Split out new module StdEffects from OpenSums (#34)
Rename ITree.ITree to ITree.Core (core definitions), freeing up ITree.ITree for the standard way to open the library.
Operations defined in Core are further wrapped in an ITree module, the intent is that they should be used qualified. (I've had problems caused by shadowing bind and map.)
itree is still at the root of Core so it doesn't need to be qualified, but its actual name is now ITree.Core.itree; we could add notations inside the inner ITree module to "rename" it.
Add embed, yet one more variant of lift, etc., but probably the easiest one to use when defining new effects (see examples/IO.v for example).
StdEffectsfromOpenSums(#34)ITree.ITreetoITree.Core(core definitions), freeing upITree.ITreefor the standard way to open the library.Coreare further wrapped in anITreemodule, the intent is that they should be used qualified. (I've had problems caused by shadowingbindandmap.)itreeis still at the root ofCoreso it doesn't need to be qualified, but its actual name is nowITree.Core.itree; we could add notations inside the innerITreemodule to "rename" it.embed, yet one more variant oflift, etc., but probably the easiest one to use when defining new effects (seeexamples/IO.vfor example).