aboutsummaryrefslogtreecommitdiff
path: root/src/boot/utility.boot
blob: ec51df12264cc116c10f422a8771ede3cb935b72 (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
-- Copyright (C) 2012, Gabriel Dos Reis.
-- All rights reserved.
--
-- Redistribution and use in source and binary forms, with or without
-- modification, are permitted provided that the following conditions are
-- met:
--
--     - Redistributions of source code must retain the above copyright
--       notice, this list of conditions and the following disclaimer.
--
--     - Redistributions in binary form must reproduce the above copyright
--       notice, this list of conditions and the following disclaimer in
--       the documentation and/or other materials provided with the
--       distribution.
--
--     - Neither the name of The Numerical Algorithms Group Ltd. nor the
--       names of its contributors may be used to endorse or promote products
--       derived from this software without specific prior written permission.
--
-- THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
-- IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
-- TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
-- PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
-- OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
-- EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
-- PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
-- PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
-- LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
-- NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
-- SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
--

--%
--% Definitions in this file provide runtime support for the Boot
--% language.  As such, some of the definitions (e.g. reverse, append, etc)
--% use `unusual' style.  These functions are used in code generated
--% by the Boot translator.  Others are handy library functions.
--%

namespace BOOTTRAN ==
  import namespace System
  import namespace AxiomCore

namespace BOOTTRAN

module utility (objectMember?, symbolMember?, stringMember?,
  charMember?, scalarMember?, listMember?, reverse, reverse!,
  lastNode, append, append!, copyList, substitute, substitute!,
  setDifference, setUnion, setIntersection,
  symbolAssoc, applySubst, applySubst!, applySubstNQ, objectAssoc,
  remove, removeSymbol, atomic?, every?, any?, take, takeWhile, drop,
  copyTree, finishLine, stringPrefix?, stringSuffix?,
  findChar, charPosition) where
    substitute: (%Thing,%Thing,%Thing) -> %Thing
    substitute!: (%Thing,%Thing,%Thing) -> %Thing
    append: (%List %Thing,%List %Thing) -> %List %Thing
    append!: (%List %Thing,%List %Thing) -> %List %Thing
    copyList: %List %Thing -> %List %Thing
    lastNode: %List %Thing -> %Maybe %Node %Thing
    removeSymbol: (%List %Thing, %Symbol) -> %List %Thing
    remove: (%List %Thing, %Thing) -> %List %Thing
    objectAssoc: (%Thing, %List %Thing) -> %Maybe %Pair(%Thing,%Thing)
    symbolAssoc: (%Symbol,%List %Thing) -> %Maybe %Pair(%Symbol,%Thing)
    setDifference: (%List %Thing,%List %Thing) -> %List %Thing
    setUnion: (%List %Thing,%List %Thing) -> %List %Thing
    setIntersection: (%List %Thing,%List %Thing) -> %List %Thing
    atomic?: %Thing -> %Boolean
    every?: (%Thing -> %Thing, %List %Thing) -> %Thing
    any?: (%Thing -> %Thing, %List %Thing) -> %Thing
    take: (%Short,%List %Thing) -> %List %Thing
    takeWhile: (%Thing -> %Thing, %List %Thing) -> %List %Thing
    drop: (%Short,%List %Thing) -> %List %Thing
    copyTree: %Thing -> %Thing
    finishLine: %Thing -> %Void
    --FIXME: Next signature commented out because of GCL bugs
    -- firstNonblankPosition: (%String,%Short) -> %Maybe %Short
    firstBlankPosition: (%String,%Short) -> %Maybe %Short
    stringSuffix?: (%String,%String) -> %Maybe %Short
    stringPrefix?: (%String,%String) -> %Maybe %Short

%defaultReadAndLoadSettings()

--%

++ Return true if `x' is an atom of a quotation.
atomic? x ==
  x isnt [.,:.] or x.op is 'QUOTE

++ Return the last image of `f' if all images of elements in `l'
++ are non-nil.  Otherwise return nil.
every?(f,l) ==
  and/[apply(f,x,nil) for x in l]

++ Return the first non-nil image of `f' of elements in `l'.
any?(f,l) ==
  or/[apply(f,x,nil) for x in l]

++ Return the `n' node prefixes of the list `l'.  If `n' is negative,
++ take from the end of the list.
take(n,l) ==
  n >= 0 => [x for x in l for . in 1..n]
  drop(#l+n,l)

++ Return the sublist of `l' whose elements have non-nil image by `f'.
takeWhile(f,l) ==
  [x for x in l while apply(f,x,nil)]

++ Return the `n+1'th node and its successors of the list `l'.
++ If `n' is negative, drop from the end.
drop(n,l) ==
  n >= 0 =>
    for . in 1..n while l is [.,:l] repeat nil
    l@%List(%Thing)
  take(#l+n,l)

copyTree t ==
  t is [.,:.] => [copyTree first t,:copyTree rest t]
  t

--% membership operators

objectMember?(x,l) ==
  repeat
    l = nil => return false
    l is [.,:.] =>
      sameObject?(x,first l) => return true
      l := rest l
    return sameObject?(x,l)

symbolMember?(s,l) ==
  repeat
    l = nil => return false
    l is [.,:.] =>
      symbolEq?(s,first l) => return true
      l := rest l
    return symbolEq?(s,l)

stringMember?(s,l) ==
  repeat
    l = nil => return false
    l is [.,:.] =>
      stringEq?(s,first l) => return true
      l := rest l
    return stringEq?(s,l)

charMember?(c,l) ==
  repeat
    l = nil => return false
    l is [.,:.] =>
      charEq?(c,first l) => return true
      l := rest l
    return charEq?(c,l)

scalarMember?(s,l) ==
  repeat
    l = nil => return false
    l is [.,:.] =>
      scalarEq?(s,first l) => return true
      l := rest l
    return scalarEq?(s,l)

listMember?(x,l) ==
  repeat
    l = nil => return false
    l is [.,:.] =>
      listEq?(x,first l) => return true
      l := rest l
    return listEq?(x,l)

--% list reversal

reverse l ==
  r := nil
  repeat
    l is [.,:.] =>
      r := [first l,:r]
      l := rest l
    return r

reverse! l ==
  l1 := nil
  repeat
    l is [.,:.] =>
      l2 := rest l
      l.rest := l1
      l1 := l
      l := l2
    return l1
    
--% return a pointer to the last cons-cell in the list `l'.

lastNode l ==
  while l is [.,:l'] and l' is [.,:.] repeat
    l := l'
  l

--% list copying
copyList l ==
  l isnt [.,:.] => l
  l' := t := [first l]
  repeat
    l := rest l
    l is [.,:.] =>
      t.rest := [first l]
      t := rest t
    t.rest := l
    return l'

--% append

append!(x,y) ==
  x = nil => y
  y = nil => x
  lastNode(x).rest := y
  x

append(x,y) ==
  append!(copyList x,y)

--% a-list

symbolAssoc(s,l) ==
  repeat
    l isnt [x,:l] => return nil
    x is [.,:.] and symbolEq?(s,first x) => return x

objectAssoc(x,l) ==
  repeat
    l isnt [p,:l] => return nil
    p is [.,:.] and sameObject?(first p,x) => return p

--% substitution

substitute!(y,x,s) ==
  s = nil => nil
  sameObject?(x,s) => y
  if s is [.,:.] then
    s.first := substitute!(y,x,first s)
    s.rest := substitute!(y,x,rest s)
  s

substitute(y,x,s) ==
  s = nil => nil
  sameObject?(x,s) => y
  s is [.,:.] =>
    h := substitute(y,x,first s)
    t := substitute(y,x,rest s)
    sameObject?(h,first s) and sameObject?(t,rest s) => s
    [h,:t]
  s
  
applySubst(sl,t) ==
  sl = nil => t
  t is [.,:.] =>
    hd := applySubst(sl,first t)
    tl := applySubst(sl,rest t)
    sameObject?(hd,first t) and sameObject?(tl,rest t) => t
    [hd,:tl]
  symbol? t and (p := symbolAssoc(t,sl)) => rest p
  t

applySubst!(sl,t) ==
  sl = nil => t
  t is [.,:.] =>
    hd := applySubst!(sl,first t)
    tl := applySubst!(sl,rest t)
    t.first := hd
    t.rest := tl
  symbol? t and (p := symbolAssoc(t,sl)) => rest p
  t

++ Like applySubst, but skip quoted materials.
applySubstNQ(sl,t) ==
  sl = nil => t
  t is [hd,:tl] =>
    hd is 'QUOTE => t
    hd := applySubstNQ(sl,hd)
    tl := applySubstNQ(sl,tl)
    sameObject?(hd,first t) and sameObject?(tl,rest t) => t
    [hd,:tl]
  symbol? t and (p := symbolAssoc(t,sl)) => rest p
  t

--% set operations

setDifference(x,y) ==
  x = nil => nil
  y = nil => x
  l := p := [nil]
  for [a,:.] in tails x | not objectMember?(a,y) repeat
    p.rest := [a]
    p := rest p
  rest l

++ Return the union of two lists of objects, with no duplicates.  
setUnion(x,y) ==
  z := nil
  for a in x | not objectMember?(a,z) repeat
    z := [a,:z]
  for a in y | not objectMember?(a,z) repeat
    z := [a,:z]
  reverse! z

++ Return the intersection of two lists of objects, with no duplicates.  
setIntersection(x,y) ==
  [a for a in x | objectMember?(a,y)]

--% removal

removeSymbol(l,x) ==
  before := nil
  l' := l
  repeat
    l' isnt [.,:.] => return l
    [y,:l'] := l'
    symbolEq?(x,y) => return append!(reverse! before,l')
    before := [y,:before]

removeScalar(l,x) ==
  before := nil
  l' := l
  repeat
    l' isnt [.,:.] => return l
    [y,:l'] := l'
    scalarEq?(x,y) => return append!(reverse! before,l')
    before := [y,:before]

removeValue(l,x) ==
  before := nil
  l' := l
  repeat
    l' isnt [.,:.] => return l
    [y,:l'] := l'
    valueEq?(x,y) => return append!(reverse! before,l')
    before := [y,:before]

remove(l,x) ==
  symbol? x => removeSymbol(l,x)
  char? x or integer? x => removeScalar(l,x)
  removeValue(l,x)

--% search

++ Return the index of the first match of character `c' in string `s'
++ starting from `k', if any.  Otherwise return nil.
findChar(c,s,k == 0) ==
  or/[i for i in k..maxIndex s | stringChar(s,i) = c]

++ Return the index of the character `c' in the string `s', if present.
++ Otherwise return the one-past-the-end index of `s' or k, whichever
++ is greater.
charPosition(c,s,k) ==
  n := # s
  k < 0 => n
  repeat
    k >= n => return k
    stringChar(s,k) = c => return k
    k := k + 1

firstNonblankPosition(s,k) ==
  or/[i for i in k..#s - 1 | stringChar(s,i) ~= char " "]

firstBlankPosition(s,k) ==
  or/[i for i in k..#s - 1 | stringChar(s,i) = char " "]
    
++ If `suf' is a suffix of `str' return the index into `str' at which the
++ match occurs.  Otherwise return nil.
stringSuffix?(suf,str) ==
  n1 := #suf
  n2 := #str
  n1 > n2 => nil
  n := n2 - n1
  and/[stringChar(suf,i) = stringChar(str,j) for i in 0..n1-1 for j in n..] => n
  nil

++ If the string `s1' is a prefix of `s2', return its length which is
++ also the one-past-the-last index into of the last character in `s2';
++ otherise return nil.
stringPrefix?(s1,s2) ==
  n1 := #s1
  n1 > #s2 => nil
  and/[s1.i = s2.i for i in 0..(n1-1)] => n1
  nil

--% I/O

++ Add a newline character and flush the output stream.
finishLine out ==
  writeNewline out
  flushOutput out