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Updated README to reflect the recent change to peg::any

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yhirose 2019-11-25 17:31:13 -05:00
parent 666b364425
commit e4095076e3
1 changed files with 7 additions and 7 deletions
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README.md
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@ -63,18 +63,18 @@ int main(void) {
parser["Additive"] = [](const SemanticValues& sv) { parser["Additive"] = [](const SemanticValues& sv) {
switch (sv.choice()) { switch (sv.choice()) {
case 0: // "Multitive '+' Additive" case 0: // "Multitive '+' Additive"
return sv[0].get<int>() + sv[1].get<int>(); return any_cast<int>(sv[0]) + any_cast<int>(sv[1]);
default: // "Multitive" default: // "Multitive"
return sv[0].get<int>(); return any_cast<int>(sv[0]);
} }
}; };
parser["Multitive"] = [](const SemanticValues& sv) { parser["Multitive"] = [](const SemanticValues& sv) {
switch (sv.choice()) { switch (sv.choice()) {
case 0: // "Primary '*' Multitive" case 0: // "Primary '*' Multitive"
return sv[0].get<int>() * sv[1].get<int>(); return any_cast<int>(sv[0]) + any_cast<int>(sv[1]);
default: // "Primary" default: // "Primary"
return sv[0].get<int>(); return any_cast<int>(sv[0]);
} }
}; };
@ -110,9 +110,9 @@ There are four semantic actions available:
`any& dt` is a 'read-write' context data which can be used for whatever purposes. The initial context data is set in `peg::parser::parse` method. `any& dt` is a 'read-write' context data which can be used for whatever purposes. The initial context data is set in `peg::parser::parse` method.
`peg::any` is a simpler implementatin of [boost::any](http://www.boost.org/doc/libs/1_57_0/doc/html/any.html). It can wrap arbitrary data type. `peg::any` is a simpler implementatin of std::any. If the compiler in use supports C++17, by default `peg::any` is defined as an alias to `std::any`.
If the compiler in use supports C++17, by default `peg::any` is defined as an alias to `std::any`.
To force using the simpler `any` implementation that comes with `cpp-peglib`, define `PEGLIB_USE_STD_ANY` as 0 before including `peglib.h`: To force using the simpler `any` implementation that comes with `cpp-peglib`, define `PEGLIB_USE_STD_ANY` as 0 before including `peglib.h`:
```cpp ```cpp
#define PEGLIB_USE_STD_ANY 0 #define PEGLIB_USE_STD_ANY 0
#include <peglib.h> #include <peglib.h>