-- Regression guard for the Lua 5.1 FFI of Data.Number.Format.

-- Expected values come from the module docstring (Format.purs) = the JS

-- toPrecision/toFixed/toExponential/toString contract.

--

-- #92 toPrecisionNative: %g (d significant digits), not %f (d decimals).

-- #95 toExponentialNative: minimal exponent digits (e+3), not zero-padded (e+03).

-- #96 toString: "Infinity"/"-Infinity"/"NaN" for specials, not Lua "inf"/"nan".

-- Accepted divergences (per the number-format calibration): %g strips trailing

-- zeros toPrecision would keep; finite toString keeps Lua's %.14g precision;

-- toFixed uses banker's rounding at exact halves (#99).

--

-- Run from the repo root: `lua test/regression/format.lua`.

local M = assert(dofile("src/Data/Number/Format.lua"))

local failures = 0

local function check(name, got, want)

if got == want then

print("ok - " .. name)

else

failures = failures + 1

print("FAIL - " .. name .. ": got " .. tostring(got) .. ", want " .. tostring(want))

end

end

-- #92 toPrecision: significant digits

check("toPrecision 6 of 1234.56789", M.toPrecisionNative(6)(1234.56789), "1234.57")

check("toPrecision 3 of 0.000123456", M.toPrecisionNative(3)(0.000123456), "0.000123")

-- #95 toExponential: minimal exponent digits

check("toExponential 2 of 1234.56789", M.toExponentialNative(2)(1234.56789), "1.23e+3")

check("toExponential 3 of 0.000123", M.toExponentialNative(3)(0.000123), "1.230e-4")

check("toExponential 0 of 5.0", M.toExponentialNative(0)(5.0), "5e+0")

-- two-digit exponents must stay intact (no over-stripping)

check("toExponential 2 of 1e12 keeps e+12", M.toExponentialNative(2)(1e12), "1.00e+12")

-- toFixed still uses %f (the prior %d->%f fix); semantics check, not rounding edge

check("toFixed 3 of 1234.56789", M.toFixedNative(3)(1234.56789), "1234.568")

-- #96 toString: special values

check("toString NaN", M.toString(0 / 0), "NaN")

check("toString +Infinity", M.toString(math.huge), "Infinity")

check("toString -Infinity", M.toString(-math.huge), "-Infinity")

-- finite values still produce a string (precision divergence accepted)

do

local s = M.toString(42.0)

check("toString finite is a string", type(s), "string")

end

if failures > 0 then error(failures .. " regression check(s) failed") end

print("purescript-lua-numbers (Format): all FFI regression checks passed")