.is_eq(b, c), pk(a, len, (j + 1 : U32)), len, (j + 1 : U32))
238
239# Do the bytes from j spell w?
240def word(a: Array<U32>, +len: U32, w: String, +j: U32) -> Array<U32> & Bool:
241 word.go(w, True{}, pk(a, len, j), len, j)
242
243def hex4.b.go(n: Nat, r: Array<U32> & U32, +len: U32, +j: U32, +acc: U32) -> Array<U32> & U32:
244 match n:
245 case 0n:
246 (a, b) = r
247 (a, acc)
248 case 1n+k:
249 (a, +b) = r
250 +h = hexd(b)
251 hex4.b.go(k, pk(a, len, (j + 1 : U32)), len, (j + 1 : U32), Bool.pick(U32, U32.is_eq(h, 99) || U32.is_eq(acc, 65536), 65536, (acc * 16 + h : U32)))
252
253# Four hex digits from byte j, or 65536 if one is not a hex digit.
254def hex4.b(a: Array<U32>, +len: U32, +j: U32) -> Array<U32> & U32:
255 hex4.b.go(4n, pk(a, len, j), len, j, 0)
256
257def cont(+b: U32) -> Bool:
258 U32.is_eq((b .&. 192 : U32), 128)
259
260# RFC 3629 §4: overlong forms, surrogates, and code points past U+10FFFF are invalid, width 0.
261def utf8.n(+b0: U32, +b1: U32, +b2: U32, +b3: U32) -> Cp:
262 +x1 = (b1 .&. 63 : U32)
263 +x2 = (b2 .&. 63 : U32)
264 +x3 = (b3 .&. 63 : U32)
265 +c2 = (((b0 .&. 31) << 6n) .|. x1 : U32)
266 +c3 = ((((b0 .&. 15) << 12n) .|. (x1 << 6n)) .|. x2 : U32)
267 +c4 = (((((b0 .&. 7) << 18n) .|. (x1 << 12n)) .|. (x2 << 6n)) .|. x3 : U32)
268 +ok2 = U32.is_le(192, b0) && U32.is_lt(b0, 224) && cont(b1) && U32.is_le(128, c2)
269 +ok3 = U32.is_le(224, b0) && U32.is_lt(b0, 240) && cont(b1) && cont(b2) && U32.is_le(2048, c3) && (U32.is_lt(c3, 55296) || U32.is_lt(57343, c3))
270 +ok4 = U32.is_le(240, b0) && U32.is_lt(b0, 248) && cont(b1) && cont(b2) && cont(b3) && U32.is_le(65536, c4) && U32.is_le(c4, 1114111)
271 Bool.pick(Cp, ok2, Cp{c2, 2}, Bool.pick(Cp, ok3, Cp{c3, 3}, Bool.pick(Cp, ok4, Cp{c4, 4}, Cp{0, 0})))
272
273def utf8.b3(+b0: U32, +b1: U32, +b2: U32, r: Array<U32> & U32) -> Array<U32> & Cp:
274 (a, +b3) = r
275 (a, utf8.n(b0, b1, b2, b3))
276
277def utf8.b2(+len: U32, +i: U32, +b0: U32, +b1: U32, r: Array<U32> & U32) -> Array<U32> & Cp:
278 (a, +b2) = r
279 utf8.b3(b0, b1, b2, pk(a, len, (i + 3 : U32)))
280
281def utf8.b1(+len: U32, +i: U32, +b0: U32, r: Array<U32> & U32) -> Array<U32> & Cp:
282 (a, +b1) = r
283 utf8.b2(len, i, b0, b1, pk(a, len, (i + 2 : U32)))
284
285# The code point whose lead byte b0 is at i.
286def utf8.at(a: Array<U32>, +len: U32, +i: U32, +b0: U32) -> Array<U32> & Cp:
287 utf8.b1(len, i, b0, pk(a, len, (i + 1 : U32)))
288
289def slice.of(+n: U32, r: Array<U32> & Array<U32>) -> Array<U32> & Bytes.Bytes:
290 (a, out) = r
291 (a, Bytes.Bytes{n, out})
292
293# The n bytes from start, copied.
294def slice(+n: U32, +start: U32, a: Array<U32>) -> Array<U32> & Bytes.Bytes:
295 slice.of(n, Bytes.copy(n, a, Bytes.alloc(n), start, 0))
296
297def str.b.done(key: Bool, s: Bytes.Bytes, +i: U32, stack: List<&1, Open>) -> Sb:
298 match key:
299 case True{}:
300 BColon{s, i, stack}
301 case False{}:
302 BAfter{Str{s}, i, stack}
303
304def esc.b.lo.if(ok: Bool, +i: U32, +hi: U32, +lo: U32, acc: W, key: Bool, stack: List<&1, Open>) -> Sb:
305 match ok:
306 case True{}:
307 BEsc{(i + 12 : U32), w.cp((65536 + (hi - 55296 : U32) * 1024 + (lo - 56320 : U32) : U32), acc), key, stack}
308 case False{}:
309 BEsc{(i + 6 : U32), w.cp(65533, acc), key, stack}
310
311def esc.b.lo(+i: U32, +hi: U32, acc: W, key: Bool, stack: List<&1, Open>, r: Array<U32> & U32) -> Array<U32> & Sb:
312 (a, +lo) = r
313 (a, esc.b.lo.if(is_lo(lo), i, hi, lo, acc, key, stack))
314
315# §8.2: a high surrogate pairs with a following \uDC00-\uDFFF; a lone one is U+FFFD.
316def esc.b.pair(+len: U32, +i: U32, +hi: U32, acc: W, key: Bool, stack: List<&1, Open>, r: Array<U32> & Bool) -> Array<U32> & Sb:
317 (a, ok) = r
318 match ok:
319 case True{}:
320 esc.b.lo(i, hi, acc, key, stack, hex4.b(a, len, (i + 8 : U32)))
321 case False{}:
322 (a, BEsc{(i + 6 : U32), w.cp(65533, acc), key, stack})
323
324# 0: not four hex digits; 1: high surrogate; 2: low surrogate; 3: other.
325def u.class(+v: U32) -> U32:
326 Bool.pick(U32, U32.is_eq(v, 65536), 0, Bool.pick(U32, is_hi(v), 1, Bool.pick(U32, is_lo(v), 2, 3)))
327
328def esc.b.u.of(+k: U32, a: Array<U32>, +len: U32, +i: U32, +v: U32, acc: W, key: Bool, stack: List<&1, Open>) -> Array<U32> & Sb:
329 match k:
330 case 0:
331 (a, BFail{})
332 case 1:
333 esc.b.pair(len, i, v, acc, key, stack, word(a, len, "\\u", (i + 6 : U32)))
334 case 2:
335 (a, BEsc{(i + 6 : U32), w.cp(65533, acc), key, stack})
336 case _:
337 (a, BEsc{(i + 6 : U32), w.cp(v, acc), key, stack})
338
339def esc.b.u(+len: U32, +i: U32, acc: W, key: Bool, stack: List<&1, Open>, r: Array<U32> & U32) -> Array<U32> & Sb:
340 (a, +v) = r
341 esc.b.u.of(u.class(v), a, len, i, v, acc, key, stack)
342
343# The escape whose backslash is at i.
344def esc.b.one(+len: U32, +i: U32, acc: W, key: Bool, stack: List<&1, Open>, r: Array<U32> & U32) -> Array<U32> & Sb:
345 (a, +e) = r
346 match e:
347 case 117:
348 esc.b.u(len, i, acc, key, stack, hex4.b(a, len, (i + 2 : U32)))
349 case _:
350 +v = esc.simple(e)
351 (a, Bool.pick(Sb, U32.is_eq(v, 99), BFail{}, BEsc{(i + 2 : U32), w.put(acc, v), key, stack}))
352
353def esc.b.cp(acc: W, key: Bool, stack: List<&1, Open>, +i: U32, r: Array<U32> & Cp) -> Array<U32> & Sb:
354 (a, Cp{+c, +n}) = r
355 (a, Bool.pick(Sb, U32.is_eq(n, 0), BFail{}, BEsc{(i + n : U32), w.cp(c, acc), key, stack}))
356
357# §7: unescaped chars below U+0020 are not allowed in a string.
358def esc.b.other(ascii: Bool, +c: U32, a: Array<U32>, +len: U32, +i: U32, acc: W, key: Bool, stack: List<&1, Open>) -> Array<U32> & Sb:
359 match ascii:
360 case True{}:
361 (a, Bool.pick(Sb, U32.is_lt(c, 32), BFail{}, BEsc{(i + 1 : U32), w.put(acc, c), key, stack}))
362 case False{}:
363 esc.b.cp(acc, key, stack, i, utf8.at(a, len, i, c))
364
365# A string after its first escape.
366def esc.b(r: Array<U32> & U32, +len: U32, +i: U32, acc: W, key: Bool, stack: List<&1, Open>) -> Array<U32> & Sb:
367 (a, +c) = r
368 match c:
369 case 34:
370 (a, str.b.done(key, w.done(acc), (i + 1 : U32), stack))
371 case 92:
372 esc.b.one(len, i, acc, key, stack, pk(a, len, (i + 1 : U32)))
373 case 256:
374 (a, BFail{})
375 case _:
376 esc.b.other(U32.is_lt(c, 128), c, a, len, i, acc, key, stack)
377
378def str.b.close(key: Bool, +i: U32, stack: List<&1, Open>, r: Array<U32> & Bytes.Bytes) -> Array<U32> & Sb:
379 (a, s) = r
380 (a, str.b.done(key, s, (i + 1 : U32), stack))
381
382def str.b.esc(+len: U32, +i: U32, key: Bool, stack: List<&1, Open>, r: Array<U32> & Bytes.Bytes) -> Array<U32> & Sb:
383 (a, s) = r
384 esc.b.one(len, i, w.of(s), key, stack, pk(a, len, (i + 1 : U32)))
385
386def str.b.cp(+start: U32, key: Bool, stack: List<&1, Open>, +i: U32, r: Array<U32> & Cp) -> Array<U32> & Sb:
387 (a, Cp{+c, +n}) = r
388 (a, Bool.pick(Sb, U32.is_eq(n, 0), BFail{}, BStr{(i + n : U32), start, key, stack}))
389
390def str.b.other(ascii: Bool, +c: U32, a: Array<U32>, +len: U32, +i: U32, +start: U32, key: Bool, stack: List<&1, Open>) -> Array<U32> & Sb:
391 match ascii:
392 case True{}:
393 (a, Bool.pick(Sb, U32.is_lt(c, 32), BFail{}, BStr{(i + 1 : U32), start, key, stack}))
394 case False{}:
395 str.b.cp(start, key, stack, i, utf8.at(a, len, i, c))
396
397# A string whose text so far starts at start and has no escape.
398def str.b(r: Array<U32> & U32, +len: U32, +i: U32, +start: U32, key: Bool, stack: List<&1, Open>) -> Array<U32> & Sb:
399 (a, +c) = r
400 match c:
401 case 34:
402 str.b.close(key, i, stack, slice((i - start : U32), start, a))
403 case 92:
404 str.b.esc(len, i, key, stack, slice((i - start : U32), start, a))
405 case 256:
406 (a, BFail{})
407 case _:
408 str.b.other(U32.is_lt(c, 128), c, a, len, i, start, key, stack)
409
410def num.b.fin(+i: U32, stack: List<&1, Open>, r: Array<U32> & Bytes.Bytes) -> Array<U32> & Sb:
411 (a, s) = r
412 (a, BAfter{Num{s}, i, stack})
413
414def num.b.stop(ok: Bool, a: Array<U32>, +i: U32, +start: U32, stack: List<&1, Open>) -> Array<U32> & Sb:
415 match ok:
416 case True{}:
417 num.b.fin(i, stack, slice((i - start : U32), start, a))
418 case False{}:
419 (a, BFail{})
420
421def num.b.if(stop: Bool, a: Array<U32>, +i: U32, +start: U32, +st: U32, +n: U32, stack: List<&1, Open>) -> Array<U32> & Sb:
422 match stop:
423 case True{}:
424 num.b.stop(num.accepts(st), a, i, start, stack)
425 case False{}:
426 (a, BNum{(i + 1 : U32), start, n, stack})
427
428def num.b(r: Array<U32> & U32, +i: U32, +start: U32, +st: U32, stack: List<&1, Open>) -> Array<U32> & Sb:
429 (a, +c) = r
430 +n = num.trans(st, c)
431 num.b.if(U32.is_eq(n, 99), a, i, start, st, n, stack)
432
433def lit.b(+i: U32, +n: U32, v: Val, stack: List<&1, Open>, r: Array<U32> & Bool) -> Array<U32> & Sb:
434 (a, ok) = r
435 match ok:
436 case True{}:
437 (a, BAfter{v, (i + n : U32), stack})
438 case False{}:
439 (a, BFail{})
440
441def value.b(r: Array<U32> & U32, +len: U32, +i: U32, stack: List<&1, Open>) -> Array<U32> & Sb:
442 (a, +c) = r
443 match c:
444 case 32:
445 (a, BValue{(i + 1 : U32), stack})
446 case 9:
447 (a, BValue{(i + 1 : U32), stack})
448 case 10:
449 (a, BValue{(i + 1 : U32), stack})
450 case 13:
451 (a, BValue{(i + 1 : U32), stack})
452 case 91:
453 (a, BFirst{(i + 1 : U32), OArr{Nil{}}, stack})
454 case 123:
455 (a, BFirst{(i + 1 : U32), OObj{Nil{}}, stack})
456 case 34:
457 (a, BStr{(i + 1 : U32), (i + 1 : U32), False{}, stack})
458 case 116:
459 lit.b(i, 4, Flag{True{}}, stack, word(a, len, "true", i))
460 case 102:
461 lit.b(i, 5, Flag{False{}}, stack, word(a, len, "false", i))
462 case 110:
463 lit.b(i, 4, Null{}, stack, word(a, len, "null", i))
464 case _:
465 (a, BNum{i, i, 0, stack})
466
467# After "[" or "{": the closing bracket, or the first item.
468def first.b.end(open: Open, +c: U32, +i: U32, stack: List<&1, Open>) -> Sb:
469 match open:
470 case OArr{xs}:
471 Bool.pick(Sb, U32.is_eq(c, 93), BAfter{Arr{xs}, (i + 1 : U32), stack}, BFail{})
472 case OObj{kvs}:
473 Bool.pick(Sb, U32.is_eq(c, 125), BAfter{Obj{kvs}, (i + 1 : U32), stack}, BFail{})
474 case OKey{kvs, k}:
475 BFail{}
476
477def first.b.open(open: Open, +i: U32, stack: List<&1, Open>) -> Sb:
478 match open:
479 case OArr{xs}:
480 BValue{i, Con{OArr{xs}, stack}}
481 case OObj{kvs}:
482 BKey{i, Con{OObj{kvs}, stack}}
483 case OKey{kvs, k}:
484 BFail{}
485
486def first.b(r: Array<U32> & U32, +i: U32, open: Open, stack: List<&1, Open>) -> Array<U32> & Sb:
487 (a, +c) = r
488 match c:
489 case 32:
490 (a, BFirst{(i + 1 : U32), open, stack})
491 case 9:
492 (a, BFirst{(i + 1 : U32), open, stack})
493 case 10:
494 (a, BFirst{(i + 1 : U32), open, stack})
495 case 13:
496 (a, BFirst{(i + 1 : U32), open, stack})
497 case 93:
498 (a, first.b.end(open, c, i, stack))
499 case 125:
500 (a, first.b.end(open, c, i, stack))
501 case _:
502 (a, first.b.open(open, i, stack))
503
504def key.b(r: Array<U32> & U32, +i: U32, stack: List<&1, Open>) -> Array<U32> & Sb:
505 (a, +c) = r
506 match c:
507 case 32:
508 (a, BKey{(i + 1 : U32), stack})
509 case 9:
510 (a, BKey{(i + 1 : U32), stack})
511 case 10:
512 (a, BKey{(i + 1 : U32), stack})
513 case 13:
514 (a, BKey{(i + 1 : U32), stack})
515 case 34:
516 (a, BStr{(i + 1 : U32), (i + 1 : U32), True{}, stack})
517 case _:
518 (a, BFail{})
519
520def colon.b.top(k: Bytes.Bytes, +i: U32, stack: List<&1, Open>) -> Sb:
521 match stack:
522 case Nil{}:
523 BFail{}
524 case Con{OArr{xs}, up}:
525 BFail{}
526 case Con{OObj{kvs}, up}:
527 BValue{i, Con{OKey{kvs, k}, up}}
528 case Con{OKey{kvs, old}, up}:
529 BFail{}
530
531def colon.b(r: Array<U32> & U32, k: Bytes.Bytes, +i: U32, stack: List<&1, Open>) -> Array<U32> & Sb:
532 (a, +c) = r
533 match c:
534 case 32:
535 (a, BColon{k, (i + 1 : U32), stack})
536 case 9:
537 (a, BColon{k, (i + 1 : U32), stack})
538 case 10:
539 (a, BColon{k, (i + 1 : U32), stack})
540 case 13:
541 (a, BColon{k, (i + 1 : U32), stack})
542 case 58:
543 (a, colon.b.top(k, (i + 1 : U32), stack))
544 case _:
545 (a, BFail{})
546
547# A finished value joins its container.
548def after.b(v: Val, +i: U32, stack: List<&1, Open>) -> Sb:
549 match stack:
550 case Nil{}:
551 BEnd{v, i}
552 case Con{OArr{xs}, up}:
553 BSep{i, OArr{Con{v, xs}}, up}
554 case Con{OObj{kvs}, up}:
555 BFail{}
556 case Con{OKey{kvs, k}, up}:
557 BSep{i, OObj{Con{(k, v), kvs}}, up}
558
559def sep.b.comma(open: Open, +i: U32, up: List<&1, Open>) -> Sb:
560 match open:
561 case OArr{xs}:
562 BValue{i, Con{OArr{xs}, up}}
563 case OObj{kvs}:
564 BKey{i, Con{OObj{kvs}, up}}
565 case OKey{kvs, k}:
566 BFail{}
567
568def sep.b.close(open: Open, +c: U32, +i: U32, up: List<&1, Open>) -> Sb:
569 match open:
570 case OArr{xs}:
571 Bool.pick(Sb, U32.is_eq(c, 93), BAfter{Arr{List.reverse(&1, Val, xs)}, i, up}, BFail{})
572 case OObj{kvs}:
573 Bool.pick(Sb, U32.is_eq(c, 125), BAfter{Obj{List.reverse(&1, Bytes.Bytes & Val, kvs)}, i, up}, BFail{})
574 case OKey{kvs, k}:
575 BFail{}
576
577# After an item: "," or the closing bracket.
578def sep.b(r: Array<U32> & U32, +i: U32, open: Open, up: List<&1, Open>) -> Array<U32> & Sb:
579 (a, +c) = r
580 match c:
581 case 32:
582 (a, BSep{(i + 1 : U32), open, up})
583 case 9:
584 (a, BSep{(i + 1 : U32), open, up})
585 case 10:
586 (a, BSep{(i + 1 : U32), open, up})
587 case 13:
588 (a, BSep{(i + 1 : U32), open, up})
589 case 44:
590 (a, sep.b.comma(open, (i + 1 : U32), up))
591 case _:
592 (a, sep.b.close(open, c, (i + 1 : U32), up))
593
594def end.b(r: Array<U32> & U32, v: Val, +i: U32) -> Array<U32> & Sb:
595 (a, +c) = r
596 match c:
597 case 32:
598 (a, BEnd{v, (i + 1 : U32)})
599 case 9:
600 (a, BEnd{v, (i + 1 : U32)})
601 case 10:
602 (a, BEnd{v, (i + 1 : U32)})
603 case 13:
604 (a, BEnd{v, (i + 1 : U32)})
605 case 256:
606 (a, BOk{v})
607 case _:
608 (a, BFail{})
609
610# A run's end (a, i, c) to each step. The parts bind without + (bendlang/bend#1077).
611def value.r(+len: U32, stack: List<&1, Open>, r: Array<U32> & U32 & U32) -> Array<U32> & Sb:
612 (a, i, c) = r
613 value.b((a, c), len, i, stack)
614
615def first.r(open: Open, stack: List<&1, Open>, r: Array<U32> & U32 & U32) -> Array<U32> & Sb:
616 (a, i, c) = r
617 first.b((a, c), i, open, stack)
618
619def key.r(stack: List<&1, Open>, r: Array<U32> & U32 & U32) -> Array<U32> & Sb:
620 (a, i, c) = r
621 key.b((a, c), i, stack)
622
623def colon.r(k: Bytes.Bytes, stack: List<&1, Open>, r: Array<U32> & U32 & U32) -> Array<U32> & Sb:
624 (a, i, c) = r
625 colon.b((a, c), k, i, stack)
626
627def str.r(+len: U32, +s: U32, key: Bool, stack: List<&1, Open>, r: Array<U32> & U32 & U32) -> Array<U32> & Sb:
628 (a, i, c) = r
629 str.b((a, c), len, i, s, key, stack)
630
631def num.r(+s: U32, +st: U32, stack: List<&1, Open>, r: Array<U32> & U32 & U32) -> Array<U32> & Sb:
632 (a, i, c) = r
633 num.b((a, c), i, s, st, stack)
634
635def sep.r(open: Open, up: List<&1, Open>, r: Array<U32> & U32 & U32) -> Array<U32> & Sb:
636 (a, i, c) = r
637 sep.b((a, c), i, open, up)
638
639def end.r(v: Val, r: Array<U32> & U32 & U32) -> Array<U32> & Sb:
640 (a, i, c) = r
641 end.b((a, c), v, i)
642
643def w.span.go(n: Nat, r: Array<U32> & U32, +i: U32, o: W) -> Array<U32> & W:
644 match n:
645 case 0n:
646 (a, v) = r
647 (a, o)
648 case 1n+k:
649 (a, +c) = r
650 w.span.go(k, Bytes.peek(a, (i + 1 : U32)), (i + 1 : U32), w.put(o, c))
651
652def esc.r.go(+len: U32, +j: U32, c: U32, key: Bool, stack: List<&1, Open>, r: Array<U32> & W) -> Array<U32> & Sb:
653 (a, acc) = r
654 esc.b((a, c), len, j, acc, key, stack)
655
656# The plain bytes from i to the run's end go onto acc in one loop.
657def esc.r(+len: U32, +i: U32, acc: W, key: Bool, stack: List<&1, Open>, r: Array<U32> & U32 & U32) -> Array<U32> & Sb:
658 (a, +j, c) = r
659 esc.r.go(len, j, c, key, stack, w.span.go(U32.to_nat((j - i : U32)), Bytes.peek(a, i), i, acc))
660
661# States 3, 5 and 8 take digits until the number's part ends.
662def num.run(loop: Bool, +g: Nat, a: Array<U32>, +len: U32, +i: U32) -> Array<U32> & U32 & U32:
663 match loop:
664 case True{}:
665 run(~digit, g, a, len, i)
666 case False{}:
667 pos(a, len, i)
668
669# fuel: a step eats a byte, or ends a number, a value, or an opening bracket, so 4 * len + 4 steps are enough.
670def runb(+fuel: Nat, r: Array<U32> & Sb, +len: U32) -> Maybe<&1, Val>:
671 match fuel:
672 case 0n:
673 None{}
674 case 1n+f:
675 (a, sb) = r
676 match sb:
677 case BOk{v}:
678 Some{v}
679 case BFail{}:
680 None{}
681 case BValue{+i, stack}:
682 runb(f, value.r(len, stack, run(~is_ws, f, a, len, i)), len)
683 case BFirst{+i, open, stack}:
684 runb(f, first.r(open, stack, run(~is_ws, f, a, len, i)), len)
685 case BKey{+i, stack}:
686 runb(f, key.r(stack, run(~is_ws, f, a, len, i)), len)
687 case BColon{k, +i, stack}:
688 runb(f, colon.r(k, stack, run(~is_ws, f, a, len, i)), len)
689 case BStr{+i, +s, k, stack}:
690 runb(f, str.r(len, s, k, stack, run(~plain, f, a, len, i)), len)
691 case BEsc{+i, acc, k, stack}:
692 runb(f, esc.r(len, i, acc, k, stack, run(~plain, f, a, len, i)), len)
693 case BNum{+i, +s, +st, stack}:
694 runb(f, num.r(s, st, stack, num.run(U32.is_eq(st, 3) || U32.is_eq(st, 5) || U32.is_eq(st, 8), f, a, len, i)), len)
695 case BAfter{v, +i, stack}:
696 runb(f, (a, after.b(v, i, stack)), len)
697 case BSep{+i, open, stack}:
698 runb(f, sep.r(open, stack, run(~is_ws, f, a, len, i)), len)
699 case BEnd{v, +i}:
700 runb(f, end.r(v, run(~is_ws, f, a, len, i)), len)
701
702# One JSON text in UTF-8. None for bad JSON or bad UTF-8 (RFC 8259 §8.1).
703def parse.bytes(b: Bytes.Bytes) -> Maybe<&1, Val>:
704 Bytes.Bytes{+len, buf} = b
705 runb(Nat.add(Nat.mul(U32.to_nat(len), 4n), 4n), (buf, BValue{0, Nil{}}), len)
706
707# Access
708# ------
709
710def get.pick(v: Val, found: Maybe<&1, Val>, r: Bytes.Bytes & Bytes.Bytes & Bool) -> Bytes.Bytes & Maybe<&1, Val>:
711 (k, key, same) = r
712 (key, Bool.pick(Maybe<&1, Val>, same, Some{v}, found))
713
714def get.step(k: Bytes.Bytes, v: Val, st: Bytes.Bytes & Maybe<&1, Val>) -> Bytes.Bytes & Maybe<&1, Val>:
715 (key, found) = st
716 get.pick(v, found, Bytes.eq(k, key))
717
718def get.go(kvs: List<&1, Bytes.Bytes & Val>, st: Bytes.Bytes & Maybe<&1, Val>) -> Maybe<&1, Val>:
719 match kvs:
720 case Nil{}:
721 (key, found) = st
722 found
723 case (k, v) <> t:
724 get.go(t, get.step(k, v, st))
725
726# §4: the value under key k of an object; the last one when k repeats, as most parsers do.
727def get(v: Val, k: String) -> Maybe<&1, Val>:
728 match v:
729 case Obj{kvs}:
730 get.go(kvs, (utf8(k), None{}))
731 case Null{}:
732 None{}
733 case Flag{on}:
734 None{}
735 case Num{n}:
736 None{}
737 case Str{s}:
738 None{}
739 case Arr{xs}:
740 None{}
741
742def at.go(xs: List<&1, Val>, n: Nat) -> Maybe<&1, Val>:
743 match xs:
744 case Nil{}:
745 None{}
746 case Con{v, t}:
747 match n:
748 case 0n:
749 Some{v}
750 case 1n+p:
751 at.go(t, p)
752
753# Item n of an array.
754def at(v: Val, n: Nat) -> Maybe<&1, Val>:
755 match v:
756 case Arr{xs}:
757 at.go(xs, n)
758 case Null{}:
759 None{}
760 case Flag{on}:
761 None{}
762 case Num{s}:
763 None{}
764 case Str{s}:
765 None{}
766 case Obj{kvs}:
767 None{}
768
769def u32.over(+acc: U32, +c: U32) -> Bool:
770 Bool.or(U32.is_lt(429496729, acc), Bool.and(U32.is_eq(acc, 429496729), U32.is_lt(53, c)))
771
772def u32.dig(s: String, +acc: U32, bad: Bool) -> Maybe<&2, U32>:
773 match s:
774 case SNil{}:
775 match bad:
776 case True{}:
777 None{}
778 case False{}:
779 Some{acc}
780 case SCon{Chr{+c}, t}:
781 u32.dig(t, (acc * 10 + (c - 48 : U32) : U32), Bool.or(bad, Bool.or(Bool.not(digit(c)), u32.over(acc, c))))
782
783def u32.zero(t: String) -> Maybe<&2, U32>:
784 match t:
785 case SNil{}:
786 Some{0}
787 case SCon{d, u}:
788 None{}
789
790def u32.lead(+c: U32, t: String, zero: Bool) -> Maybe<&2, U32>:
791 match zero:
792 case True{}:
793 u32.zero(t)
794 case False{}:
795 u32.dig(t, (c - 48 : U32), Bool.or(Bool.not(digit(c)), u32.over(0, c)))
796
797def u32.num(s: String) -> Maybe<&2, U32>:
798 match s:
799 case SNil{}:
800 None{}
801 case SCon{Chr{+c}, t}:
802 u32.lead(c, t, U32.is_eq(c, 48))
803
804# A number that is a whole U32, with no sign, fraction or exponent.
805def u32(v: Val) -> Maybe<&2, U32>:
806 match v:
807 case Num{s}:
808 u32.num(Bytes.to_string(s))
809 case Null{}:
810 None{}
811 case Flag{on}:
812 None{}
813 case Str{s}:
814 None{}
815 case Arr{xs}:
816 None{}
817 case Obj{kvs}:
818 None{}
819
820# Encode
821# ------
822
823def w.ctl(ctl: Bool, +c: U32, o: W) -> W:
824 match ctl:
825 case True{}:
826 w.put(w.put(w.put(w.put(w.put(w.put(o, 92), 117), 48), 48), w.hex(U32.shrn(c, 4n))), w.hex((c .&. 15 : U32)))
827 case False{}:
828 w.put(o, c)
829
830# §7: quote, backslash and control chars are escaped. Other bytes are already UTF-8.
831def w.esc.c(+c: U32, o: W) -> W:
832 match c:
833 case 34:
834 w.put(w.put(o, 92), 34)
835 case 92:
836 w.put(w.put(o, 92), 92)
837 case 10:
838 w.put(w.put(o, 92), 110)
839 case 13:
840 w.put(w.put(o, 92), 114)
841 case 9:
842 w.put(w.put(o, 92), 116)
843 case _:
844 w.ctl(U32.is_lt(c, 32), c, o)
845
846def w.bytes.go(n: Nat, r: Array<U32> & U32, +i: U32, o: W) -> W:
847 match n:
848 case 0n:
849 o
850 case 1n+k:
851 (a, +c) = r
852 w.bytes.go(k, Bytes.peek(a, (i + 1 : U32)), (i + 1 : U32), w.put(o, c))
853
854def w.bytes(b: Bytes.Bytes, o: W) -> W:
855 Bytes.Bytes{+len, buf} = b
856 w.bytes.go(U32.to_nat(len), Bytes.peek(buf, 0), 0, o)
857
858def w.str.go(n: Nat, r: Array<U32> & U32, +i: U32, o: W) -> W:
859 match n:
860 case 0n:
861 w.put(o, 34)
862 case 1n+k:
863 (a, +c) = r
864 w.str.go(k, Bytes.peek(a, (i + 1 : U32)), (i + 1 : U32), w.esc.c(c, o))
865
866# A quoted, escaped string.
867def w.str(b: Bytes.Bytes, o: W) -> W:
868 Bytes.Bytes{+len, buf} = b
869 w.str.go(U32.to_nat(len), Bytes.peek(buf, 0), 0, w.put(o, 34))
870
871type Item is Type:
872 ILit{s: String}
873 IKey{k: Bytes.Bytes}
874 IVal{v: Val}
875
876def items.sep(first: Bool, tail: List<&1, Item>) -> List<&1, Item>:
877 match first:
878 case True{}:
879 tail
880 case False{}:
881 Con{ILit{","}, tail}
882
883def items.arr(xs: List<&1, Val>, first: Bool, rest: List<&1, Item>) -> List<&1, Item>:
884 match xs:
885 case Nil{}:
886 Con{ILit{"]"}, rest}
887 case Con{x, t}:
888 items.sep(first, Con{IVal{x}, items.arr(t, False{}, rest)})
889
890def items.obj(kvs: List<&1, Bytes.Bytes & Val>, first: Bool, rest: List<&1, Item>) -> List<&1, Item>:
891 match kvs:
892 case Nil{}:
893 Con{ILit{"}"}, rest}
894 case (k, v) <> t:
895 items.sep(first, Con{IKey{k}, Con{IVal{v}, items.obj(t, False{}, rest)}})
896
897# ponytail: @unsafe because it walks a work list, not the Val; each step
898# emits text or swaps a container for its strictly smaller parts.
899@unsafe
900def encb.go(items: List<&1, Item>, o: W) -> W:
901 match items:
902 case Nil{}:
903 o
904 case Con{ILit{s}, t}:
905 encb.go(t, w.text(s, o))
906 case Con{IKey{k}, t}:
907 encb.go(t, w.put(w.str(k, o), 58))
908 case Con{IVal{Null{}}, t}:
909 encb.go(t, w.text("null", o))
910 case Con{IVal{Flag{True{}}}, t}:
911 encb.go(t, w.text("true", o))
912 case Con{IVal{Flag{False{}}}, t}:
913 encb.go(t, w.text("false", o))
914 case Con{IVal{Num{n}}, t}:
915 encb.go(t, w.bytes(n, o))
916 case Con{IVal{Str{s}}, t}:
917 encb.go(t, w.str(s, o))
918 case Con{IVal{Arr{xs}}, t}:
919 encb.go(Con{ILit{"["}, items.arr(xs, True{}, t)}, o)
920 case Con{IVal{Obj{kvs}}, t}:
921 encb.go(Con{ILit{"{"}, items.obj(kvs, True{}, t)}, o)
922
923# Compact JSON in UTF-8, with object fields in their order.
924def encode.bytes(v: Val) -> Bytes.Bytes:
925 w.done(encb.go(Con{IVal{v}, Nil{}}, W{Bytes.alloc(64), 16, 0, 0}))