Compiler implementation of the D programming language.
A Statement tree walker that will visit each Statement s in the tree, in depth-first evaluation order, and call fp(s,param) on it. fp() signals whether the walking continues with its return value:
    © 1999–2019 The D Language Foundation
Licensed under the Boost License 1.0.
    https://dlang.org/phobos/dmd_sapply.html