1 files changed, 49 insertions, 11 deletions
diff --git a/scripts/cmake/vcpkg_from_github.cmake b/scripts/cmake/vcpkg_from_github.cmake
index f0f8dba8b..0ce485954 100644
--- a/scripts/cmake/vcpkg_from_github.cmake
+++ b/scripts/cmake/vcpkg_from_github.cmake
@@ -1,14 +1,52 @@
-# Usage:
-#   vcpkg_from_github(
-#     OUT_SOURCE_PATH <OutVar for SOURCE_PATH (SOURCE_PATH)>
-#     REPO <Repository (Microsoft/cpprestsdk)>
-#     REF <stable ref (v2.0.0)>
-#     SHA512 <SHA for REF (45d0d7f8cc350...)>
-#     HEAD_REF <unstable branch (master)>
-#   )
-#
-# Notes:
-#   This will export VCPKG_HEAD_VERSION variable during head builds.
+## # vcpkg_from_github
+##
+## Download and extract a project from GitHub. Enables support for `install --head`.
+##
+## ## Usage:
+## ```cmake
+## vcpkg_from_github(
+##     OUT_SOURCE_PATH <SOURCE_PATH>
+##     REPO <Microsoft/cpprestsdk>
+##     [REF <v2.0.0>]
+##     [SHA512 <45d0d7f8cc350...>]
+##     [HEAD_REF <master>]
+## )
+## ```
+##
+## ## Parameters:
+## ### OUT_SOURCE_PATH
+## Specifies the out-variable that will contain the extracted location.
+##
+## This should be set to `SOURCE_PATH` by convention.
+##
+## ### REPO
+## The organization or user and repository on GitHub.
+##
+## ### REF
+## A stable git commit-ish (ideally a tag) that will not change contents.
+##
+## If `REF` is specified, `SHA512` must also be specified.
+##
+## ### SHA512
+## The SHA512 hash that should match the archive (https://github.com/${REPO}/archive/${REF}.tar.gz).
+##
+## This is most easily determined by first setting it to `1`, then trying to build the port. The error message will contain the full hash, which can be copied back into the portfile.
+##
+## ### HEAD_REF
+## The unstable git commit-ish (ideally a branch) to pull for `--head` builds.
+##
+## For most projects, this should be `master`. The chosen branch should be one that is expected to be always buildable on all supported platforms.
+##
+## ## Notes:
+## At least one of `REF` and `HEAD_REF` must be specified.
+##
+## This exports the `VCPKG_HEAD_VERSION` variable during head builds.
+##
+## ## Examples:
+##
+## * [cpprestsdk](https://github.com/Microsoft/vcpkg/blob/master/ports/cpprestsdk/portfile.cmake)
+## * [ms-gsl](https://github.com/Microsoft/vcpkg/blob/master/ports/ms-gsl/portfile.cmake)
+## * [beast](https://github.com/Microsoft/vcpkg/blob/master/ports/beast/portfile.cmake)
 function(vcpkg_from_github)
     set(oneValueArgs OUT_SOURCE_PATH REPO REF SHA512 HEAD_REF)
     set(multipleValuesArgs)