...one of the most highly
regarded and expertly designed C++ library projects in the
world.
— Herb Sutter and Andrei
Alexandrescu, C++
Coding Standards
The int_parser
can parse
signed integers of arbitrary length and size. This is almost the same
as the uint_parser
. The
only difference is the additional task of parsing the '+'
or '-'
sign preceding the number.
The class interface is the same as that of the uint_parser
.
The int_parser
parser
can be used to parse ordinary primitive C/C++ integers or even user defined
scalars such as bigints (unlimited precision integers) as long as the
type follows certain expression requirements (documented below).
// forwards to <boost/spirit/home/qi/numeric/int.hpp> #include <boost/spirit/include/qi_int.hpp>
Also, see Include Structure.
Name |
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|
|
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Important | |
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template < typename T , unsigned Radix , unsigned MinDigits , int MaxDigits> struct int_parser;
Parameter |
Description |
Default |
---|---|---|
|
The numeric base type of the numeric parser. |
none |
|
The radix base. This can be either 2: binary, 8: octal, 10: decimal and 16: hexadecimal. |
10 |
|
The minimum number of digits allowable. |
1 |
|
The maximum number of digits allowable. If this is -1, then the maximum limit becomes unbounded. |
-1 |
Notation
NP
An instance of int_parser
(type).
n
An object of T
, the
numeric base type.
Semantics of an expression is defined only where it differs from, or
is not defined in PrimitiveParser
.
Expression |
Semantics |
---|---|
|
Instantiate and (default) construct an |
|
Create an |
|
Create an |
|
Create an |
|
Create an |
T
, The numeric base type of the numeric parser.
O(N), where N is the number of digits being parsed plus the sign.
T
For the numeric base type, T
,
the expression requirements below must be valid:
Expression |
Semantics |
---|---|
|
Default construct. |
|
Construct from an |
|
Addition. |
|
Subtraction. |
|
Multiplication. |
|
|
|
Maximum Digits for |
|
Maximum Digits for |
|
Maximum value for |
|
Minimum value for |
Note | |
---|---|
The test harness for the example(s) below is presented in the Basics Examples section. |
Some using declarations:
using boost::spirit::qi::int_;
Basic signed integers:
test_parser("+12345", int_); test_parser("-12345", int_);