C representation: introduce assignment; actions subsume expressions.
C representation: introduce assignment; actions subsume expressions.

 * introduce assignment, and hence lvalues.  Currently lvalues are
   variables or index expressions:

     lvalue ::= local-variable
                lvalue [ expression ]

 * Expressions can now appear wherever effectful computations can appear.

yallop/ocaml-ctypes,sjfloat/ocaml-ctypes,whitequark/ocaml-ctypes,dsheets/ocaml-ctypes,dsheets/ocaml-ctypes,whitequark/ocaml-ctypes,ocamllabs/ocaml-ctypes,dsheets/ocaml-ctypes,fdopen/ocaml-ctypes,fdopen/ocaml-ctypes,sjfloat/ocaml-ctypes,sjfloat/ocaml-ctypes,whitequark/ocaml-ctypes,fdopen/ocaml-ctypes,ocamllabs/ocaml-ctypes,yallop/ocaml-ctypes