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
|
#
#
# The Nim Compiler
# (c) Copyright 2015 Andreas Rumpf
#
# See the file "copying.txt", included in this
# distribution, for details about the copyright.
#
## This module does the semantic transformation of the fields* iterators.
# included from semstmts.nim
type
TFieldInstCtx = object # either 'tup[i]' or 'field' is valid
tupleType: PType # if != nil we're traversing a tuple
tupleIndex: int
field: PSym
replaceByFieldName: bool
c: PContext
proc instFieldLoopBody(c: TFieldInstCtx, n: PNode, forLoop: PNode): PNode =
if c.field != nil and isEmptyType(c.field.typ):
result = newNode(nkEmpty)
return
case n.kind
of nkEmpty..pred(nkIdent), succ(nkSym)..nkNilLit: result = copyNode(n)
of nkIdent, nkSym:
result = n
let ident = considerQuotedIdent(c.c, n)
if c.replaceByFieldName:
if ident.id == considerQuotedIdent(c.c, forLoop[0]).id:
let fieldName = if c.tupleType.isNil: c.field.name.s
elif c.tupleType.n.isNil: "Field" & $c.tupleIndex
else: c.tupleType.n[c.tupleIndex].sym.name.s
result = newStrNode(nkStrLit, fieldName)
return
# other fields:
for i in ord(c.replaceByFieldName)..<forLoop.len-2:
if ident.id == considerQuotedIdent(c.c, forLoop[i]).id:
var call = forLoop[^2]
var tupl = call[i+1-ord(c.replaceByFieldName)]
if c.field.isNil:
result = newNodeI(nkBracketExpr, n.info)
result.add(tupl)
result.add(newIntNode(nkIntLit, c.tupleIndex))
else:
result = newNodeI(nkDotExpr, n.info)
result.add(tupl)
result.add(newSymNode(c.field, n.info))
break
else:
if n.kind == nkContinueStmt:
localError(c.c.config, n.info,
"'continue' not supported in a 'fields' loop")
result = shallowCopy(n)
for i in 0..<n.len:
result[i] = instFieldLoopBody(c, n[i], forLoop)
type
TFieldsCtx = object
c: PContext
m: TMagic
proc semForObjectFields(c: TFieldsCtx, typ, forLoop, father: PNode) =
case typ.kind
of nkSym:
# either 'tup[i]' or 'field' is valid
var fc = TFieldInstCtx(
c: c.c,
field: typ.sym,
replaceByFieldName: c.m == mFieldPairs
)
openScope(c.c)
inc c.c.inUnrolledContext
let body = instFieldLoopBody(fc, lastSon(forLoop), forLoop)
father.add(semStmt(c.c, body, {}))
dec c.c.inUnrolledContext
closeScope(c.c)
of nkNilLit: discard
of nkRecCase:
let call = forLoop[^2]
if call.len > 2:
localError(c.c.config, forLoop.info,
"parallel 'fields' iterator does not work for 'case' objects")
return
# iterate over the selector:
semForObjectFields(c, typ[0], forLoop, father)
# we need to generate a case statement:
var caseStmt = newNodeI(nkCaseStmt, forLoop.info)
# generate selector:
var access = newNodeI(nkDotExpr, forLoop.info, 2)
access[0] = call[1]
access[1] = newSymNode(typ[0].sym, forLoop.info)
caseStmt.add(semExprWithType(c.c, access))
# copy the branches over, but replace the fields with the for loop body:
for i in 1..<typ.len:
var branch = copyTree(typ[i])
branch[^1] = newNodeI(nkStmtList, forLoop.info)
semForObjectFields(c, typ[i].lastSon, forLoop, branch[^1])
caseStmt.add(branch)
father.add(caseStmt)
of nkRecList:
for t in items(typ): semForObjectFields(c, t, forLoop, father)
else:
illFormedAstLocal(typ, c.c.config)
proc semForFields(c: PContext, n: PNode, m: TMagic): PNode =
# so that 'break' etc. work as expected, we produce
# a 'while true: stmt; break' loop ...
result = newNodeI(nkWhileStmt, n.info, 2)
var trueSymbol = systemModuleSym(c.graph, getIdent(c.cache, "true"))
if trueSymbol == nil:
localError(c.config, n.info, "system needs: 'true'")
trueSymbol = newSym(skUnknown, getIdent(c.cache, "true"), c.idgen, getCurrOwner(c), n.info)
trueSymbol.typ = getSysType(c.graph, n.info, tyBool)
result[0] = newSymNode(trueSymbol, n.info)
var stmts = newNodeI(nkStmtList, n.info)
result[1] = stmts
var call = n[^2]
if n.len-2 != call.len-1 + ord(m==mFieldPairs):
localError(c.config, n.info, errWrongNumberOfVariables)
return result
const skippedTypesForFields = abstractVar - {tyTypeDesc} + tyUserTypeClasses
var tupleTypeA = skipTypes(call[1].typ, skippedTypesForFields)
if tupleTypeA.kind notin {tyTuple, tyObject}:
localError(c.config, n.info, errGenerated, "no object or tuple type")
return result
for i in 1..<call.len:
let calli = call[i]
var tupleTypeB = skipTypes(calli.typ, skippedTypesForFields)
if not sameType(tupleTypeA, tupleTypeB):
typeMismatch(c.config, calli.info, tupleTypeA, tupleTypeB, calli)
inc(c.p.nestedLoopCounter)
let oldBreakInLoop = c.p.breakInLoop
c.p.breakInLoop = true
if tupleTypeA.kind == tyTuple:
var loopBody = n[^1]
for i in 0..<tupleTypeA.len:
openScope(c)
var fc = TFieldInstCtx(
tupleType: tupleTypeA,
tupleIndex: i,
c: c,
replaceByFieldName: m == mFieldPairs
)
var body = instFieldLoopBody(fc, loopBody, n)
inc c.inUnrolledContext
stmts.add(semStmt(c, body, {}))
dec c.inUnrolledContext
closeScope(c)
else:
var fc = TFieldsCtx(m: m, c: c)
var t = tupleTypeA
while t.kind == tyObject:
semForObjectFields(fc, t.n, n, stmts)
if t.baseClass == nil: break
t = skipTypes(t.baseClass, skipPtrs)
c.p.breakInLoop = oldBreakInLoop
dec(c.p.nestedLoopCounter)
# for TR macros this 'while true: ...; break' loop is pretty bad, so
# we avoid it now if we can:
if containsNode(stmts, {nkBreakStmt}):
var b = newNodeI(nkBreakStmt, n.info)
b.add(newNodeI(nkEmpty, n.info))
stmts.add(b)
else:
result = stmts
|