CharT< T > Struct Template Reference

#include <evo/type.h>

Inheritance diagram for CharT< T >:

Detailed Description

template<class T>
struct evo::CharT< T >

Nullable primitive character base type.

Template Parameters

T	Character type (char)

Character types:

• Char

Examples:

• Assigned like a char:

  Char val('A');          // Set to 'A'
  val = 'b';              // Set to 'b'

• Can hold null value:

  Char val;               // Null by default
  val = 'B';              // Set to 'B', no longer null
  val.set();              // Set to null

• Evaluate as bool to check non-null and non-zero:

  Char val;               // Null by default
  if (val) {              // false
  }
  if (!val) {             // true
  }
  val = '\0';
  if (val) {              // false
  }
  val = 'A';
  if (val) {              // true
  }

• Use denull() to clear null flag and update value via reference – useful for decrement/increment:

  Char val;               // Null by default
  ++val.denull();         // Remove null flag (value is 0) and increment so value is now 1

• Dereference to get raw value:

  Char val;               // Null by default
  if (*val == 'A') {      // Dereference for raw value -- false: 0 when null
  }

• Comparison operator overloads:

  Char val;               // Null by default, with raw value 0
  if (*val == '\0') {     // true: raw value is 0
  }
  if (val == '\0') {      // false: null is not 0
  }
  if (val < '\0') {       // true: null is less than any value
  }
  if (*val < '\0') {      // false: raw value is 0
  }

• Some traits and helpers

  int num_bits = Char::BITS;                   // get number of bits per char (8 bits)
  if (Char::category('1') > Char::cALPHANUM) { // check character category (alpha-numeric) -- true
  }
  if (Char::isupper('A') {                     // check if upper-case character (static helper) -- true
  }

Public Types
enum	Category {   cNONE =0, cSPACE, cSYMBOL, cALPHANUM,   cDIGIT, cALPHA, cALPHA_U, cALPHA_L }
	Character category. More...
enum	Digit {   dNONE =0, dBASE36, dHEX, dDECIMAL,   dOCTAL }
	Character digit type. More...
typedef void	EvoNullableType
	Identify as nullable type. More...
typedef CharT< T >	This
	This non-POD type More...
typedef T	Type
	Wrapped POD type. More...

Public Member Functions
	CharT ()
	Constructor. More...
	CharT (const CharT< T > &val)
	Copy constructor. More...
	CharT (T val)
	Constructor. More...
int	compare (const Nullable< T > &val) const
	Comparison. More...
int	compare (T val) const
	Comparison. More...
T &	denull ()
	Clears null flag and returns value reference. More...
bool	null () const
	Get whether null. More...
	operator SafeBoolType () const
	Safe (explicit) evaluation as bool type. More...
bool	operator! () const
	Negation operator returns whether null or 0. More...
bool	operator!= (const Nullable< T > &val) const
	Inequality operator. More...
bool	operator!= (T val) const
	Inequality operator. More...
const T &	operator* () const
	Dereference for explicit conversion to underlying type (const). More...
T &	operator* ()
	Dereference for explicit conversion to underlying type. More...
bool	operator< (const Nullable< T > &val) const
	Less than operator. More...
bool	operator< (T val) const
	Less than operator. More...
bool	operator<= (const Nullable< T > &val) const
	Less than or equal operator. More...
bool	operator<= (T val) const
	Less than or equal operator. More...
CharT< T > &	operator= (const CharT< char > &val)
	Assignment operator. More...
CharT< T > &	operator= (char val)
	Assignment operator. More...
CharT< T > &	operator= (ValNull)
	Assignment operator to set as null by passing vNULL. More...
bool	operator== (const Nullable< T > &val) const
	Equality operator. More...
bool	operator== (T val) const
	Equality operator. More...
bool	operator> (const Nullable< T > &val) const
	Greater than operator. More...
bool	operator> (T val) const
	Greater than operator. More...
bool	operator>= (const Nullable< T > &val) const
	Greater than or equal operator. More...
bool	operator>= (T val) const
	Greater than or equal operator. More...
Nullable< T > &	set ()
	Set as null. More...
Nullable< T > &	set (const Nullable< T > &src)
	Set as copy of given value. More...
Nullable< T > &	set (T src)
	Set as given value. More...
bool	valid () const
	Get whether valid (not null). More...
const T &	value () const
	Get underlying value (const). More...
T &	value ()
	Get underlying value. More...

Static Public Attributes
static const int	BITS = BYTES * CHAR_BIT
	Type size in bits (8) More...
static const int	BYTES = sizeof(T)
	Type size in bytes, usually 1. More...

Member Typedef Documentation

EvoNullableType

typedef void EvoNullableType

inherited

Identify as nullable type.

This

typedef CharT<T> This

This non-POD type

Type

typedef T Type

Wrapped POD type.

Member Enumeration Documentation

Category

enum Category

Character category.

• Overlapping categories (ex: alphanumeric) can be checked with greater-than (>) comparison:

  Char::Category cat = Char::category(ch);
  bool space     = (cat == Char::cSPACE);     // Whitespace (space, tab)
  bool symbol    = (cat == Char::cSYMBOL);    // Symbols (comma, precent, dollar, etc)
  bool digit     = (cat == Char::cDIGIT);     // Decimal digit (0-9)
  bool uppercase = (cat == Char::cALPHA_U);   // Alphabet uppercase (A-Z)
  bool lowercase = (cat == Char::cALPHA_L);   // Alphabet lowercase (a-z)
  bool alphanum  = (cat > Char::cALPHANUM);   // Alphanumeric (0-9, A-Z, a-z)
  bool alpha     = (cat > Char::cALPHA);      // Alphabet (A-Z, a-z)
  bool printable = (cat > Char::cNONE);       // Any printable character
  bool visible   = (cat > Char::cSPACE);      // Any visible character (printable and not whitespace)

Enumerator
cNONE	Non printable char.
cSPACE	Whitespace (space, tab)
cSYMBOL	Symbol character (printable but not alphanumeric)
cALPHANUM	Alpha-numeric – categories greater than this are alphanumeric.
cDIGIT	Decimal digit (0-9)
cALPHA	Alphabet – categories greater than this are alphabetic.
cALPHA_U	Alphabet uppercase (A-Z)
cALPHA_L	Alphabet lowercase (a-z)

Digit

enum Digit

Character digit type.

• Digit types overlap so check with greater-than-or-equal (>=) comparison:

  Char::Digit dig = Char::digit(ch);
  bool b36 = (dig >= Char::dBASE36);  // base 36 digit (0-9, A-Z)
  bool hex = (dig >= Char::dHEX);     // hex digit (0-9, A-F)
  bool dec = (dig >= Char::dDECIMAL); // decimal digit (0-9)
  bool oct = (dig >= Char::dOCTAL);   // octal digit (0-7)
  bool err = (dig == Char::dHEX);     // error: must use operator >= here

Enumerator
dNONE	Not a digit.
dBASE36	Base 36 character.
dHEX	Hexadecimal character.
dDECIMAL	Decimal character.
dOCTAL	Octal character.

Constructor & Destructor Documentation

CharT() [1/3]

CharT ( )

inline

Constructor.

CharT() [2/3]

CharT ( const CharT< T > &  val )

inline

Copy constructor.

Parameters

val	Value to copy

CharT() [3/3]

CharT ( T  val )

inline

Constructor.

Parameters

val	Value to set

Member Function Documentation

compare() [1/2]

int compare ( const Nullable< T > &  val ) const

inlineinherited

Comparison.

Parameters

val	Value to compare to

Returns

Result (<0 if this is less, 0 if equal, >0 if this is greater)

compare() [2/2]

int compare ( T  val ) const

inlineinherited

Comparison.

• If null, the result is always -1 as null compares as less than any non-null value

Parameters

val	Value to compare to

Returns

Result (<0 if this is less, 0 if equal, >0 if this is greater)

denull()

T& denull ( )

inlineinherited

Clears null flag and returns value reference.

• Value is unchanged, POD types default to 0 when null
• Useful for updating the underlying value by reference
• Note: Nullable<bool> template specialization returns by value instead of reference

Returns

Whether valid

null()

bool null ( ) const

inlineinherited

Get whether null.

Returns

Whether null

operator SafeBoolType()

operator SafeBoolType ( ) const

inlineinherited

Safe (explicit) evaluation as bool type.

• This is called when object is directly evaluated as a bool, and is equivalent to: !operator!()
• See SafeBool

operator!()

bool operator! ( ) const

inlineinherited

Negation operator returns whether null or 0.

Returns

Whether null or 0

operator!=() [1/2]

bool operator!= ( const Nullable< T > &  val ) const

inlineinherited

Inequality operator.

Parameters

val	Value to compare to

Returns

Whether inequal

operator!=() [2/2]

bool operator!= ( T  val ) const

inlineinherited

Inequality operator.

• If null, the result is always true as null is not equal to any non-null value

Parameters

val	Value to compare to

Returns

Whether inequal, true if null

operator*() [1/2]

const T& operator* ( ) const

inlineinherited

Dereference for explicit conversion to underlying type (const).

Alternative to value().

Returns

Underlying type value

operator*() [2/2]

T& operator* ( )

inlineinherited

Dereference for explicit conversion to underlying type.

Alternative to value().

Returns

Underlying type value

operator<() [1/2]

bool operator< ( const Nullable< T > &  val ) const

inlineinherited

Less than operator.

• If null, null is less than any non-null value

Parameters

val	Value to compare to

Returns

Whether less than val

operator<() [2/2]

bool operator< ( T  val ) const

inlineinherited

Less than operator.

• If null, null is less than any non-null value

Parameters

val	Value to compare to

Returns

Whether less than val

operator<=() [1/2]

bool operator<= ( const Nullable< T > &  val ) const

inlineinherited

Less than or equal operator.

• If null, null is less than or equal to any value

Parameters

val	Value to compare to

Returns

Whether less than or equal to val, true if null

operator<=() [2/2]

bool operator<= ( T  val ) const

inlineinherited

Less than or equal operator.

• If null, null is less than or equal to any value

Parameters

val	Value to compare to

Returns

Whether less than or equal to val, true if null

operator=() [1/3]

CharT<T>& operator= ( const CharT< char > &  val )

inline

Assignment operator.

Parameters

val	Value to copy

Returns

This

operator=() [2/3]

CharT<T>& operator= ( char  val )

inline

Assignment operator.

Parameters

val	Value to set

Returns

This

operator=() [3/3]

CharT<T>& operator= ( ValNull  )

inline

Assignment operator to set as null by passing vNULL.

Returns

This

operator==() [1/2]

bool operator== ( const Nullable< T > &  val ) const

inlineinherited

Equality operator.

Parameters

val	Value to compare to

Returns

Whether equal

operator==() [2/2]

bool operator== ( T  val ) const

inlineinherited

Equality operator.

• If null, the result is always false as null is not equal to any non-null value

Parameters

val	Value to compare to

Returns

Whether equal, false if null

operator>() [1/2]

bool operator> ( const Nullable< T > &  val ) const

inlineinherited

Greater than operator.

• If null, null is not greater than any non-null value

Parameters

val	Value to compare to

Returns

Whether greater than val, false if null

operator>() [2/2]

bool operator> ( T  val ) const

inlineinherited

Greater than operator.

• If null, null is not greater than any non-null value

Parameters

val	Value to compare to

Returns

Whether greater than val, false if null

operator>=() [1/2]

bool operator>= ( const Nullable< T > &  val ) const

inlineinherited

Greater than or equal operator.

• If null, null is not greater than any non-null value

Parameters

val	Value to compare to

Returns

Whether greater than or equal to val

operator>=() [2/2]

bool operator>= ( T  val ) const

inlineinherited

Greater than or equal operator.

• If null, null is not greater than any non-null value

Parameters

val	Value to compare to

Returns

Whether greater than or equal to val

set() [1/3]

Nullable<T>& set ( )

inlineinherited

Set as null.

Returns

This

set() [2/3]

Nullable<T>& set ( const Nullable< T > &  src )

inlineinherited

Set as copy of given value.

Parameters

src	Source to copy

Returns

This

set() [3/3]

Nullable<T>& set ( T  src )

inlineinherited

Set as given value.

Parameters

src	Source to set

Returns

This

valid()

bool valid ( ) const

inlineinherited

Get whether valid (not null).

Returns

Whether valid

value() [1/2]

const T& value ( ) const

inlineinherited

Get underlying value (const).

Alternative to operator*().

Returns

Whether valid

value() [2/2]

T& value ( )

inlineinherited

Get underlying value.

Alternative to operator*().

Returns

Whether valid

Member Data Documentation

BITS

const int BITS = BYTES * CHAR_BIT

static

Type size in bits (8)

BYTES

const int BYTES = sizeof(T)

static

Type size in bytes, usually 1.

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The documentation for this struct was generated from the following file:

• evo/type.h