Absyn : term quotation -> Absyn.absyn
APP(APP(IDENT "LET", LAM(VIDENT "x", IDENT "e2")), IDENT "e1")The record syntax `rec.fld1` is converted into something of the form
APP(IDENT "....fld1", IDENT "rec")where the dots will actually be equal to the value of GrammarSpecials.recsel_special (a string).