summary refs log tree commit diff stats
path: root/compiler/pas2nim/pasparse.nim
blob: 1db582f4e603b2778b60d1a9950808ad11b79527 (plain) (blame)
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
3
#
#
#           The Nim Compiler
#        (c) Copyright 2020 Nim Contributors
#
#    See the file "copying.txt", included in this
#    distribution, for details about the copyright.
#

## This module allows querying the compiler about
## diverse configuration settings. See also `compileOption`.

# Note: Only add new enum values at the end to ensure binary compatibility with
# other Nim compiler versions!

type
  SingleValueSetting* {.pure.} = enum ## \
                      ## settings resulting in a single string value
    arguments,        ## experimental: the arguments passed after '-r'
    outFile,          ## experimental: the output file
    outDir,           ## the output directory
    nimcacheDir,      ## the location of the 'nimcache' directory
    projectName,      ## the project's name that is being compiled
    projectPath,      ## experimental: some path to the project that is being compiled
    projectFull,      ## the full path to the project that is being compiled
    command,          ## experimental: the command (e.g. 'c', 'cpp', 'doc') passed to
                      ## the Nim compiler
    commandLine,      ## experimental: the command line passed to Nim
    linkOptions,      ## additional options passed to the linker
    compileOptions,   ## additional options passed to the C/C++ compiler
    ccompilerPath     ## the path to the C/C++ compiler
    backend           ## the backend (eg: c|cpp|objc|js); both `nim doc --backend:js`
                      ## and `nim js` would imply backend=js
    libPath           ## the absolute path to the stdlib library, i.e. nim's `--lib`, since 1.5.1
    gc                ## gc selected

  MultipleValueSetting* {.pure.} = enum ## \
                      ## settings resulting in a seq of string values
    nimblePaths,      ## the nimble path(s)
    searchPaths,      ## the search path for modules
    lazyPaths,        ## experimental: even more paths
    commandArgs,      ## the arguments passed to the Nim compiler
    cincludes,        ## the #include paths passed to the C/C++ compiler
    clibs             ## libraries passed to the C/C++ compiler

proc querySetting*(setting: SingleValueSetting): string {.
  compileTime, noSideEffect.} =
  ## Can be used to get a string compile-time option.
  ##
  ## See also:
  ## * `compileOption <system.html#compileOption,string>`_ for `on|off` options
  ## * `compileOption <system.html#compileOption,string,string>`_ for enum options
  ##
  runnableExamples:
    const nimcache = querySetting(SingleValueSetting.nimcacheDir)

proc querySettingSeq*(setting: MultipleValueSetting): seq[string] {.
  compileTime, noSideEffect.} =
  ## Can be used to get a multi-string compile-time option.
  ##
  ## See also:
  ## * `compileOption <system.html#compileOption,string>`_ for `on|off` options
  ## * `compileOption <system.html#compileOption,string,string>`_ for enum options
  runnableExamples:
    const nimblePaths = querySettingSeq(MultipleValueSetting.nimblePaths)
778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 1299 1300 1301 1302 1303 1304 1305 1306 1307 1308 1309 1310 1311 1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 1355 1356 1357 1358 1359 1360 1361 1362 1363 1364 1365 1366 1367 1368 1369 1370 1371 1372 1373 1374 1375 1376 1377 1378 1379 1380 1381 1382 1383 1384 1385 1386 1387 1388 1389 1390 1391 1392 1393 1394 1395 1396 1397 1398 1399 1400 1401 1402 1403 1404 1405 1406 1407 1408 1409 1410 1411 1412 1413 1414 1415 1416 1417 1418 1419 1420 1421 1422 1423 1424 1425 1426 1427 1428 1429 1430 1431 1432 1433 1434 1435 1436 1437 1438 1439 1440 1441 1442 1443 1444 1445 1446 1447 1448 1449 1450 1451 1452 1453 1454 1455 1456 1457 1458 1459 1460 1461 1462 1463 1464 1465 1466 1467 1468 1469 1470 1471 1472 1473 1474 1475 1476 1477 1478 1479 1480 1481 1482 1483 1484 1485 1486 1487 1488 1489 1490 1491 1492 1493 1494 1495 1496 1497 1498 1499 1500 1501 1502 1503 1504 1505 1506 1507 1508 1509 1510
#
#
#      Pas2nim - Pascal to Nimrod source converter
#        (c) Copyright 2010 Andreas Rumpf
#
#    See the file "copying.txt", included in this
#    distribution, for details about the copyright.
#

# This module implements the parser of the Pascal variant Nimrod is written in.
# It transfers a Pascal module into a Nimrod AST. Then the renderer can be
# used to convert the AST to its text representation.

import 
  os, llstream, paslex, idents, strutils, ast, astalgo, msgs, options

type 
  TSection = enum 
    seImplementation, seInterface
  TContext = enum 
    conExpr, conStmt, conTypeDesc
  TParserFlag* = enum
    pfRefs,             ## use "ref" instead of "ptr" for Pascal's ^typ
    pfMoreReplacements, ## use more than the default replacements
    pfImportBlackList   ## use import blacklist
  TParser*{.final.} = object
    section: TSection
    inParamList: bool
    context: TContext     # needed for the @emit command
    lastVarSection: PNode
    lex: TLexer
    tok: TToken
    repl: TIdTable           # replacements
    flags: set[TParserFlag]
  
  TReplaceTuple* = array[0..1, string]

const 
  ImportBlackList*: array[1..3, string] = ["nsystem", "sysutils", "charsets"]
  stdReplacements*: array[1..19, TReplaceTuple] = [["include", "incl"], 
    ["exclude", "excl"], ["pchar", "cstring"], ["assignfile", "open"], 
    ["integer", "int"], ["longword", "int32"], ["cardinal", "int"], 
    ["boolean", "bool"], ["shortint", "int8"], ["smallint", "int16"], 
    ["longint", "int32"], ["byte", "int8"], ["word", "int16"], 
    ["single", "float32"], ["double", "float64"], ["real", "float"], 
    ["length", "len"], ["len", "length"], ["setlength", "setlen"]]
  nimReplacements*: array[1..35, TReplaceTuple] = [["nimread", "read"], 
    ["nimwrite", "write"], ["nimclosefile", "close"], ["closefile", "close"], 
    ["openfile", "open"], ["nsystem", "system"], ["ntime", "times"], 
    ["nos", "os"], ["nmath", "math"], ["ncopy", "copy"], ["addChar", "add"], 
    ["halt", "quit"], ["nobject", "TObject"], ["eof", "EndOfFile"], 
    ["input", "stdin"], ["output", "stdout"], ["addu", "`+%`"], 
    ["subu", "`-%`"], ["mulu", "`*%`"], ["divu", "`/%`"], ["modu", "`%%`"], 
    ["ltu", "`<%`"], ["leu", "`<=%`"], ["shlu", "`shl`"], ["shru", "`shr`"], 
    ["assigned", "not isNil"], ["eintoverflow", "EOverflow"], ["format", "`%`"], 
    ["snil", "nil"], ["tostringf", "$"], ["ttextfile", "tfile"], 
    ["tbinaryfile", "tfile"], ["strstart", "0"], ["nl", "\"\\n\""],
    ["tostring", "$"]]

proc ParseUnit*(p: var TParser): PNode
proc openParser*(p: var TParser, filename: string, inputStream: PLLStream,
                 flags: set[TParserFlag] = {})
proc closeParser*(p: var TParser)
proc exSymbol*(n: var PNode)
proc fixRecordDef*(n: var PNode)
  # XXX: move these two to an auxiliary module

# implementation

proc OpenParser(p: var TParser, filename: string, 
                inputStream: PLLStream, flags: set[TParserFlag] = {}) = 
  OpenLexer(p.lex, filename, inputStream)
  initIdTable(p.repl)
  for i in countup(low(stdReplacements), high(stdReplacements)): 
    IdTablePut(p.repl, getIdent(stdReplacements[i][0]), 
               getIdent(stdReplacements[i][1]))
  if pfMoreReplacements in flags: 
    for i in countup(low(nimReplacements), high(nimReplacements)): 
      IdTablePut(p.repl, getIdent(nimReplacements[i][0]), 
                 getIdent(nimReplacements[i][1]))
  p.flags = flags
  
proc CloseParser(p: var TParser) = CloseLexer(p.lex)
proc getTok(p: var TParser) = getTok(p.lex, p.tok)

proc parMessage(p: TParser, msg: TMsgKind, arg = "") = 
  lexMessage(p.lex, msg, arg)

proc parLineInfo(p: TParser): TLineInfo = 
  result = getLineInfo(p.lex)

proc skipCom(p: var TParser, n: PNode) = 
  while p.tok.xkind == pxComment: 
    if (n != nil): 
      if n.comment == nil: n.comment = p.tok.literal
      else: add(n.comment, "\n" & p.tok.literal)
    else: 
      parMessage(p, warnCommentXIgnored, p.tok.literal)
    getTok(p)

proc ExpectIdent(p: TParser) = 
  if p.tok.xkind != pxSymbol: 
    lexMessage(p.lex, errIdentifierExpected, $(p.tok))
  
proc Eat(p: var TParser, xkind: TTokKind) = 
  if p.tok.xkind == xkind: getTok(p)
  else: lexMessage(p.lex, errTokenExpected, TokKindToStr(xkind))
  
proc Opt(p: var TParser, xkind: TTokKind) = 
  if p.tok.xkind == xkind: getTok(p)
  
proc newNodeP(kind: TNodeKind, p: TParser): PNode = 
  result = newNodeI(kind, getLineInfo(p.lex))

proc newIntNodeP(kind: TNodeKind, intVal: BiggestInt, p: TParser): PNode = 
  result = newNodeP(kind, p)
  result.intVal = intVal

proc newFloatNodeP(kind: TNodeKind, floatVal: BiggestFloat, 
                   p: TParser): PNode = 
  result = newNodeP(kind, p)
  result.floatVal = floatVal

proc newStrNodeP(kind: TNodeKind, strVal: string, p: TParser): PNode = 
  result = newNodeP(kind, p)
  result.strVal = strVal

proc newIdentNodeP(ident: PIdent, p: TParser): PNode = 
  result = newNodeP(nkIdent, p)
  result.ident = ident

proc createIdentNodeP(ident: PIdent, p: TParser): PNode = 
  result = newNodeP(nkIdent, p)
  var x = PIdent(IdTableGet(p.repl, ident))
  if x != nil: result.ident = x
  else: result.ident = ident
  
proc parseExpr(p: var TParser): PNode
proc parseStmt(p: var TParser): PNode
proc parseTypeDesc(p: var TParser, definition: PNode = nil): PNode

proc parseEmit(p: var TParser, definition: PNode): PNode = 
  getTok(p)                   # skip 'emit'
  result = ast.emptyNode
  if p.tok.xkind != pxCurlyDirRi: 
    case p.context
    of conExpr: 
      result = parseExpr(p)
    of conStmt: 
      result = parseStmt(p)
      if p.tok.xkind != pxCurlyDirRi: 
        var a = result
        result = newNodeP(nkStmtList, p)
        addSon(result, a)
        while p.tok.xkind != pxCurlyDirRi: 
          addSon(result, parseStmt(p))
    of conTypeDesc: 
      result = parseTypeDesc(p, definition)
  eat(p, pxCurlyDirRi)

proc parseCommand(p: var TParser, definition: PNode = nil): PNode = 
  result = ast.emptyNode
  getTok(p)
  if p.tok.ident.id == getIdent("discard").id: 
    result = newNodeP(nkDiscardStmt, p)
    getTok(p)
    eat(p, pxCurlyDirRi)
    addSon(result, parseExpr(p))
  elif p.tok.ident.id == getIdent("set").id: 
    getTok(p)
    eat(p, pxCurlyDirRi)
    result = parseExpr(p)
    if result.kind == nkEmpty: InternalError("emptyNode modified")
    result.kind = nkCurly
  elif p.tok.ident.id == getIdent("cast").id: 
    getTok(p)
    eat(p, pxCurlyDirRi)
    var a = parseExpr(p)
    if (a.kind == nkCall) and (sonsLen(a) == 2): 
      result = newNodeP(nkCast, p)
      addSon(result, a.sons[0])
      addSon(result, a.sons[1])
    else: 
      parMessage(p, errInvalidDirectiveX, $p.tok)
      result = a
  elif p.tok.ident.id == getIdent("emit").id: 
    result = parseEmit(p, definition)
  elif p.tok.ident.id == getIdent("ignore").id: 
    getTok(p)
    eat(p, pxCurlyDirRi)
    while true: 
      case p.tok.xkind
      of pxEof: 
        parMessage(p, errTokenExpected, "{@emit}")
      of pxCommand: 
        getTok(p)
        if p.tok.ident.id == getIdent("emit").id: 
          result = parseEmit(p, definition)
          break 
        else: 
          while (p.tok.xkind != pxCurlyDirRi) and (p.tok.xkind != pxEof): 
            getTok(p)
          eat(p, pxCurlyDirRi)
      else: 
        getTok(p)             # skip token
  elif p.tok.ident.id == getIdent("ptr").id: 
    result = newNodeP(nkPtrTy, p)
    getTok(p)
    eat(p, pxCurlyDirRi)
  elif p.tok.ident.id == getIdent("tuple").id: 
    result = newNodeP(nkTupleTy, p)
    getTok(p)
    eat(p, pxCurlyDirRi)
  elif p.tok.ident.id == getIdent("acyclic").id: 
    result = newIdentNodeP(p.tok.ident, p)
    getTok(p)
    eat(p, pxCurlyDirRi)
  else: 
    parMessage(p, errInvalidDirectiveX, $p.tok)
    while true: 
      getTok(p)
      if p.tok.xkind == pxCurlyDirRi or p.tok.xkind == pxEof: break 
    eat(p, pxCurlyDirRi)
    result = ast.emptyNode

proc getPrecedence(kind: TTokKind): int = 
  case kind
  of pxDiv, pxMod, pxStar, pxSlash, pxShl, pxShr, pxAnd: result = 5
  of pxPlus, pxMinus, pxOr, pxXor: result = 4
  of pxIn, pxEquals, pxLe, pxLt, pxGe, pxGt, pxNeq, pxIs: result = 3
  else: result = -1
  
proc rangeExpr(p: var TParser): PNode = 
  var a = parseExpr(p)
  if p.tok.xkind == pxDotDot: 
    result = newNodeP(nkRange, p)
    addSon(result, a)
    getTok(p)
    skipCom(p, result)
    addSon(result, parseExpr(p))
  else: 
    result = a
  
proc bracketExprList(p: var TParser, first: PNode): PNode = 
  result = newNodeP(nkBracketExpr, p)
  addSon(result, first)
  getTok(p)
  skipCom(p, result)
  while true: 
    if p.tok.xkind == pxBracketRi: 
      getTok(p)
      break 
    if p.tok.xkind == pxEof: 
      parMessage(p, errTokenExpected, TokKindToStr(pxBracketRi))
      break 
    var a = rangeExpr(p)
    skipCom(p, a)
    if p.tok.xkind == pxComma: 
      getTok(p)
      skipCom(p, a)
    addSon(result, a)

proc exprColonEqExpr(p: var TParser, kind: TNodeKind, 
                     tok: TTokKind): PNode = 
  var a = parseExpr(p)
  if p.tok.xkind == tok: 
    result = newNodeP(kind, p)
    getTok(p)
    skipCom(p, result)
    addSon(result, a)
    addSon(result, parseExpr(p))
  else: 
    result = a
  
proc exprListAux(p: var TParser, elemKind: TNodeKind, 
                 endTok, sepTok: TTokKind, result: PNode) = 
  getTok(p)
  skipCom(p, result)
  while true: 
    if p.tok.xkind == endTok: 
      getTok(p)
      break 
    if p.tok.xkind == pxEof: 
      parMessage(p, errTokenExpected, TokKindToStr(endtok))
      break 
    var a = exprColonEqExpr(p, elemKind, sepTok)
    skipCom(p, a)
    if (p.tok.xkind == pxComma) or (p.tok.xkind == pxSemicolon): 
      getTok(p)
      skipCom(p, a)
    addSon(result, a)

proc qualifiedIdent(p: var TParser): PNode = 
  if p.tok.xkind == pxSymbol: 
    result = createIdentNodeP(p.tok.ident, p)
  else: 
    parMessage(p, errIdentifierExpected, $p.tok)
    return ast.emptyNode
  getTok(p)
  skipCom(p, result)
  if p.tok.xkind == pxDot: 
    getTok(p)
    skipCom(p, result)
    if p.tok.xkind == pxSymbol: 
      var a = result
      result = newNodeI(nkDotExpr, a.info)
      addSon(result, a)
      addSon(result, createIdentNodeP(p.tok.ident, p))
      getTok(p)
    else: 
      parMessage(p, errIdentifierExpected, $p.tok)
  
proc qualifiedIdentListAux(p: var TParser, endTok: TTokKind, 
                           result: PNode) = 
  getTok(p)
  skipCom(p, result)
  while true: 
    if p.tok.xkind == endTok: 
      getTok(p)
      break 
    if p.tok.xkind == pxEof: 
      parMessage(p, errTokenExpected, TokKindToStr(endtok))
      break 
    var a = qualifiedIdent(p)
    skipCom(p, a)
    if p.tok.xkind == pxComma: 
      getTok(p)
      skipCom(p, a)
    addSon(result, a)

proc exprColonEqExprList(p: var TParser, kind, elemKind: TNodeKind, 
                         endTok, sepTok: TTokKind): PNode = 
  result = newNodeP(kind, p)
  exprListAux(p, elemKind, endTok, sepTok, result)

proc setBaseFlags(n: PNode, base: TNumericalBase) = 
  case base
  of base10: nil
  of base2: incl(n.flags, nfBase2)
  of base8: incl(n.flags, nfBase8)
  of base16: incl(n.flags, nfBase16)
  
proc identOrLiteral(p: var TParser): PNode = 
  case p.tok.xkind
  of pxSymbol: 
    result = createIdentNodeP(p.tok.ident, p)
    getTok(p)
  of pxIntLit: 
    result = newIntNodeP(nkIntLit, p.tok.iNumber, p)
    setBaseFlags(result, p.tok.base)
    getTok(p)
  of pxInt64Lit: 
    result = newIntNodeP(nkInt64Lit, p.tok.iNumber, p)
    setBaseFlags(result, p.tok.base)
    getTok(p)
  of pxFloatLit: 
    result = newFloatNodeP(nkFloatLit, p.tok.fNumber, p)
    setBaseFlags(result, p.tok.base)
    getTok(p)
  of pxStrLit: 
    if len(p.tok.literal) != 1: result = newStrNodeP(nkStrLit, p.tok.literal, p)
    else: result = newIntNodeP(nkCharLit, ord(p.tok.literal[0]), p)
    getTok(p)
  of pxNil: 
    result = newNodeP(nkNilLit, p)
    getTok(p)
  of pxParLe: 
    # () constructor
    result = exprColonEqExprList(p, nkPar, nkExprColonExpr, pxParRi, pxColon)
    #if hasSonWith(result, nkExprColonExpr) then
    #  replaceSons(result, nkExprColonExpr, nkExprEqExpr)
    if (sonsLen(result) > 1) and not hasSonWith(result, nkExprColonExpr): 
      result.kind = nkBracket # is an array constructor
  of pxBracketLe: 
    # [] constructor
    result = newNodeP(nkBracket, p)
    getTok(p)
    skipCom(p, result)
    while (p.tok.xkind != pxBracketRi) and (p.tok.xkind != pxEof): 
      var a = rangeExpr(p)
      if a.kind == nkRange: 
        result.kind = nkCurly # it is definitely a set literal
      opt(p, pxComma)
      skipCom(p, a)
      assert(a != nil)
      addSon(result, a)
    eat(p, pxBracketRi)
  of pxCommand: 
    result = parseCommand(p)
  else: 
    parMessage(p, errExprExpected, $(p.tok))
    getTok(p) # we must consume a token here to prevend endless loops!
    result = ast.emptyNode
  if result.kind != nkEmpty: skipCom(p, result)
  
proc primary(p: var TParser): PNode = 
  # prefix operator?
  if (p.tok.xkind == pxNot) or (p.tok.xkind == pxMinus) or
      (p.tok.xkind == pxPlus): 
    result = newNodeP(nkPrefix, p)
    var a = newIdentNodeP(getIdent($p.tok), p)
    addSon(result, a)
    getTok(p)
    skipCom(p, a)
    addSon(result, primary(p))
    return 
  elif p.tok.xkind == pxAt: 
    result = newNodeP(nkAddr, p)
    var a = newIdentNodeP(getIdent($p.tok), p)
    getTok(p)
    if p.tok.xkind == pxBracketLe: 
      result = newNodeP(nkPrefix, p)
      addSon(result, a)
      addSon(result, identOrLiteral(p))
    else: 
      addSon(result, primary(p))
    return 
  result = identOrLiteral(p)
  while true: 
    case p.tok.xkind
    of pxParLe: 
      var a = result
      result = newNodeP(nkCall, p)
      addSon(result, a)
      exprListAux(p, nkExprEqExpr, pxParRi, pxEquals, result)
    of pxDot: 
      var a = result
      result = newNodeP(nkDotExpr, p)
      addSon(result, a)
      getTok(p)               # skip '.'
      skipCom(p, result)
      if p.tok.xkind == pxSymbol: 
        addSon(result, createIdentNodeP(p.tok.ident, p))
        getTok(p)
      else: 
        parMessage(p, errIdentifierExpected, $p.tok)
    of pxHat: 
      var a = result
      result = newNodeP(nkBracketExpr, p)
      addSon(result, a)
      getTok(p)
    of pxBracketLe: 
      result = bracketExprList(p, result)
    else: break 
  
proc lowestExprAux(p: var TParser, v: var PNode, limit: int): TTokKind = 
  var 
    nextop: TTokKind
    v2, node, opNode: PNode
  v = primary(p) # expand while operators have priorities higher than 'limit'
  var op = p.tok.xkind
  var opPred = getPrecedence(op)
  while (opPred > limit): 
    node = newNodeP(nkInfix, p)
    opNode = newIdentNodeP(getIdent($(p.tok)), p) # skip operator:
    getTok(p)
    case op
    of pxPlus: 
      case p.tok.xkind
      of pxPer: 
        getTok(p)
        eat(p, pxCurlyDirRi)
        opNode.ident = getIdent("+%")
      of pxAmp: 
        getTok(p)
        eat(p, pxCurlyDirRi)
        opNode.ident = getIdent("&")
      else: 
        nil
    of pxMinus: 
      if p.tok.xkind == pxPer: 
        getTok(p)
        eat(p, pxCurlyDirRi)
        opNode.ident = getIdent("-%")
    of pxEquals: 
      opNode.ident = getIdent("==")
    of pxNeq: 
      opNode.ident = getIdent("!=")
    else: 
      nil
    skipCom(p, opNode)        # read sub-expression with higher priority
    nextop = lowestExprAux(p, v2, opPred)
    addSon(node, opNode)
    addSon(node, v)
    addSon(node, v2)
    v = node
    op = nextop
    opPred = getPrecedence(nextop)
  result = op                 # return first untreated operator
  
proc fixExpr(n: PNode): PNode = 
  result = n
  case n.kind
  of nkInfix: 
    if n.sons[1].kind == nkBracket: n.sons[1].kind = nkCurly
    if n.sons[2].kind == nkBracket: n.sons[2].kind = nkCurly
    if (n.sons[0].kind == nkIdent): 
      if (n.sons[0].ident.id == getIdent("+").id): 
        if (n.sons[1].kind == nkCharLit) and (n.sons[2].kind == nkStrLit) and
            (n.sons[2].strVal == ""): 
          result = newStrNode(nkStrLit, chr(int(n.sons[1].intVal)) & "")
          result.info = n.info
          return              # do not process sons as they don't exist anymore
        elif (n.sons[1].kind in {nkCharLit, nkStrLit}) or
            (n.sons[2].kind in {nkCharLit, nkStrLit}): 
          n.sons[0].ident = getIdent("&") # fix operator
  else: 
    nil
  if not (n.kind in {nkEmpty..nkNilLit}): 
    for i in countup(0, sonsLen(n) - 1): result.sons[i] = fixExpr(n.sons[i])
  
proc parseExpr(p: var TParser): PNode = 
  var oldcontext = p.context
  p.context = conExpr
  if p.tok.xkind == pxCommand: 
    result = parseCommand(p)
  else: 
    discard lowestExprAux(p, result, - 1)
    result = fixExpr(result)
  p.context = oldcontext

proc parseExprStmt(p: var TParser): PNode = 
  var info = parLineInfo(p)
  var a = parseExpr(p)
  if p.tok.xkind == pxAsgn: 
    getTok(p)
    skipCom(p, a)
    var b = parseExpr(p)
    result = newNodeI(nkAsgn, info)
    addSon(result, a)
    addSon(result, b)
  else: 
    result = a
  
proc inImportBlackList(ident: PIdent): bool = 
  for i in countup(low(ImportBlackList), high(ImportBlackList)): 
    if ident.id == getIdent(ImportBlackList[i]).id: 
      return true

proc parseUsesStmt(p: var TParser): PNode = 
  var a: PNode
  result = newNodeP(nkImportStmt, p)
  getTok(p)                   # skip `import`
  skipCom(p, result)
  while true: 
    case p.tok.xkind
    of pxEof: break 
    of pxSymbol: a = newIdentNodeP(p.tok.ident, p)
    else: 
      parMessage(p, errIdentifierExpected, $(p.tok))
      break 
    getTok(p)                 # skip identifier, string
    skipCom(p, a)
    if pfImportBlackList notin p.flags or not inImportBlackList(a.ident): 
      addSon(result, createIdentNodeP(a.ident, p))
    if p.tok.xkind == pxComma: 
      getTok(p)
      skipCom(p, a)
    else: 
      break 
  if sonsLen(result) == 0: result = ast.emptyNode
  
proc parseIncludeDir(p: var TParser): PNode = 
  result = newNodeP(nkIncludeStmt, p)
  getTok(p)                   # skip `include`
  var filename = ""
  while true: 
    case p.tok.xkind
    of pxSymbol, pxDot, pxDotDot, pxSlash: 
      add(filename, $p.tok)
      getTok(p)
    of pxStrLit: 
      filename = p.tok.literal
      getTok(p)
      break 
    of pxCurlyDirRi: 
      break 
    else: 
      parMessage(p, errIdentifierExpected, $p.tok)
      break 
  addSon(result, newStrNodeP(nkStrLit, changeFileExt(filename, "nim"), p))
  if filename == "config.inc": result = ast.emptyNode
  
proc definedExprAux(p: var TParser): PNode = 
  result = newNodeP(nkCall, p)
  addSon(result, newIdentNodeP(getIdent("defined"), p))
  ExpectIdent(p)
  addSon(result, createIdentNodeP(p.tok.ident, p))
  getTok(p)

proc isHandledDirective(p: TParser): bool = 
  if p.tok.xkind in {pxCurlyDirLe, pxStarDirLe}: 
    case toLower(p.tok.ident.s)
    of "else", "endif": result = false
    else: result = true
  
proc parseStmtList(p: var TParser): PNode = 
  result = newNodeP(nkStmtList, p)
  while true: 
    case p.tok.xkind
    of pxEof: 
      break 
    of pxCurlyDirLe, pxStarDirLe: 
      if not isHandledDirective(p): break 
    else: 
      nil
    addSon(result, parseStmt(p))
  if sonsLen(result) == 1: result = result.sons[0]
  
proc parseIfDirAux(p: var TParser, result: PNode) = 
  addSon(result.sons[0], parseStmtList(p))
  if p.tok.xkind in {pxCurlyDirLe, pxStarDirLe}: 
    var endMarker = succ(p.tok.xkind)
    if toLower(p.tok.ident.s) == "else": 
      var s = newNodeP(nkElse, p)
      while p.tok.xkind != pxEof and p.tok.xkind != endMarker: getTok(p)
      eat(p, endMarker)
      addSon(s, parseStmtList(p))
      addSon(result, s)
    if p.tok.xkind in {pxCurlyDirLe, pxStarDirLe}: 
      endMarker = succ(p.tok.xkind)
      if toLower(p.tok.ident.s) == "endif": 
        while p.tok.xkind != pxEof and p.tok.xkind != endMarker: getTok(p)
        eat(p, endMarker)
      else: 
        parMessage(p, errXExpected, "{$endif}")
  else: 
    parMessage(p, errXExpected, "{$endif}")
  
proc parseIfdefDir(p: var TParser, endMarker: TTokKind): PNode = 
  result = newNodeP(nkWhenStmt, p)
  addSon(result, newNodeP(nkElifBranch, p))
  getTok(p)
  addSon(result.sons[0], definedExprAux(p))
  eat(p, endMarker)
  parseIfDirAux(p, result)

proc parseIfndefDir(p: var TParser, endMarker: TTokKind): PNode = 
  result = newNodeP(nkWhenStmt, p)
  addSon(result, newNodeP(nkElifBranch, p))
  getTok(p)
  var e = newNodeP(nkCall, p)
  addSon(e, newIdentNodeP(getIdent("not"), p))
  addSon(e, definedExprAux(p))
  eat(p, endMarker)
  addSon(result.sons[0], e)
  parseIfDirAux(p, result)

proc parseIfDir(p: var TParser, endMarker: TTokKind): PNode = 
  result = newNodeP(nkWhenStmt, p)
  addSon(result, newNodeP(nkElifBranch, p))
  getTok(p)
  addSon(result.sons[0], parseExpr(p))
  eat(p, endMarker)
  parseIfDirAux(p, result)

proc parseDirective(p: var TParser): PNode = 
  result = ast.emptyNode
  if not (p.tok.xkind in {pxCurlyDirLe, pxStarDirLe}): return 
  var endMarker = succ(p.tok.xkind)
  if p.tok.ident != nil: 
    case toLower(p.tok.ident.s)
    of "include": 
      result = parseIncludeDir(p)
      eat(p, endMarker)
    of "if": result = parseIfDir(p, endMarker)
    of "ifdef": result = parseIfdefDir(p, endMarker)
    of "ifndef": result = parseIfndefDir(p, endMarker)
    else: 
      # skip unknown compiler directive
      while p.tok.xkind != pxEof and p.tok.xkind != endMarker: getTok(p)
      eat(p, endMarker)
  else: 
    eat(p, endMarker)
  
proc parseRaise(p: var TParser): PNode = 
  result = newNodeP(nkRaiseStmt, p)
  getTok(p)
  skipCom(p, result)
  if p.tok.xkind != pxSemicolon: addSon(result, parseExpr(p))
  else: addSon(result, ast.emptyNode)
  
proc parseIf(p: var TParser): PNode = 
  result = newNodeP(nkIfStmt, p)
  while true: 
    getTok(p)                 # skip ``if``
    var branch = newNodeP(nkElifBranch, p)
    skipCom(p, branch)
    addSon(branch, parseExpr(p))
    eat(p, pxThen)
    skipCom(p, branch)
    addSon(branch, parseStmt(p))
    skipCom(p, branch)
    addSon(result, branch)
    if p.tok.xkind == pxElse: 
      getTok(p)
      if p.tok.xkind != pxIf: 
        # ordinary else part:
        branch = newNodeP(nkElse, p)
        skipCom(p, result)    # BUGFIX
        addSon(branch, parseStmt(p))
        addSon(result, branch)
        break 
    else: 
      break 
  
proc parseWhile(p: var TParser): PNode = 
  result = newNodeP(nkWhileStmt, p)
  getTok(p)
  skipCom(p, result)
  addSon(result, parseExpr(p))
  eat(p, pxDo)
  skipCom(p, result)
  addSon(result, parseStmt(p))

proc parseRepeat(p: var TParser): PNode = 
  result = newNodeP(nkWhileStmt, p)
  getTok(p)
  skipCom(p, result)
  addSon(result, newIdentNodeP(getIdent("true"), p))
  var s = newNodeP(nkStmtList, p)
  while p.tok.xkind != pxEof and p.tok.xkind != pxUntil: 
    addSon(s, parseStmt(p))
  eat(p, pxUntil)
  var a = newNodeP(nkIfStmt, p)
  skipCom(p, a)
  var b = newNodeP(nkElifBranch, p)
  var c = newNodeP(nkBreakStmt, p)
  addSon(c, ast.emptyNode)
  addSon(b, parseExpr(p))
  skipCom(p, a)
  addSon(b, c)
  addSon(a, b)
  if b.sons[0].kind == nkIdent and b.sons[0].ident.id == getIdent("false").id: 
    nil
  else: 
    addSon(s, a)
  addSon(result, s)

proc parseCase(p: var TParser): PNode = 
  var b: PNode
  result = newNodeP(nkCaseStmt, p)
  getTok(p)
  addSon(result, parseExpr(p))
  eat(p, pxOf)
  skipCom(p, result)
  while (p.tok.xkind != pxEnd) and (p.tok.xkind != pxEof): 
    if p.tok.xkind == pxElse: 
      b = newNodeP(nkElse, p)
      getTok(p)
    else: 
      b = newNodeP(nkOfBranch, p)
      while (p.tok.xkind != pxEof) and (p.tok.xkind != pxColon): 
        addSon(b, rangeExpr(p))
        opt(p, pxComma)
        skipcom(p, b)
      eat(p, pxColon)
    skipCom(p, b)
    addSon(b, parseStmt(p))
    addSon(result, b)
    if b.kind == nkElse: break 
  eat(p, pxEnd)

proc parseTry(p: var TParser): PNode = 
  result = newNodeP(nkTryStmt, p)
  getTok(p)
  skipCom(p, result)
  var b = newNodeP(nkStmtList, p)
  while not (p.tok.xkind in {pxFinally, pxExcept, pxEof, pxEnd}): 
    addSon(b, parseStmt(p))
  addSon(result, b)
  if p.tok.xkind == pxExcept: 
    getTok(p)
    while p.tok.ident.id == getIdent("on").id: 
      b = newNodeP(nkExceptBranch, p)
      getTok(p)
      var e = qualifiedIdent(p)
      if p.tok.xkind == pxColon: 
        getTok(p)
        e = qualifiedIdent(p)
      addSon(b, e)
      eat(p, pxDo)
      addSon(b, parseStmt(p))
      addSon(result, b)
      if p.tok.xkind == pxCommand: discard parseCommand(p)
    if p.tok.xkind == pxElse: 
      b = newNodeP(nkExceptBranch, p)
      getTok(p)
      addSon(b, parseStmt(p))
      addSon(result, b)
  if p.tok.xkind == pxFinally: 
    b = newNodeP(nkFinally, p)
    getTok(p)
    var e = newNodeP(nkStmtList, p)
    while (p.tok.xkind != pxEof) and (p.tok.xkind != pxEnd): 
      addSon(e, parseStmt(p))
    if sonsLen(e) == 0: addSon(e, newNodeP(nkNilLit, p))
    addSon(result, e)
  eat(p, pxEnd)

proc parseFor(p: var TParser): PNode = 
  result = newNodeP(nkForStmt, p)
  getTok(p)
  skipCom(p, result)
  expectIdent(p)
  addSon(result, createIdentNodeP(p.tok.ident, p))
  getTok(p)
  eat(p, pxAsgn)
  var a = parseExpr(p)
  var b = ast.emptyNode
  var c = newNodeP(nkCall, p)
  if p.tok.xkind == pxTo: 
    addSon(c, newIdentNodeP(getIdent("countup"), p))
    getTok(p)
    b = parseExpr(p)
  elif p.tok.xkind == pxDownto: 
    addSon(c, newIdentNodeP(getIdent("countdown"), p))
    getTok(p)
    b = parseExpr(p)
  else: 
    parMessage(p, errTokenExpected, TokKindToStr(pxTo))
  addSon(c, a)
  addSon(c, b)
  eat(p, pxDo)
  skipCom(p, result)
  addSon(result, c)
  addSon(result, parseStmt(p))

proc parseParam(p: var TParser): PNode = 
  var a: PNode
  result = newNodeP(nkIdentDefs, p)
  var v = ast.emptyNode
  case p.tok.xkind
  of pxConst: 
    getTok(p)
  of pxVar: 
    getTok(p)
    v = newNodeP(nkVarTy, p)
  of pxOut: 
    getTok(p)
    v = newNodeP(nkVarTy, p)
  else: 
    nil
  while true: 
    case p.tok.xkind
    of pxSymbol: a = createIdentNodeP(p.tok.ident, p)
    of pxColon, pxEof, pxParRi, pxEquals: break 
    else: 
      parMessage(p, errIdentifierExpected, $p.tok)
      return 
    getTok(p)                 # skip identifier
    skipCom(p, a)
    if p.tok.xkind == pxComma: 
      getTok(p)
      skipCom(p, a)
    addSon(result, a)
  if p.tok.xkind == pxColon: 
    getTok(p)
    skipCom(p, result)
    if v.kind != nkEmpty: addSon(v, parseTypeDesc(p))
    else: v = parseTypeDesc(p)
    addSon(result, v)
  else: 
    addSon(result, ast.emptyNode)
    if p.tok.xkind != pxEquals: 
      parMessage(p, errColonOrEqualsExpected, $p.tok)
  if p.tok.xkind == pxEquals: 
    getTok(p)
    skipCom(p, result)
    addSon(result, parseExpr(p))
  else: 
    addSon(result, ast.emptyNode)
  
proc parseParamList(p: var TParser): PNode = 
  var a: PNode
  result = newNodeP(nkFormalParams, p)
  addSon(result, ast.emptyNode)         # return type
  if p.tok.xkind == pxParLe: 
    p.inParamList = true
    getTok(p)
    skipCom(p, result)
    while true: 
      case p.tok.xkind
      of pxSymbol, pxConst, pxVar, pxOut: 
        a = parseParam(p)
      of pxParRi: 
        getTok(p)
        break 
      else: 
        parMessage(p, errTokenExpected, ")")
        break 
      skipCom(p, a)
      if p.tok.xkind == pxSemicolon: 
        getTok(p)
        skipCom(p, a)
      addSon(result, a)
    p.inParamList = false
  if p.tok.xkind == pxColon: 
    getTok(p)
    skipCom(p, result)
    result.sons[0] = parseTypeDesc(p)

proc parseCallingConvention(p: var TParser): PNode = 
  result = ast.emptyNode
  if p.tok.xkind == pxSymbol: 
    case toLower(p.tok.ident.s)
    of "stdcall", "cdecl", "safecall", "syscall", "inline", "fastcall": 
      result = newNodeP(nkPragma, p)
      addSon(result, newIdentNodeP(p.tok.ident, p))
      getTok(p)
      opt(p, pxSemicolon)
    of "register": 
      result = newNodeP(nkPragma, p)
      addSon(result, newIdentNodeP(getIdent("fastcall"), p))
      getTok(p)
      opt(p, pxSemicolon)
    else: 
      nil

proc parseRoutineSpecifiers(p: var TParser, noBody: var bool): PNode = 
  var e: PNode
  result = parseCallingConvention(p)
  noBody = false
  while p.tok.xkind == pxSymbol: 
    case toLower(p.tok.ident.s)
    of "assembler", "overload", "far": 
      getTok(p)
      opt(p, pxSemicolon)
    of "forward": 
      noBody = true
      getTok(p)
      opt(p, pxSemicolon)
    of "importc": 
      # This is a fake for platform module. There is no ``importc``
      # directive in Pascal.
      if result.kind == nkEmpty: result = newNodeP(nkPragma, p)
      addSon(result, newIdentNodeP(getIdent("importc"), p))
      noBody = true
      getTok(p)
      opt(p, pxSemicolon)
    of "noconv": 
      # This is a fake for platform module. There is no ``noconv``
      # directive in Pascal.
      if result.kind == nkEmpty: result = newNodeP(nkPragma, p)
      addSon(result, newIdentNodeP(getIdent("noconv"), p))
      noBody = true
      getTok(p)
      opt(p, pxSemicolon)
    of "procvar": 
      # This is a fake for the Nimrod compiler. There is no ``procvar``
      # directive in Pascal.
      if result.kind == nkEmpty: result = newNodeP(nkPragma, p)
      addSon(result, newIdentNodeP(getIdent("procvar"), p))
      getTok(p)
      opt(p, pxSemicolon)
    of "varargs": 
      if result.kind == nkEmpty: result = newNodeP(nkPragma, p)
      addSon(result, newIdentNodeP(getIdent("varargs"), p))
      getTok(p)
      opt(p, pxSemicolon)
    of "external": 
      if result.kind == nkEmpty: result = newNodeP(nkPragma, p)
      getTok(p)
      noBody = true
      e = newNodeP(nkExprColonExpr, p)
      addSon(e, newIdentNodeP(getIdent("dynlib"), p))
      addSon(e, parseExpr(p))
      addSon(result, e)
      opt(p, pxSemicolon)
      if (p.tok.xkind == pxSymbol) and
          (p.tok.ident.id == getIdent("name").id): 
        e = newNodeP(nkExprColonExpr, p)
        getTok(p)
        addSon(e, newIdentNodeP(getIdent("importc"), p))
        addSon(e, parseExpr(p))
        addSon(result, e)
      else: 
        addSon(result, newIdentNodeP(getIdent("importc"), p))
      opt(p, pxSemicolon)
    else: 
      e = parseCallingConvention(p)
      if e.kind == nkEmpty: break 
      if result.kind == nkEmpty: result = newNodeP(nkPragma, p)
      addSon(result, e.sons[0])

proc parseRoutineType(p: var TParser): PNode = 
  result = newNodeP(nkProcTy, p)
  getTok(p)
  skipCom(p, result)
  addSon(result, parseParamList(p))
  opt(p, pxSemicolon)
  addSon(result, parseCallingConvention(p))
  skipCom(p, result)

proc parseEnum(p: var TParser): PNode = 
  var a: PNode
  result = newNodeP(nkEnumTy, p)
  getTok(p)
  skipCom(p, result)
  addSon(result, ast.emptyNode) # it does not inherit from any enumeration
  while true: 
    case p.tok.xkind
    of pxEof, pxParRi: break 
    of pxSymbol: a = newIdentNodeP(p.tok.ident, p)
    else: 
      parMessage(p, errIdentifierExpected, $(p.tok))
      break 
    getTok(p)                 # skip identifier
    skipCom(p, a)
    if (p.tok.xkind == pxEquals) or (p.tok.xkind == pxAsgn): 
      getTok(p)
      skipCom(p, a)
      var b = a
      a = newNodeP(nkEnumFieldDef, p)
      addSon(a, b)
      addSon(a, parseExpr(p))
    if p.tok.xkind == pxComma: 
      getTok(p)
      skipCom(p, a)
    addSon(result, a)
  eat(p, pxParRi)

proc identVis(p: var TParser): PNode = 
  # identifier with visability
  var a = createIdentNodeP(p.tok.ident, p)
  if p.section == seInterface: 
    result = newNodeP(nkPostfix, p)
    addSon(result, newIdentNodeP(getIdent("*"), p))
    addSon(result, a)
  else: 
    result = a
  getTok(p)

type 
  TSymbolParser = proc (p: var TParser): PNode

proc rawIdent(p: var TParser): PNode = 
  result = createIdentNodeP(p.tok.ident, p)
  getTok(p)

proc parseIdentColonEquals(p: var TParser, 
                           identParser: TSymbolParser): PNode = 
  var a: PNode
  result = newNodeP(nkIdentDefs, p)
  while true: 
    case p.tok.xkind
    of pxSymbol: a = identParser(p)
    of pxColon, pxEof, pxParRi, pxEquals: break 
    else: 
      parMessage(p, errIdentifierExpected, $(p.tok))
      return 
    skipCom(p, a)
    if p.tok.xkind == pxComma: 
      getTok(p)
      skipCom(p, a)
    addSon(result, a)
  if p.tok.xkind == pxColon: 
    getTok(p)
    skipCom(p, result)
    addSon(result, parseTypeDesc(p))
  else: 
    addSon(result, ast.emptyNode)
    if p.tok.xkind != pxEquals: 
      parMessage(p, errColonOrEqualsExpected, $(p.tok))
  if p.tok.xkind == pxEquals: 
    getTok(p)
    skipCom(p, result)
    addSon(result, parseExpr(p))
  else: 
    addSon(result, ast.emptyNode)
  if p.tok.xkind == pxSemicolon: 
    getTok(p)
    skipCom(p, result)

proc parseRecordCase(p: var TParser): PNode = 
  var b, c: PNode
  result = newNodeP(nkRecCase, p)
  getTok(p)
  var a = newNodeP(nkIdentDefs, p)
  addSon(a, rawIdent(p))
  eat(p, pxColon)
  addSon(a, parseTypeDesc(p))
  addSon(a, ast.emptyNode)
  addSon(result, a)
  eat(p, pxOf)
  skipCom(p, result)
  while true: 
    case p.tok.xkind
    of pxEof, pxEnd: 
      break 
    of pxElse: 
      b = newNodeP(nkElse, p)
      getTok(p)
    else: 
      b = newNodeP(nkOfBranch, p)
      while (p.tok.xkind != pxEof) and (p.tok.xkind != pxColon): 
        addSon(b, rangeExpr(p))
        opt(p, pxComma)
        skipcom(p, b)
      eat(p, pxColon)
    skipCom(p, b)
    c = newNodeP(nkRecList, p)
    eat(p, pxParLe)
    while (p.tok.xkind != pxParRi) and (p.tok.xkind != pxEof): 
      addSon(c, parseIdentColonEquals(p, rawIdent))
      opt(p, pxSemicolon)
      skipCom(p, lastSon(c))
    eat(p, pxParRi)
    opt(p, pxSemicolon)
    if sonsLen(c) > 0: skipCom(p, lastSon(c))
    else: addSon(c, newNodeP(nkNilLit, p))
    addSon(b, c)
    addSon(result, b)
    if b.kind == nkElse: break 
  
proc parseRecordPart(p: var TParser): PNode = 
  result = ast.emptyNode
  while (p.tok.xkind != pxEof) and (p.tok.xkind != pxEnd): 
    if result.kind == nkEmpty: result = newNodeP(nkRecList, p)
    case p.tok.xkind
    of pxSymbol: 
      addSon(result, parseIdentColonEquals(p, rawIdent))
      opt(p, pxSemicolon)
      skipCom(p, lastSon(result))
    of pxCase: 
      addSon(result, parseRecordCase(p))
    of pxComment: 
      skipCom(p, lastSon(result))
    else: 
      parMessage(p, errIdentifierExpected, $p.tok)
      break

proc exSymbol(n: var PNode) = 
  case n.kind
  of nkPostfix: 
    nil
  of nkPragmaExpr: 
    exSymbol(n.sons[0])
  of nkIdent, nkAccQuoted: 
    var a = newNodeI(nkPostFix, n.info)
    addSon(a, newIdentNode(getIdent("*"), n.info))
    addSon(a, n)
    n = a
  else: internalError(n.info, "exSymbol(): " & $n.kind)
  
proc fixRecordDef(n: var PNode) = 
  case n.kind
  of nkRecCase: 
    fixRecordDef(n.sons[0])
    for i in countup(1, sonsLen(n) - 1): 
      var length = sonsLen(n.sons[i])
      fixRecordDef(n.sons[i].sons[length - 1])
  of nkRecList, nkRecWhen, nkElse, nkOfBranch, nkElifBranch, nkObjectTy: 
    for i in countup(0, sonsLen(n) - 1): fixRecordDef(n.sons[i])
  of nkIdentDefs: 
    for i in countup(0, sonsLen(n) - 3): exSymbol(n.sons[i])
  of nkNilLit, nkEmpty: nil
  else: internalError(n.info, "fixRecordDef(): " & $n.kind)
  
proc addPragmaToIdent(ident: var PNode, pragma: PNode) = 
  var pragmasNode: PNode
  if ident.kind != nkPragmaExpr: 
    pragmasNode = newNodeI(nkPragma, ident.info)
    var e = newNodeI(nkPragmaExpr, ident.info)
    addSon(e, ident)
    addSon(e, pragmasNode)
    ident = e
  else: 
    pragmasNode = ident.sons[1]
    if pragmasNode.kind != nkPragma: 
      InternalError(ident.info, "addPragmaToIdent")
  addSon(pragmasNode, pragma)

proc parseRecordBody(p: var TParser, result, definition: PNode) = 
  skipCom(p, result)
  var a = parseRecordPart(p)
  if result.kind != nkTupleTy: fixRecordDef(a)
  addSon(result, a)
  eat(p, pxEnd)
  case p.tok.xkind
  of pxSymbol: 
    if p.tok.ident.id == getIdent("acyclic").id: 
      if definition != nil: 
        addPragmaToIdent(definition.sons[0], newIdentNodeP(p.tok.ident, p))
      else: 
        InternalError(result.info, "anonymous record is not supported")
      getTok(p)
    else: 
      InternalError(result.info, "parseRecordBody")
  of pxCommand: 
    if definition != nil: addPragmaToIdent(definition.sons[0], parseCommand(p))
    else: InternalError(result.info, "anonymous record is not supported")
  else: 
    nil
  opt(p, pxSemicolon)
  skipCom(p, result)

proc parseRecordOrObject(p: var TParser, kind: TNodeKind, 
                         definition: PNode): PNode = 
  result = newNodeP(kind, p)
  getTok(p)
  addSon(result, ast.emptyNode)
  if p.tok.xkind == pxParLe: 
    var a = newNodeP(nkOfInherit, p)
    getTok(p)
    addSon(a, parseTypeDesc(p))
    addSon(result, a)
    eat(p, pxParRi)
  else: 
    addSon(result, ast.emptyNode)
  parseRecordBody(p, result, definition)

proc parseTypeDesc(p: var TParser, definition: PNode = nil): PNode = 
  var oldcontext = p.context
  p.context = conTypeDesc
  if p.tok.xkind == pxPacked: getTok(p)
  case p.tok.xkind
  of pxCommand: 
    result = parseCommand(p, definition)
  of pxProcedure, pxFunction: 
    result = parseRoutineType(p)
  of pxRecord: 
    getTok(p)
    if p.tok.xkind == pxCommand: 
      result = parseCommand(p)
      if result.kind != nkTupleTy: InternalError(result.info, "parseTypeDesc")
      parseRecordBody(p, result, definition)
      var a = lastSon(result)     # embed nkRecList directly into nkTupleTy
      for i in countup(0, sonsLen(a) - 1): 
        if i == 0: result.sons[sonsLen(result) - 1] = a.sons[0]
        else: addSon(result, a.sons[i])
    else: 
      result = newNodeP(nkObjectTy, p)
      addSon(result, ast.emptyNode)
      addSon(result, ast.emptyNode)
      parseRecordBody(p, result, definition)
      if definition != nil: 
        addPragmaToIdent(definition.sons[0], newIdentNodeP(getIdent("final"), p))
      else: 
        InternalError(result.info, "anonymous record is not supported")
  of pxObject: result = parseRecordOrObject(p, nkObjectTy, definition)
  of pxParLe: result = parseEnum(p)
  of pxArray: 
    result = newNodeP(nkBracketExpr, p)
    getTok(p)
    if p.tok.xkind == pxBracketLe: 
      addSon(result, newIdentNodeP(getIdent("array"), p))
      getTok(p)
      addSon(result, rangeExpr(p))
      eat(p, pxBracketRi)
    else: 
      if p.inParamList: addSon(result, newIdentNodeP(getIdent("openarray"), p))
      else: addSon(result, newIdentNodeP(getIdent("seq"), p))
    eat(p, pxOf)
    addSon(result, parseTypeDesc(p))
  of pxSet: 
    result = newNodeP(nkBracketExpr, p)
    getTok(p)
    eat(p, pxOf)
    addSon(result, newIdentNodeP(getIdent("set"), p))
    addSon(result, parseTypeDesc(p))
  of pxHat: 
    getTok(p)
    if p.tok.xkind == pxCommand: result = parseCommand(p)
    elif pfRefs in p.flags: result = newNodeP(nkRefTy, p)
    else: result = newNodeP(nkPtrTy, p)
    addSon(result, parseTypeDesc(p))
  of pxType: 
    getTok(p)
    result = parseTypeDesc(p)
  else: 
    var a = primary(p)
    if p.tok.xkind == pxDotDot: 
      result = newNodeP(nkBracketExpr, p)
      var r = newNodeP(nkRange, p)
      addSon(result, newIdentNodeP(getIdent("range"), p))
      getTok(p)
      addSon(r, a)
      addSon(r, parseExpr(p))
      addSon(result, r)
    else: 
      result = a
  p.context = oldcontext

proc parseTypeDef(p: var TParser): PNode = 
  result = newNodeP(nkTypeDef, p)
  addSon(result, identVis(p))
  addSon(result, ast.emptyNode)         # generic params
  if p.tok.xkind == pxEquals: 
    getTok(p)
    skipCom(p, result)
    addSon(result, parseTypeDesc(p, result))
  else: 
    addSon(result, ast.emptyNode)
  if p.tok.xkind == pxSemicolon: 
    getTok(p)
    skipCom(p, result)

proc parseTypeSection(p: var TParser): PNode = 
  result = newNodeP(nkTypeSection, p)
  getTok(p)
  skipCom(p, result)
  while p.tok.xkind == pxSymbol: 
    addSon(result, parseTypeDef(p))

proc parseConstant(p: var TParser): PNode = 
  result = newNodeP(nkConstDef, p)
  addSon(result, identVis(p))
  if p.tok.xkind == pxColon: 
    getTok(p)
    skipCom(p, result)
    addSon(result, parseTypeDesc(p))
  else: 
    addSon(result, ast.emptyNode)
    if p.tok.xkind != pxEquals: 
      parMessage(p, errColonOrEqualsExpected, $(p.tok))
  if p.tok.xkind == pxEquals: 
    getTok(p)
    skipCom(p, result)
    addSon(result, parseExpr(p))
  else: 
    addSon(result, ast.emptyNode)
  if p.tok.xkind == pxSemicolon: 
    getTok(p)
    skipCom(p, result)

proc parseConstSection(p: var TParser): PNode = 
  result = newNodeP(nkConstSection, p)
  getTok(p)
  skipCom(p, result)
  while p.tok.xkind == pxSymbol: 
    addSon(result, parseConstant(p))

proc parseVar(p: var TParser): PNode = 
  result = newNodeP(nkVarSection, p)
  getTok(p)
  skipCom(p, result)
  while p.tok.xkind == pxSymbol:
    addSon(result, parseIdentColonEquals(p, identVis))
  p.lastVarSection = result

proc parseRoutine(p: var TParser): PNode = 
  var noBody: bool
  result = newNodeP(nkProcDef, p)
  getTok(p)
  skipCom(p, result)
  expectIdent(p)
  addSon(result, identVis(p))
  addSon(result, ast.emptyNode)         # generic parameters
  addSon(result, parseParamList(p))
  opt(p, pxSemicolon)
  addSon(result, parseRoutineSpecifiers(p, noBody))
  if (p.section == seInterface) or noBody: 
    addSon(result, ast.emptyNode)
  else: 
    var stmts = newNodeP(nkStmtList, p)
    while true: 
      case p.tok.xkind
      of pxVar: addSon(stmts, parseVar(p))
      of pxConst: addSon(stmts, parseConstSection(p))
      of pxType: addSon(stmts, parseTypeSection(p))
      of pxComment: skipCom(p, result)
      of pxBegin: break 
      else: 
        parMessage(p, errTokenExpected, "begin")
        break 
    var a = parseStmt(p)
    for i in countup(0, sonsLen(a) - 1): addSon(stmts, a.sons[i])
    addSon(result, stmts)

proc fixExit(p: var TParser, n: PNode): bool = 
  if (p.tok.ident.id == getIdent("exit").id): 
    var length = sonsLen(n)
    if (length <= 0): return 
    var a = n.sons[length-1]
    if (a.kind == nkAsgn) and (a.sons[0].kind == nkIdent) and
        (a.sons[0].ident.id == getIdent("result").id): 
      delSon(a, 0)
      a.kind = nkReturnStmt
      result = true
      getTok(p)
      opt(p, pxSemicolon)
      skipCom(p, a)

proc fixVarSection(p: var TParser, counter: PNode) = 
  if p.lastVarSection == nil: return 
  assert(counter.kind == nkIdent)
  for i in countup(0, sonsLen(p.lastVarSection) - 1): 
    var v = p.lastVarSection.sons[i]
    for j in countup(0, sonsLen(v) - 3): 
      if v.sons[j].ident.id == counter.ident.id: 
        delSon(v, j)
        if sonsLen(v) <= 2: 
          delSon(p.lastVarSection, i)
        return 

proc exSymbols(n: PNode) = 
  case n.kind
  of nkEmpty..nkNilLit: nil
  of nkProcDef..nkIteratorDef: exSymbol(n.sons[namePos])
  of nkWhenStmt, nkStmtList: 
    for i in countup(0, sonsLen(n) - 1): exSymbols(n.sons[i])
  of nkVarSection, nkConstSection: 
    for i in countup(0, sonsLen(n) - 1): exSymbol(n.sons[i].sons[0])
  of nkTypeSection: 
    for i in countup(0, sonsLen(n) - 1): 
      exSymbol(n.sons[i].sons[0])
      if n.sons[i].sons[2].kind == nkObjectTy: 
        fixRecordDef(n.sons[i].sons[2])
  else: nil

proc parseBegin(p: var TParser, result: PNode) = 
  getTok(p)
  while true: 
    case p.tok.xkind
    of pxComment: addSon(result, parseStmt(p))
    of pxSymbol: 
      if not fixExit(p, result): addSon(result, parseStmt(p))
    of pxEnd: 
      getTok(p)
      break 
    of pxSemicolon: getTok(p)
    of pxEof: parMessage(p, errExprExpected)
    else: 
      var a = parseStmt(p)
      if a.kind != nkEmpty: addSon(result, a)
  if sonsLen(result) == 0: addSon(result, newNodeP(nkNilLit, p))
  
proc parseStmt(p: var TParser): PNode = 
  var oldcontext = p.context
  p.context = conStmt
  result = ast.emptyNode
  case p.tok.xkind
  of pxBegin: 
    result = newNodeP(nkStmtList, p)
    parseBegin(p, result)
  of pxCommand: result = parseCommand(p)
  of pxCurlyDirLe, pxStarDirLe: 
    if isHandledDirective(p): result = parseDirective(p)
  of pxIf: result = parseIf(p)
  of pxWhile: result = parseWhile(p)
  of pxRepeat: result = parseRepeat(p)
  of pxCase: result = parseCase(p)
  of pxTry: result = parseTry(p)
  of pxProcedure, pxFunction: result = parseRoutine(p)
  of pxType: result = parseTypeSection(p)
  of pxConst: result = parseConstSection(p)
  of pxVar: result = parseVar(p)
  of pxFor: 
    result = parseFor(p)
    fixVarSection(p, result.sons[0])
  of pxRaise: result = parseRaise(p)
  of pxUses: result = parseUsesStmt(p)
  of pxProgram, pxUnit, pxLibrary: 
    # skip the pointless header
    while not (p.tok.xkind in {pxSemicolon, pxEof}): getTok(p)
    getTok(p)
  of pxInitialization: getTok(p) # just skip the token
  of pxImplementation: 
    p.section = seImplementation
    result = newNodeP(nkCommentStmt, p)
    result.comment = "# implementation"
    getTok(p)
  of pxInterface: 
    p.section = seInterface
    getTok(p)
  of pxComment: 
    result = newNodeP(nkCommentStmt, p)
    skipCom(p, result)
  of pxSemicolon: getTok(p)
  of pxSymbol: 
    if p.tok.ident.id == getIdent("break").id: 
      result = newNodeP(nkBreakStmt, p)
      getTok(p)
      skipCom(p, result)
      addSon(result, ast.emptyNode)
    elif p.tok.ident.id == getIdent("continue").id: 
      result = newNodeP(nkContinueStmt, p)
      getTok(p)
      skipCom(p, result)
      addSon(result, ast.emptyNode)
    elif p.tok.ident.id == getIdent("exit").id: 
      result = newNodeP(nkReturnStmt, p)
      getTok(p)
      skipCom(p, result)
      addSon(result, ast.emptyNode)
    else: 
      result = parseExprStmt(p)
  of pxDot: getTok(p) # BUGFIX for ``end.`` in main program
  else: result = parseExprStmt(p)
  opt(p, pxSemicolon)
  if result.kind != nkEmpty: skipCom(p, result)
  p.context = oldcontext

proc parseUnit(p: var TParser): PNode = 
  result = newNodeP(nkStmtList, p)
  getTok(p)                   # read first token
  while true: 
    case p.tok.xkind
    of pxEof, pxEnd: break 
    of pxBegin: parseBegin(p, result)
    of pxCurlyDirLe, pxStarDirLe: 
      if isHandledDirective(p): addSon(result, parseDirective(p))
      else: parMessage(p, errXNotAllowedHere, p.tok.ident.s)
    else: addSon(result, parseStmt(p))
  opt(p, pxEnd)
  opt(p, pxDot)
  if p.tok.xkind != pxEof: 
    addSon(result, parseStmt(p)) # comments after final 'end.'