param1          "--param1 "          i  (1, 10) | mode %in% c("x1", "x2")
param2          "--param2 "          i  (1, 10) | mode %in% c("x1", "x3") & real > 2.5 & real <= 3.5
mode            "--"                 c  ("x1" ,"x2", "x3")
real            "--paramreal="       r  (1.5, 4.5)
mutation        "--mutation="        o  ("none", "very low", "low", "medium", "high", "very high", "all")
fixed           "--fixed "           c  ("fixed")
#unused         "-u "                c  (1, 2, 10, 20)

[forbidden]
## The format is one constraint per line. Each constraint is a logical
## expression (in R syntax). If a parameter configuration
## is generated that makes the logical expression evaluate to TRUE,
## then the configuration is discarded.
##
## Examples of valid logical operators are: ==  !=  >=  <=  >  <  &  |  !  %in%
param1 < 5 & mode == "x1"
(param2 > 6 & mode == "x1") | (param2 <= 6 & mode == "x3")
real < 4 & mode %in% c("x2", "x3")