local fis = require 'fis.init'

local fn = fis.Membership

local E = fis.Engine
local V = fis.Variables
local T = fis.Terms

local If = fis.Rules.build_rule
local P = fis.Propositions.create_proposition

local engine = E{name = 'inference engine'}

local fuzzy_input = engine:add_input( V('input variable', 0, 10, 101) )
  :add_term(T('input term', fn.trimf, {0, 0, 5}))

local fuzzy_output = engine:add_output( V('output variable', 0, 10, 101) )
  :add_term(T('output term', fn.trapmf, {0, 0, 5, 10}))

local fuzzy_rules = engine:add_rules{
  If( P(fuzzy_input, 'input term') ).Then{{ fuzzy_output, 'output term' }},
  ...
}