C99的指定初始化转化为C89？用(a|e)?bnf实现吧，写个玩玩

用了自己实现的ebnf小库，没有实现捕获组，被迫用lambda捕获了若干临时变量。

熟悉bnf的，把它翻到自己熟悉的工具上，应该不困难。

struct MemberInfo

{

string type;

string name;

deque<int> arrSizes;

};

struct InitValue

{

string value;

vector<InitValue> sub;

string name;

// TYPE type;

InitValue(const vector<InitValue> & s, const string & n) : sub(s), name(n){}

InitValue(const string & v, const string & n) : value(v), name(n){}

string str() const

{

return !value.empty() ? value :

"{" + join(adaptors::transform(sub, [](const InitValue & v)

{

return v.str();

}), ", ") + "}"

;

}

void Set(deque<int> offsets, const string & v)

{

int offset = offsets.front();

offsets.pop_front();

if (offsets.empty())

{

assert(sub[offset].sub.size() == 0);

sub[offset].value = v;

}

else

{

assert(value.empty());

sub[offset].Set(offsets, v);

}

}

int FindOffset(deque<int> offsets, const string & n) const

{

if (offsets.size() != 1)

{

int offset = offsets.front();

offsets.pop_front();

return sub[offset].FindOffset(offsets, n);

}

for (int i = 0; i < sub.size(); ++i)

{

if (sub[i].name == n)

{

return i;

}

}

}

};

InitValue MakeArrsInitValue(InitValue curInitValue, const deque<int> & Sizes)

{

for (auto iter = Sizes.rbegin(); iter != Sizes.rend(); ++iter)

{

curInitValue = {vector<InitValue>(*iter, curInitValue), ""};

}

return curInitValue;

}

InitValue StructInitValue(map<string, vector<MemberInfo> > & structInfo, vector<MemberInfo> & memberInfos, const string & memberName)

{

return InitValue(copy_range<vector<InitValue> >(

adaptors::transform(memberInfos, [&structInfo](const MemberInfo & info)

{

auto initValue = (structInfo.count(info.type) == 0) ? InitValue("0", info.name) :

StructInitValue(structInfo, structInfo[info.type], info.name);

return MakeArrsInitValue(initValue, info.arrSizes);

})), memberName);

}

//注意，因为左递归的根因，不可以写成 E -> E T | T；必须是 E -> T*；或者E -> T E | T

// T*理解简单，但是对于数组，求值顺序是从左到右，不符合数组的语义，还需要自己做运算倒置。

// T E | T，T的解析恰好很完美，但是E还是从左到右的。把自己绕进去了。

bool expandC99(const string & in, string & out)

{

vector<string> tmpCurStructName;

static map<string, vector<MemberInfo> > structInfo;



boost::function<void (string)> popCurStructName = [&tmpCurStructName](const string &)

{

tmpCurStructName.pop_back();

};

boost::function<void (string)> popCurStructNameAndRecordTypeName = [&tmpCurStructName, &structInfo](const string &)

{

string TypeName = tmpCurStructName.back();

tmpCurStructName.pop_back();

structInfo[tmpCurStructName.back()].push_back({TypeName, ""});

};

deque<int> tmpArrSizes;

auto arrSize = Words([&tmpArrSizes](const string & s)

{

tmpArrSizes.push_back(lexical_cast<int>(s));

});

SeqParser arr = Seq(AnySpaces, Str("["), AnySpaces, arrSize, AnySpaces, Str("]"));

SeqParser Struct;

auto memberType = Words([&tmpCurStructName, &structInfo](const string & s){structInfo[tmpCurStructName.back()].push_back({s, ""});});

auto memberName = Words([&tmpCurStructName, &structInfo](const string & s){structInfo[tmpCurStructName.back()].back().name = s;});

auto memberArrs = Keep(Any(arr, [&tmpCurStructName, &structInfo, &tmpArrSizes](const string & s)

{

structInfo[tmpCurStructName.back()].back().arrSizes = tmpArrSizes;

tmpArrSizes.clear();

}));

SeqParser member = Seq(AnySpaces,

Or(

Seq(Ref(Struct, popCurStructNameAndRecordTypeName), AnySpaces, memberName, memberArrs),

Seq(memberType, Spaces, memberName, memberArrs)

),

AnySpaces, Str(";"));

Struct =

Seq(Keep(Seq(

Str("struct"), Spaces,

Words([&tmpCurStructName](const string & s){tmpCurStructName.push_back(s);}),

AnySpaces, Str("{"),

More(member),

AnySpaces, Str("}")))

);



InitValue initValue = {"Not Init Exp!", ""};



boost::function<void (string)> popCurStructNameAndMakeStructValue = [&tmpCurStructName, &structInfo, &initValue](const string & s)

{

initValue = StructInitValue(structInfo, structInfo[tmpCurStructName.back()], s);

tmpCurStructName.pop_back();

};



auto typeName = Words([&structInfo, &initValue](const string & s)

{

initValue = (structInfo.count(s) == 0) ? /*数组需要*/ InitValue("0", "") :

StructInitValue(structInfo, structInfo[s], "");

});

auto varArrs = Keep(Any(arr, [&initValue, &tmpArrSizes](const string & s)

{

initValue = MakeArrsInitValue(initValue, tmpArrSizes);

}));



deque<int> tmpInitOffsets;

SeqParser inits;

auto noneInit = Stub([](const string & s){cout << "noneInit" << endl;});

auto valueInit = Words([&initValue, &tmpInitOffsets](const string & s){initValue.Set(tmpInitOffsets, s); ++tmpInitOffsets.back();});

auto baseInit = Or(valueInit, Ref(inits));

auto arrDesignator = Seq(Str("["), AnySpaces, Words([&tmpInitOffsets](const string & s){tmpInitOffsets.back() = lexical_cast<int>(s);}), AnySpaces, Str("]"));

auto structDesignator = Seq(Str("."), AnySpaces, Words([&initValue, &tmpInitOffsets](const string & s){tmpInitOffsets.back() = initValue.FindOffset(tmpInitOffsets, s);}));

int tmpMultiDesignator = 0;

vector<int> tmpMultiDesignators;

auto multiDesignatorStub = Stub([&tmpInitOffsets, &tmpMultiDesignator](const string &)

{

tmpInitOffsets.push_back(0); ++tmpMultiDesignator;

});

auto designatedInit = Seq(Or(arrDesignator, structDesignator),

Any(Seq(multiDesignatorStub, Or(arrDesignator, structDesignator)),

[&tmpMultiDesignator, &tmpMultiDesignators](const string &)

{

tmpMultiDesignators.push_back(tmpMultiDesignator);

tmpMultiDesignator = 0;

}),

AnySpaces, Str("="), AnySpaces, baseInit,

[&tmpInitOffsets, &tmpMultiDesignators](const string &)

{

tmpInitOffsets.resize(tmpInitOffsets.size() - tmpMultiDesignators.back());

tmpMultiDesignators.pop_back();

});

auto oneInit = Or(valueInit,

Ref(inits, [&tmpInitOffsets](const string & s){++tmpInitOffsets.back();}),

designatedInit);

auto moreInit = Seq(oneInit, Any(Seq(AnySpaces, Str(","), AnySpaces, oneInit)), AnySpaces, Optional(Str(",")));

inits = Seq(Str("{", [&tmpInitOffsets](const string &){tmpInitOffsets.push_back(0);}), AnySpaces,

Or(noneInit, moreInit), AnySpaces,

Str("}", [&tmpInitOffsets](const string &){tmpInitOffsets.pop_back();}));

auto defineTypedVar = Seq(typeName, Spaces, Words(), varArrs, AnySpaces, Str("="), AnySpaces, inits, AnySpaces, Str(";"));

auto defineStruct = Seq(Struct, AnySpaces, Str(";", popCurStructName));

auto defineStructVar = Seq(Struct, AnySpaces, Words(popCurStructNameAndMakeStructValue), varArrs, AnySpaces, Str("="), AnySpaces, inits, AnySpaces, Str(";"));

auto Exp = Or(defineTypedVar, defineStruct, defineStructVar);

bool r = Exp.Match(in);

cout << initValue.str() << endl;

return r;

}

BOOST_AUTO_TEST_CASE(TestStruct)

{

string out;

BOOST_CHECK_EQUAL(expandC99("struct A {int a ; int b ; int c ;} ;", out), true);

BOOST_CHECK_EQUAL(expandC99("struct B {int a ; int b [2] ; int c ;} a = {};", out), true);

BOOST_CHECK_EQUAL(expandC99("struct X {A a ; int b ; int c ;} a = {{1}, 3};", out), true);

BOOST_CHECK_EQUAL(expandC99("struct Y {int a ; struct XX {int i;} b ; int c ;} b = {.c = 3};", out), true);

BOOST_CHECK_EQUAL(expandC99("int a[3][2] = {{1, 2}, {3, 4}, [2][1] = 6};", out), true);

BOOST_CHECK_EQUAL(expandC99("X a[3][2] = {[1][0].a.b = 2};", out), true);

BOOST_CHECK_EQUAL(expandC99("X a[3][2] = {[1][0].a = {.b = 2}, [2][0].a.b = 3};", out), true);

}