Many of these functions are quite the head scratchers if you don't know
what they're trying to do. Document them.
Also make it clear which functions rewrite expressions in-place and
which return new expressions. This prevents memory errors.
No functional changes. Only comments added.
Signed-off-by: Ulf Magnusson <ulfalizer@gmail.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Christian Lamparter <chunkeey@gmail.com>