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Merge pull request #648 from cubbimew/travis-fixes
fix Travis CI issues caused by recent direct commits
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CppCoreGuidelines.md

Lines changed: 83 additions & 78 deletions
Original file line numberDiff line numberDiff line change
@@ -465,7 +465,7 @@ portability will be impacted.
465465
Using valid ISO C++ does not guarantee portability (let alone correctness).
466466
Avoid dependence on undefined behavior (e.g., [undefined order of evaluation](#Res-order))
467467
and be aware of constructs with implementation defined meaning (e.g., `sizeof(int)`).
468-
468+
469469
##### Note
470470

471471
There are environments where restrictions on use of standard C++ language or library features are necessary, e.g., to avoid dynamic memory allocation as required by aircraft control software standards.
@@ -585,7 +585,7 @@ You don't need to write error handlers for errors caught at compile time.
585585
cerr << "Int too small\n"
586586

587587
This example is easily simplified
588-
588+
589589
// Int is an alias used for integers
590590
static_assert(sizeof(Int) >= 4); // do: compile-time check
591591

@@ -594,12 +594,12 @@ This example is easily simplified
594594
void read(int* p, int n); // read max n integers into *p
595595

596596
int a[100];
597-
read(a,1000); // bad
597+
read(a, 1000); // bad
598598

599599
better
600600

601601
void read(span<int> r); // read into the range of integers r
602-
602+
603603
int a[100];
604604
read(a); // better: let the compiler figure out the number of elements
605605

@@ -988,7 +988,7 @@ Messy, low-level code breads more such code.
988988
if (count==sz)
989989
p = (int*) realloc(p,sizeof(int)*sz*2);
990990
// ...
991-
991+
992992
This is low-level, verbose, and error-prone.
993993
Insted, we could use `vector`:
994994

@@ -2687,7 +2687,7 @@ With C++11 we can write this, putting the results directly in existing local var
26872687

26882688
With C++17 we should be able to use "structured bindinds" to declare and initialize the multiple variables:
26892689

2690-
auto [iter,success] = myset.insert("Hello"); // C++17 structured binding
2690+
auto [iter, success] = myset.insert("Hello"); // C++17 structured binding
26912691
if (success) do_something_with(iter);
26922692

26932693
##### Exception
@@ -2699,7 +2699,7 @@ For example:
26992699

27002700
istream& operator>>(istream& is, string& s); // much like std::operator>>()
27012701

2702-
for (string s; cin>>s; ) {
2702+
for (string s; cin >> s; ) {
27032703
// do something with line
27042704
}
27052705

@@ -2712,11 +2712,11 @@ such as `string` and `vector`, that needs to do free store allocations.
27122712

27132713
To compare, if we passed out all values as return values, we would something like this:
27142714

2715-
pair<istream&,string> get_string(istream& is); // not recommended
2715+
pair<istream&, string> get_string(istream& is); // not recommended
27162716
{
27172717
string s;
2718-
cin>>s;
2719-
return {is,s};
2718+
cin >> s;
2719+
return {is, s};
27202720
}
27212721

27222722
for (auto p = get_string(cin); p.first; ) {
@@ -2768,24 +2768,23 @@ It complicates checking and tool support.
27682768

27692769
##### Example
27702770

2771-
void use(int* p, int nchar* s, int* q)
2771+
void use(int* p, int n, char* s, int* q)
27722772
{
2773-
p[n-1] = 666; // Bad: we don't know if p points to n elements; assume it does not or use span<int>
2774-
2775-
cout << s; // Bad: we don't know if that s points to a zero-terminated array of char; // assume it does not or use zstring
2776-
2777-
delete q; // Bad: we don't know if *q is allocated on the free store; assume it does not or use owner
2773+
p[n-1] = 666; // Bad: we don't know if p points to n elements;
2774+
// assume it does not or use span<int>
2775+
cout << s; // Bad: we don't know if that s points to a zero-terminated array of char;
2776+
// assume it does not or use zstring
2777+
delete q; // Bad: we don't know if *q is allocated on the free store;
2778+
//assume it does not or use owner
27782779
}
27792780

27802781
better
27812782

27822783
void use2(span<int> p, zstring s, owner<int*> q)
27832784
{
2784-
p[p.size()-1] = 666; // OK, a range error can be caught
2785-
2786-
cout << s; // OK
2787-
2788-
delete q; // OK
2785+
p[p.size()-1] = 666; // OK, a range error can be caught
2786+
cout << s; // OK
2787+
delete q; // OK
27892788
}
27902789

27912790
##### Note
@@ -6150,16 +6149,16 @@ This Shape hierarchy can be rewritten using interface inheritance:
61506149

61516150
class Shape { // pure interface
61526151
public:
6153-
virtual Point center() const =0;
6154-
virtual Color color() const =0;
6152+
virtual Point center() const = 0;
6153+
virtual Color color() const = 0;
61556154

6156-
virtual void rotate(int) =0;
6157-
virtual void move(Point p) =0;
6155+
virtual void rotate(int) = 0;
6156+
virtual void move(Point p) = 0;
61586157

6159-
virtual void redraw() =0;
6158+
virtual void redraw() = 0;
61606159

61616160
// ...
6162-
};
6161+
};
61636162

61646163
Note that a pure interface rarely have constructors: there is nothing to construct.
61656164

@@ -6190,13 +6189,13 @@ First we devise a hierarchy of interface classes:
61906189

61916190
class Shape { // pure interface
61926191
public:
6193-
virtual Point center() const =0;
6194-
virtual Color color() const =0;
6192+
virtual Point center() const = 0;
6193+
virtual Color color() const = 0;
61956194

6196-
virtual void rotate(int) =0;
6197-
virtual void move(Point p) =0;
6195+
virtual void rotate(int) = 0;
6196+
virtual void move(Point p) = 0;
61986197

6199-
virtual void redraw() =0;
6198+
virtual void redraw() = 0;
62006199

62016200
// ...
62026201
};
@@ -6258,7 +6257,7 @@ Since each implementation derived from its inteface as well as its implementatio
62586257
Smiley -> Circle -> Shape
62596258
^ ^ ^
62606259
| | |
6261-
Impl::Smiley -> Impl::Circle -> Impl::Shape
6260+
Impl::Smiley -> Impl::Circle -> Impl::Shape
62626261

62636262
As mentioned, this is just one way to construct a dual hierarchy.
62646263

@@ -7479,9 +7478,12 @@ The default is the easiest to read and write.
74797478

74807479
##### Example
74817480

7482-
enum class Direction : char { n, s, e, w, ne, nw, se, sw }; // underlying type saves space
7481+
enum class Direction : char { n, s, e, w,
7482+
ne, nw, se, sw }; // underlying type saves space
74837483

7484-
enum class Webcolor : int { red = 0xFF0000, green = 0x00FF00, blue = 0x0000FF }; // underlying type is redundant
7484+
enum class Webcolor : int { red = 0xFF0000,
7485+
green = 0x00FF00,
7486+
blue = 0x0000FF }; // underlying type is redundant
74857487

74867488
##### Note
74877489

@@ -7512,9 +7514,10 @@ The default gives a consequtive set of values that is good for `switch`-statemen
75127514
##### Example
75137515

75147516
enum class Col1 { red, yellow, blue };
7515-
enum class Col2 { red=1, red=2, blue=2 }; // typo
7516-
enum class Month { jan=1, feb, mar, apr, mar, jun, jul, august, sep, oct, nov, dec }; // starting with 1 is conventional
7517-
enum class Base_flag { dec=1, oct=dec<<1, hex=dec<<2 }; // set of bits
7517+
enum class Col2 { red = 1, red = 2, blue = 2 }; // typo
7518+
enum class Month { jan = 1, feb, mar, apr, mar, jun,
7519+
jul, august, sep, oct, nov, dec }; // starting with 1 is conventional
7520+
enum class Base_flag { dec = 1, oct = dec << 1, hex = dec << 2 }; // set of bits
75187521

75197522
Specifying values are neccessary to match conventional values (e.g., `Month`)
75207523
and where consecutive values are undesirable (e.g., to get separate bits as in `Base_flag`).
@@ -9416,29 +9419,29 @@ Requires messy cast-and-macro-laden code to get working right.
94169419

94179420
void error(int severity ...) // ``severity'' followed by a zero-terminated list of char*s; write the C-style strings to cerr
94189421
{
9419-
va_list ap; // a magic type for holding arguments
9420-
va_start(ap,severity); // arg startup: "severity" is the first argument of error()
9422+
va_list ap; // a magic type for holding arguments
9423+
va_start(ap, severity); // arg startup: "severity" is the first argument of error()
94219424

9422-
for (;;) {
9423-
char* p = va_arg(ap,char*); // treat the next var as a char*; no checking: a cast in disguise
9424-
if (p == nullptr) break;
9425-
cerr << p << ' ';
9426-
}
9425+
for (;;) {
9426+
char* p = va_arg(ap, char*); // treat the next var as a char*; no checking: a cast in disguise
9427+
if (p == nullptr) break;
9428+
cerr << p << ' ';
9429+
}
94279430

9428-
va_end(ap); // arg cleanup (don't forget this)
9431+
va_end(ap); // arg cleanup (don't forget this)
94299432

9430-
cerr << '\en';
9431-
if (severity) exit(severity);
9433+
cerr << '\n';
9434+
if (severity) exit(severity);
94329435
}
94339436

94349437
void use()
94359438
{
9436-
error(7,"this","is","an","error", nullptr);
9439+
error(7, "this", "is", "an", "error", nullptr);
94379440
error(7); // crash
9438-
error(7,"this","is","an","error"); // crash
9441+
error(7, "this", "is", "an", "error"); // crash
94399442
const char* is = "is";
94409443
string an = "an";
9441-
error(7,"this","is,an,"error"); // crash
9444+
error(7, "this", "is", an, "error"); // crash
94429445
}
94439446

94449447
**Alternative**: Overloading. Templates. Variadic templates.
@@ -13511,10 +13514,10 @@ To say "`T` is `Sortable`":
1351113514
// requires Sortable<T> // of type T which is the name of a type
1351213515
void sort(T&); // that is Sortable"
1351313516

13514-
template<Sortable T> // Better (assuming language support for concepts): "The parameter is of type T
13517+
template<Sortable T> // Better (assuming support for concepts): "The parameter is of type T
1351513518
void sort(T&); // which is Sortable"
1351613519

13517-
void sort(Sortable&); // Best (assuming language support for concepts): "The parameter is Sortable"
13520+
void sort(Sortable&); // Best (assuming support for concepts): "The parameter is Sortable"
1351813521

1351913522
The shorter versions better match the way we speak. Note that many templates don't need to use the `template` keyword.
1352013523

@@ -13743,9 +13746,9 @@ An incomplete set of constraints can still be very useful:
1374313746

1374413747
// balancer for a generic binary tree
1374513748
template<typename Node> concept bool Balancer = requires(Node* p) {
13746-
add_fixup(p);
13747-
touch(p);
13748-
detach(p);
13749+
add_fixup(p);
13750+
touch(p);
13751+
detach(p);
1374913752
}
1375013753

1375113754
So a `Balancer` must supply at least thee operations on a tree `Node`,
@@ -13799,7 +13802,7 @@ Two concepts requiring the same syntax but having different semantics leads to a
1379913802
template<typename I> // iterator providing random access to contiguous data
1380013803
concept bool Contiguous_iter =
1380113804
RA_iter<I> && is_contiguous<I>::value; // using is_contiguous trait
13802-
13805+
1380313806
The programmer (in a library) must define `is_contiguous` (a trait) appropriately.
1380413807

1380513808
Wrapping a tag class into a concept leads to a simpler expression of this idea:
@@ -13864,11 +13867,11 @@ The compiler will select the overload and emit an appropriate error.
1386413867
Complementary constraints are unfortunately common in `enable_if` code:
1386513868

1386613869
template<typename T>
13867-
enable_if<!C<T>,void> // bad
13870+
enable_if<!C<T>, void> // bad
1386813871
f();
1386913872

1387013873
template<typename T>
13871-
enable_if<C<T>,void>
13874+
enable_if<C<T>, void>
1387213875
f();
1387313876

1387413877

@@ -14009,7 +14012,7 @@ we delay checking until instantiation time.
1400914012
We consider this a worthwhile tradeoff.
1401014013

1401114014
Note that using non-local, non-dependent names (such as `debug` and `cerr`) also introduce context dependencies that may lead to "mysterious" errors.
14012-
14015+
1401314016
##### Note
1401414017

1401514018
It can be hard to decide which properties of a type is essential and which are not.
@@ -14277,17 +14280,18 @@ Eases tool creation.
1427714280
template<typename C>
1427814281
void sort(C& c)
1427914282
{
14280-
std::sort(begin(c),end(c)); // necessary and useful dependency
14283+
std::sort(begin(c), end(c)); // necessary and useful dependency
1428114284
}
1428214285

1428314286
template<typename Iter>
1428414287
Iter algo(Iter first, Iter last) {
14285-
for (; first!=last; ++first) {
14288+
for (; first != last; ++first) {
1428614289
auto x = sqrt(*first); // potentially surprising dependency: which sqrt()?
14287-
helper(first,x); // potentially surprising dependency: heper is chosen based on first and x
14290+
helper(first, x); // potentially surprising dependency:
14291+
// helper is chosen based on first and x
1428814292
TT var = 7; // potentially surprising dependency: which TT?
1428914293
}
14290-
}
14294+
}
1429114295

1429214296
##### Note
1429314297

@@ -14448,10 +14452,10 @@ This is a simplified version of `std::copy` (ignoring the possibility of non-con
1444814452

1444914453
template<class T> struct copy_trait { using tag = non_pod_tag; }; // T is not "plain old data"
1445014454

14451-
template<> struct copy_trait<int> { using tab = pod_tag; }; // int is "plain old data"
14455+
template<> struct copy_trait<int> { using tab = pod_tag; }; // int is "plain old data"
1445214456

1445314457
template<class Iter>
14454-
Out copy_helper(Iter first, Iter last, Iter out, pog_tag)
14458+
Out copy_helper(Iter first, Iter last, Iter out, pod_tag)
1445514459
{
1445614460
// use memmove
1445714461
}
@@ -14465,13 +14469,13 @@ This is a simplified version of `std::copy` (ignoring the possibility of non-con
1446514469
template<class Itert>
1446614470
Out copy(Iter first, Iter last, Iter out)
1446714471
{
14468-
return copy_helper(first,last,out, typename copy_trait<Iter>::tag{})
14472+
return copy_helper(first, last, out, typename copy_trait<Iter>::tag{})
1446914473
}
1447014474

1447114475
void use(vector<int>& vi, vector<int>& vi2, vector<string>& vs, vector<string>& vs2)
1447214476
{
14473-
copy(vi.begin(),vi.end(), vi2.begin()); // uses memmove
14474-
copy(vs.begin(),vs.end(), vs2.begin()); // uses a loop calling copy constructors
14477+
copy(vi.begin(), vi.end(), vi2.begin()); // uses memmove
14478+
copy(vs.begin(), vs.end(), vs2.begin()); // uses a loop calling copy constructors
1447514479
}
1447614480

1447714481
This is a general and powerful technique for compile-time algorithm selection.
@@ -14528,7 +14532,7 @@ When `concept`s become widely available such alternatives can be distinguished d
1452814532
auto x = T(u); // construction or cast?
1452914533
}
1453014534

14531-
f(1,"asdf); // bad: cast from const char* to int
14535+
f(1, "asdf"); // bad: cast from const char* to int
1453214536

1453314537
##### Enforcement
1453414538

@@ -14563,10 +14567,10 @@ There are three major ways to let calling code customize a template.
1456314567

1456414568
template<class T>
1456514569
void test3(T t)
14566-
// Invoke a "trait"
14567-
14568-
{
14569-
test_traits<T>::f(t); // require customizing test_traits<> to get non-default functions/types
14570+
// Invoke a "trait"
14571+
{
14572+
test_traits<T>::f(t); // require customizing test_traits<>
14573+
// to get non-default functions/types
1457014574
}
1457114575

1457214576
A trait is usually a type alias to compute a type,
@@ -14993,15 +14997,16 @@ Documentation, readability, opportunity for reuse.
1499314997

1499414998
bool same(const Rec& a, const Rec& b)
1499514999
{
14996-
return a.id==b.id;
15000+
return a.id == b.id;
1499715001
}
1499815002

1499915003
vector<Rec*> find_id(const string& name); // find all records for "name"
1500015004

15001-
auto x = find_if(vr.begin(),vr.end(),
15005+
auto x = find_if(vr.begin(), vr.end(),
1500215006
[&](Rec& r) {
15003-
if (r.name.size()!=n.size()) return false; // name to compare to is in n
15004-
for (int i=0; i<r.name.size(); ++i) if (tolower(r.name[i])!=tolower(n[i])) return false;
15007+
if (r.name.size() != n.size()) return false; // name to compare to is in n
15008+
for (int i=0; i < r.name.size(); ++i)
15009+
if (tolower(r.name[i]) != tolower(n[i])) return false;
1500515010
return true;
1500615011
}
1500715012
);

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