bmi.lua

tbl = {
  {
    name='Very severely underweight',
    upper=15
  },
  {
    name='Severely underweight',
    lower=15,
    upper=16
  },
  {
    name='Underweight',
    lower=16,
    upper=18.5
  },
  {
    name='Normal',
    lower=18.5,
    upper=25
  },
  {
    name='Overweight',
    lower=25,
    upper=30
  },
  {
    name='Moderately obese',
    lower=30,
    upper=35
  },
  {
    name='Severely obese',
    lower=35,
    upper=40
  },
  {
    name='Very severely obese',
    lower=40
  }
}

bmi = 93.7 / 1.68 ^ 2
bmi_classification = ''

for index, classification in ipairs(tbl) do
  lower = true
  upper = true

  if classification['lower'] then
    lower = bmi >= classification['lower']
  end

  if classification['upper'] then
    upper = bmi < classification['upper']
  end

  if lower and upper then
    bmi_classification = classification.name
    bmi_lower = 'lower ' .. (classification['lower'] or '')
    bmi_upper = 'upper ' .. (classification['upper'] or '')
    break
  end
end

print(bmi, bmi_classification, bmi_lower, bmi_upper)