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Macro BOOST_PROTO_DEFINE_ENV_VAR

BOOST_PROTO_DEFINE_ENV_VAR — Define a type and a global variable of that type that can be used to initialize a slot in a Proto transform environment.

Synopsis

// In header: <boost/proto/transform/env.hpp>

BOOST_PROTO_DEFINE_ENV_VAR(Type, Name)

Description

Proto primitive transforms can optionally accept an environment in their third parameter which is a key/value store of environment variables. Use the BOOST_PROTO_DEFINE_ENV_VAR() macro to define the keys.

See the description for proto::data_type for an example of the class interface created by this macro.

Example:

proto::when< _, proto::_env_var<proto::terminal<


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