service Math("math"):
    -- x + y
    add(x: i64, y: i64) -> i64
    -- x - y
    sub(x: i64, y: i64) -> i64
    -- x * y
    mul(x: i64, y: i64) -> i64
    -- floor(x * y)
    fmul(x: f64, y: f64) -> i64
    -- x / y
    div(x: i64, y: i64) -> i64
    -- division remainder, x % y
    rem(x: i64, y: i64) -> i64
    -- x^y
    pow(x: i64, y: u32) -> i64
    -- logarithm of y to base x
    -- x – logarithm base
    log(x: i64, y: i64) -> u32

service Compare("cmp"):
    -- x > y
    gt(x: i64, y: i64) -> bool
    -- x >= y
    gte(x: i64, y: i64) -> bool
    -- x < y
    lt(x: i64, y: i64) -> bool
    -- x <= y
    lte(x: i64, y: i64) -> bool
    -- compare x and y
    -- x < y, return -1
    -- x = y, return 0
    -- x > y, return 1
    cmp(x: i64, y: i64) -> i8


service Array("array"):
    -- sum of all numbers in array
    sum(xs: []i64) -> i64
    -- remove duplicates, not stable
    dedup(xs: []string) -> []string
    -- set-intersection of two arrays, not stable, deduplicates
    intersect(xs: []string, ys: []string) -> []string
    -- set-difference of two arrays, not stable, deduplicates
    diff(xs: []string, ys: []string) -> []string
    -- symmetric difference of two arrays, not stable, deduplicates
    sdiff(xs: []string, ys: []string) -> []string