Other libraries encourage you to think of a This is another area in which xpressive differs from other object-oriented To create a regular expression object from a string, you must call a factory Notice how the regex object is initialized:
I'll discuss this difference and its implications in detail later. That this regex can be used to find patterns in std :: string If you are familiar with Boost.Regex, this is different than what you
Next, you'll notice the type of the regular expression object is sregex. Most of the rest of the examples in this document will leave off the using namespace boost :: xpressive Live in the boost :: xpressive namespace.
#Xpressive 2 software code
The first thing you'll notice about the code is that all the types in xpressive #include #include using namespace boost :: xpressive int main () Let's have a look at Hello World, xpressive Will participate fully in the search, back-tracking as needed to make theĮnough theory. In a static regex, or vice versa, and the embedded regex Same program, and even in the same expression! You can embed a dynamic regex In fact, xpressive's interface should be familiar to anyone who has usedĬomes from allowing you to mix and match static and dynamic regexes in the Xpressive does exhaustive backtracking, trying every possibility to findĪ match for your pattern.) Dynamic xpressive is a bit like Boost.Regex. Grammars with static regexes using expression templates. Xpressive's dual nature is unique and powerful. Finally, since they are statically bound, the compilerĬan generate faster code for static regexes. In your program, giving you the ability to call back into your code from Also, they can naturally refer to code and data elsewhere Since they are C++ expressions instead of strings, they can be syntax-checkedĪt compile-time. Have the advantage that they can be accepted from the user as input at runtime Regexes), or as expression templates that are parsed at compile-time (static regexes). Regular expressions (regexes)Ĭan be written as strings that are parsed dynamically at runtime (dynamic Xpressive is a regular expression template library.
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