Env (b0.B0_memo.Env)

val var : empty_is_none:bool -> B0_std.Os.Env.var_name -> t -> string option

var name m looks up variable name in m's env.

val var' : 
  empty_is_none:bool ->
  (B0_std.Os.Env.var_name -> ('a, string) Stdlib.result) ->
  B0_std.Os.Env.var_name ->
  t ->
  'a option

var' m parse name looks up name in m's env and parses it with parse. This B0_memo.fails the memo in case of error.

val var_exists : B0_std.Os.Env.var_name -> t -> bool

var_exists var m is true if var is defined in m's env, even if empty.