Jass has troubles with reading reals

[Prometheus3375]

I made a test in WarCraft 3 1.26a. I filled 2 arrays of reals with the powers of 2 from 0 to -13. The first array was filled by 'hand', and the values of the second were produced by computation of WarCraft 3. In addition, I put a check if the same powers stored in arrays will differ. This check requires the loop-return hack.

If you run the code below, the result of the whole test will be stored in <WarCraft 3 directory>\Test\R2SWPrecision.txt.

Spoiler: Code

function R2SWPrecision takes nothing returns nothing
    local real array ByWar3
    local real array ByHand
    local integer a = -1
    local integer k
    local integer max = 9
    call PreloadGenClear()
    set ByHand[0] = 1.
    set ByHand[1] = 0.5
    set ByHand[2] = 0.25
    set ByHand[3] = 0.125
    set ByHand[4] = 0.0625
    set ByHand[5] = 0.03125
    set ByHand[6] = 0.015625
    set ByHand[7] = 0.0078125
    set ByHand[8] = 0.00390625
    set ByHand[9] = 0.001953125
    set ByHand[10] = 0.0009765625 // invalid
    set ByHand[11] = 0.00048828125 // invalid
    set ByHand[12] = 0.000244140625 // invalid
    set ByHand[13] = 0.0001220703125 // invalid
    set ByWar3[0] = 1.
    set ByWar3[1] = ByWar3[0] / 2.
    set ByWar3[2] = ByWar3[1] / 2.
    set ByWar3[3] = ByWar3[2] / 2.
    set ByWar3[4] = ByWar3[3] / 2.
    set ByWar3[5] = ByWar3[4] / 2.
    set ByWar3[6] = ByWar3[5] / 2.
    set ByWar3[7] = ByWar3[6] / 2.
    set ByWar3[8] = ByWar3[7] / 2.
    set ByWar3[9] = ByWar3[8] / 2.
    set ByWar3[10] = ByWar3[9] / 2.
    set ByWar3[11] = ByWar3[10] / 2.
    set ByWar3[12] = ByWar3[11] / 2.
    set ByWar3[13] = ByWar3[12] / 2.
    loop
        set k = 0
        loop
            call Preload("\")    2^(" + I2S(-k) + ") with precision " + I2S(a) + " in ByHand: " + R2SW(ByHand[k], 0, a) + "       //")
            call Preload("\")    2^(" + I2S(-k) + ") with precision " + I2S(a) + " in ByWar3: " + R2SW(ByWar3[k], 0, a) + "       //")
            set k = k + 1
            exitwhen k > max
        endloop
        set a = a + 1
        exitwhen a > 9
    endloop
    set k = 0
    loop
        if ByHand[k] > ByWar3[k] then
            call Preload("\")    ByHand[" + I2S(k) + "] stores bigger value!       //")
            call Preload("\")    Int32 representation of ByHand[" + I2S(k) + "] is " + I2S(cleanInt(realToIndex(ByHand[k]))) + "       //")
            call Preload("\")    Int32 representation of ByWar3[" + I2S(k) + "] is " + I2S(cleanInt(realToIndex(ByWar3[k]))) + "       //")
        elseif ByWar3[k] > ByHand[k] then
            call Preload("\")    ByWar3[" + I2S(k) + "] stores bigger value!       //")
            call Preload("\")    Int32 representation of ByHand[" + I2S(k) + "] is " + I2S(cleanInt(realToIndex(ByHand[k]))) + "       //")
            call Preload("\")    Int32 representation of ByWar3[" + I2S(k) + "] is " + I2S(cleanInt(realToIndex(ByWar3[k]))) + "       //")
        endif
        set k = k + 1
        exitwhen k > max
    endloop
    call PreloadGenEnd("Test\\R2SWPrecision.txt")
endfunction

Output of the code above.

Spoiler: Ouput

function PreloadFiles takes nothing returns nothing

    call Preload( "")    2^(0) with precision -1 in ByHand: 1.0       //" )
    call Preload( "")    2^(0) with precision -1 in ByWar3: 1.0       //" )
    call Preload( "")    2^(-1) with precision -1 in ByHand: 0.5       //" )
    call Preload( "")    2^(-1) with precision -1 in ByWar3: 0.5       //" )
    call Preload( "")    2^(-2) with precision -1 in ByHand: 0.25       //" )
    call Preload( "")    2^(-2) with precision -1 in ByWar3: 0.25       //" )
    call Preload( "")    2^(-3) with precision -1 in ByHand: 0.125       //" )
    call Preload( "")    2^(-3) with precision -1 in ByWar3: 0.125       //" )
    call Preload( "")    2^(-4) with precision -1 in ByHand: 0.0625       //" )
    call Preload( "")    2^(-4) with precision -1 in ByWar3: 0.0625       //" )
    call Preload( "")    2^(-5) with precision -1 in ByHand: 0.03125       //" )
    call Preload( "")    2^(-5) with precision -1 in ByWar3: 0.03125       //" )
    call Preload( "")    2^(-6) with precision -1 in ByHand: 0.015625       //" )
    call Preload( "")    2^(-6) with precision -1 in ByWar3: 0.015625       //" )
    call Preload( "")    2^(-7) with precision -1 in ByHand: 0.007813       //" )
    call Preload( "")    2^(-7) with precision -1 in ByWar3: 0.007813       //" )
    call Preload( "")    2^(-8) with precision -1 in ByHand: 0.003906       //" )
    call Preload( "")    2^(-8) with precision -1 in ByWar3: 0.003906       //" )
    call Preload( "")    2^(-9) with precision -1 in ByHand: 0.001953       //" )
    call Preload( "")    2^(-9) with precision -1 in ByWar3: 0.001953       //" )
    call Preload( "")    2^(0) with precision 0 in ByHand: 1.0       //" )
    call Preload( "")    2^(0) with precision 0 in ByWar3: 1.0       //" )
    call Preload( "")    2^(-1) with precision 0 in ByHand: 1.0       //" )
    call Preload( "")    2^(-1) with precision 0 in ByWar3: 1.0       //" )
    call Preload( "")    2^(-2) with precision 0 in ByHand: 0.0       //" )
    call Preload( "")    2^(-2) with precision 0 in ByWar3: 0.0       //" )
    call Preload( "")    2^(-3) with precision 0 in ByHand: 0.0       //" )
    call Preload( "")    2^(-3) with precision 0 in ByWar3: 0.0       //" )
    call Preload( "")    2^(-4) with precision 0 in ByHand: 0.0       //" )
    call Preload( "")    2^(-4) with precision 0 in ByWar3: 0.0       //" )
    call Preload( "")    2^(-5) with precision 0 in ByHand: 0.0       //" )
    call Preload( "")    2^(-5) with precision 0 in ByWar3: 0.0       //" )
    call Preload( "")    2^(-6) with precision 0 in ByHand: 0.0       //" )
    call Preload( "")    2^(-6) with precision 0 in ByWar3: 0.0       //" )
    call Preload( "")    2^(-7) with precision 0 in ByHand: 0.0       //" )
    call Preload( "")    2^(-7) with precision 0 in ByWar3: 0.0       //" )
    call Preload( "")    2^(-8) with precision 0 in ByHand: 0.0       //" )
    call Preload( "")    2^(-8) with precision 0 in ByWar3: 0.0       //" )
    call Preload( "")    2^(-9) with precision 0 in ByHand: 0.0       //" )
    call Preload( "")    2^(-9) with precision 0 in ByWar3: 0.0       //" )
    call Preload( "")    2^(0) with precision 1 in ByHand: 1.0       //" )
    call Preload( "")    2^(0) with precision 1 in ByWar3: 1.0       //" )
    call Preload( "")    2^(-1) with precision 1 in ByHand: 0.5       //" )
    call Preload( "")    2^(-1) with precision 1 in ByWar3: 0.5       //" )
    call Preload( "")    2^(-2) with precision 1 in ByHand: 0.3       //" )
    call Preload( "")    2^(-2) with precision 1 in ByWar3: 0.3       //" )
    call Preload( "")    2^(-3) with precision 1 in ByHand: 0.1       //" )
    call Preload( "")    2^(-3) with precision 1 in ByWar3: 0.1       //" )
    call Preload( "")    2^(-4) with precision 1 in ByHand: 0.1       //" )
    call Preload( "")    2^(-4) with precision 1 in ByWar3: 0.1       //" )
    call Preload( "")    2^(-5) with precision 1 in ByHand: 0.0       //" )
    call Preload( "")    2^(-5) with precision 1 in ByWar3: 0.0       //" )
    call Preload( "")    2^(-6) with precision 1 in ByHand: 0.0       //" )
    call Preload( "")    2^(-6) with precision 1 in ByWar3: 0.0       //" )
    call Preload( "")    2^(-7) with precision 1 in ByHand: 0.0       //" )
    call Preload( "")    2^(-7) with precision 1 in ByWar3: 0.0       //" )
    call Preload( "")    2^(-8) with precision 1 in ByHand: 0.0       //" )
    call Preload( "")    2^(-8) with precision 1 in ByWar3: 0.0       //" )
    call Preload( "")    2^(-9) with precision 1 in ByHand: 0.0       //" )
    call Preload( "")    2^(-9) with precision 1 in ByWar3: 0.0       //" )
    call Preload( "")    2^(0) with precision 2 in ByHand: 1.00       //" )
    call Preload( "")    2^(0) with precision 2 in ByWar3: 1.00       //" )
    call Preload( "")    2^(-1) with precision 2 in ByHand: 0.50       //" )
    call Preload( "")    2^(-1) with precision 2 in ByWar3: 0.50       //" )
    call Preload( "")    2^(-2) with precision 2 in ByHand: 0.25       //" )
    call Preload( "")    2^(-2) with precision 2 in ByWar3: 0.25       //" )
    call Preload( "")    2^(-3) with precision 2 in ByHand: 0.13       //" )
    call Preload( "")    2^(-3) with precision 2 in ByWar3: 0.13       //" )
    call Preload( "")    2^(-4) with precision 2 in ByHand: 0.06       //" )
    call Preload( "")    2^(-4) with precision 2 in ByWar3: 0.06       //" )
    call Preload( "")    2^(-5) with precision 2 in ByHand: 0.03       //" )
    call Preload( "")    2^(-5) with precision 2 in ByWar3: 0.03       //" )
    call Preload( "")    2^(-6) with precision 2 in ByHand: 0.02       //" )
    call Preload( "")    2^(-6) with precision 2 in ByWar3: 0.02       //" )
    call Preload( "")    2^(-7) with precision 2 in ByHand: 0.01       //" )
    call Preload( "")    2^(-7) with precision 2 in ByWar3: 0.01       //" )
    call Preload( "")    2^(-8) with precision 2 in ByHand: 0.00       //" )
    call Preload( "")    2^(-8) with precision 2 in ByWar3: 0.00       //" )
    call Preload( "")    2^(-9) with precision 2 in ByHand: 0.00       //" )
    call Preload( "")    2^(-9) with precision 2 in ByWar3: 0.00       //" )
    call Preload( "")    2^(0) with precision 3 in ByHand: 1.000       //" )
    call Preload( "")    2^(0) with precision 3 in ByWar3: 1.000       //" )
    call Preload( "")    2^(-1) with precision 3 in ByHand: 0.500       //" )
    call Preload( "")    2^(-1) with precision 3 in ByWar3: 0.500       //" )
    call Preload( "")    2^(-2) with precision 3 in ByHand: 0.250       //" )
    call Preload( "")    2^(-2) with precision 3 in ByWar3: 0.250       //" )
    call Preload( "")    2^(-3) with precision 3 in ByHand: 0.125       //" )
    call Preload( "")    2^(-3) with precision 3 in ByWar3: 0.125       //" )
    call Preload( "")    2^(-4) with precision 3 in ByHand: 0.063       //" )
    call Preload( "")    2^(-4) with precision 3 in ByWar3: 0.063       //" )
    call Preload( "")    2^(-5) with precision 3 in ByHand: 0.031       //" )
    call Preload( "")    2^(-5) with precision 3 in ByWar3: 0.031       //" )
    call Preload( "")    2^(-6) with precision 3 in ByHand: 0.016       //" )
    call Preload( "")    2^(-6) with precision 3 in ByWar3: 0.016       //" )
    call Preload( "")    2^(-7) with precision 3 in ByHand: 0.008       //" )
    call Preload( "")    2^(-7) with precision 3 in ByWar3: 0.008       //" )
    call Preload( "")    2^(-8) with precision 3 in ByHand: 0.004       //" )
    call Preload( "")    2^(-8) with precision 3 in ByWar3: 0.004       //" )
    call Preload( "")    2^(-9) with precision 3 in ByHand: 0.002       //" )
    call Preload( "")    2^(-9) with precision 3 in ByWar3: 0.002       //" )
    call Preload( "")    2^(0) with precision 4 in ByHand: 1.0000       //" )
    call Preload( "")    2^(0) with precision 4 in ByWar3: 1.0000       //" )
    call Preload( "")    2^(-1) with precision 4 in ByHand: 0.5000       //" )
    call Preload( "")    2^(-1) with precision 4 in ByWar3: 0.5000       //" )
    call Preload( "")    2^(-2) with precision 4 in ByHand: 0.2500       //" )
    call Preload( "")    2^(-2) with precision 4 in ByWar3: 0.2500       //" )
    call Preload( "")    2^(-3) with precision 4 in ByHand: 0.1250       //" )
    call Preload( "")    2^(-3) with precision 4 in ByWar3: 0.1250       //" )
    call Preload( "")    2^(-4) with precision 4 in ByHand: 0.0625       //" )
    call Preload( "")    2^(-4) with precision 4 in ByWar3: 0.0625       //" )
    call Preload( "")    2^(-5) with precision 4 in ByHand: 0.0313       //" )
    call Preload( "")    2^(-5) with precision 4 in ByWar3: 0.0313       //" )
    call Preload( "")    2^(-6) with precision 4 in ByHand: 0.0156       //" )
    call Preload( "")    2^(-6) with precision 4 in ByWar3: 0.0156       //" )
    call Preload( "")    2^(-7) with precision 4 in ByHand: 0.0078       //" )
    call Preload( "")    2^(-7) with precision 4 in ByWar3: 0.0078       //" )
    call Preload( "")    2^(-8) with precision 4 in ByHand: 0.0039       //" )
    call Preload( "")    2^(-8) with precision 4 in ByWar3: 0.0039       //" )
    call Preload( "")    2^(-9) with precision 4 in ByHand: 0.0020       //" )
    call Preload( "")    2^(-9) with precision 4 in ByWar3: 0.0020       //" )
    call Preload( "")    2^(0) with precision 5 in ByHand: 1.00000       //" )
    call Preload( "")    2^(0) with precision 5 in ByWar3: 1.00000       //" )
    call Preload( "")    2^(-1) with precision 5 in ByHand: 0.50000       //" )
    call Preload( "")    2^(-1) with precision 5 in ByWar3: 0.50000       //" )
    call Preload( "")    2^(-2) with precision 5 in ByHand: 0.25000       //" )
    call Preload( "")    2^(-2) with precision 5 in ByWar3: 0.25000       //" )
    call Preload( "")    2^(-3) with precision 5 in ByHand: 0.12500       //" )
    call Preload( "")    2^(-3) with precision 5 in ByWar3: 0.12500       //" )
    call Preload( "")    2^(-4) with precision 5 in ByHand: 0.06250       //" )
    call Preload( "")    2^(-4) with precision 5 in ByWar3: 0.06250       //" )
    call Preload( "")    2^(-5) with precision 5 in ByHand: 0.03125       //" )
    call Preload( "")    2^(-5) with precision 5 in ByWar3: 0.03125       //" )
    call Preload( "")    2^(-6) with precision 5 in ByHand: 0.01563       //" )
    call Preload( "")    2^(-6) with precision 5 in ByWar3: 0.01563       //" )
    call Preload( "")    2^(-7) with precision 5 in ByHand: 0.00781       //" )
    call Preload( "")    2^(-7) with precision 5 in ByWar3: 0.00781       //" )
    call Preload( "")    2^(-8) with precision 5 in ByHand: 0.00391       //" )
    call Preload( "")    2^(-8) with precision 5 in ByWar3: 0.00391       //" )
    call Preload( "")    2^(-9) with precision 5 in ByHand: 0.00195       //" )
    call Preload( "")    2^(-9) with precision 5 in ByWar3: 0.00195       //" )
    call Preload( "")    2^(0) with precision 6 in ByHand: 1.000000       //" )
    call Preload( "")    2^(0) with precision 6 in ByWar3: 1.000000       //" )
    call Preload( "")    2^(-1) with precision 6 in ByHand: 0.500000       //" )
    call Preload( "")    2^(-1) with precision 6 in ByWar3: 0.500000       //" )
    call Preload( "")    2^(-2) with precision 6 in ByHand: 0.250000       //" )
    call Preload( "")    2^(-2) with precision 6 in ByWar3: 0.250000       //" )
    call Preload( "")    2^(-3) with precision 6 in ByHand: 0.125000       //" )
    call Preload( "")    2^(-3) with precision 6 in ByWar3: 0.125000       //" )
    call Preload( "")    2^(-4) with precision 6 in ByHand: 0.062500       //" )
    call Preload( "")    2^(-4) with precision 6 in ByWar3: 0.062500       //" )
    call Preload( "")    2^(-5) with precision 6 in ByHand: 0.031250       //" )
    call Preload( "")    2^(-5) with precision 6 in ByWar3: 0.031250       //" )
    call Preload( "")    2^(-6) with precision 6 in ByHand: 0.015625       //" )
    call Preload( "")    2^(-6) with precision 6 in ByWar3: 0.015625       //" )
    call Preload( "")    2^(-7) with precision 6 in ByHand: 0.007813       //" )
    call Preload( "")    2^(-7) with precision 6 in ByWar3: 0.007813       //" )
    call Preload( "")    2^(-8) with precision 6 in ByHand: 0.003906       //" )
    call Preload( "")    2^(-8) with precision 6 in ByWar3: 0.003906       //" )
    call Preload( "")    2^(-9) with precision 6 in ByHand: 0.001953       //" )
    call Preload( "")    2^(-9) with precision 6 in ByWar3: 0.001953       //" )
    call Preload( "")    2^(0) with precision 7 in ByHand: 1.0000000       //" )
    call Preload( "")    2^(0) with precision 7 in ByWar3: 1.0000000       //" )
    call Preload( "")    2^(-1) with precision 7 in ByHand: 0.5000000       //" )
    call Preload( "")    2^(-1) with precision 7 in ByWar3: 0.5000000       //" )
    call Preload( "")    2^(-2) with precision 7 in ByHand: 0.2500000       //" )
    call Preload( "")    2^(-2) with precision 7 in ByWar3: 0.2500000       //" )
    call Preload( "")    2^(-3) with precision 7 in ByHand: 0.1250000       //" )
    call Preload( "")    2^(-3) with precision 7 in ByWar3: 0.1250000       //" )
    call Preload( "")    2^(-4) with precision 7 in ByHand: 0.0625000       //" )
    call Preload( "")    2^(-4) with precision 7 in ByWar3: 0.0625000       //" )
    call Preload( "")    2^(-5) with precision 7 in ByHand: 0.0312500       //" )
    call Preload( "")    2^(-5) with precision 7 in ByWar3: 0.0312500       //" )
    call Preload( "")    2^(-6) with precision 7 in ByHand: 0.0156250       //" )
    call Preload( "")    2^(-6) with precision 7 in ByWar3: 0.0156250       //" )
    call Preload( "")    2^(-7) with precision 7 in ByHand: 0.0078125       //" )
    call Preload( "")    2^(-7) with precision 7 in ByWar3: 0.0078125       //" )
    call Preload( "")    2^(-8) with precision 7 in ByHand: 0.0039063       //" )
    call Preload( "")    2^(-8) with precision 7 in ByWar3: 0.0039063       //" )
    call Preload( "")    2^(-9) with precision 7 in ByHand: 0.0019531       //" )
    call Preload( "")    2^(-9) with precision 7 in ByWar3: 0.0019531       //" )
    call Preload( "")    2^(0) with precision 8 in ByHand: 1.00000000       //" )
    call Preload( "")    2^(0) with precision 8 in ByWar3: 1.00000000       //" )
    call Preload( "")    2^(-1) with precision 8 in ByHand: 0.50000000       //" )
    call Preload( "")    2^(-1) with precision 8 in ByWar3: 0.50000000       //" )
    call Preload( "")    2^(-2) with precision 8 in ByHand: 0.25000000       //" )
    call Preload( "")    2^(-2) with precision 8 in ByWar3: 0.25000000       //" )
    call Preload( "")    2^(-3) with precision 8 in ByHand: 0.12500000       //" )
    call Preload( "")    2^(-3) with precision 8 in ByWar3: 0.12500000       //" )
    call Preload( "")    2^(-4) with precision 8 in ByHand: 0.06250000       //" )
    call Preload( "")    2^(-4) with precision 8 in ByWar3: 0.06250000       //" )
    call Preload( "")    2^(-5) with precision 8 in ByHand: 0.03125000       //" )
    call Preload( "")    2^(-5) with precision 8 in ByWar3: 0.03125000       //" )
    call Preload( "")    2^(-6) with precision 8 in ByHand: 0.01562500       //" )
    call Preload( "")    2^(-6) with precision 8 in ByWar3: 0.01562500       //" )
    call Preload( "")    2^(-7) with precision 8 in ByHand: 0.00781250       //" )
    call Preload( "")    2^(-7) with precision 8 in ByWar3: 0.00781250       //" )
    call Preload( "")    2^(-8) with precision 8 in ByHand: 0.00390625       //" )
    call Preload( "")    2^(-8) with precision 8 in ByWar3: 0.00390625       //" )
    call Preload( "")    2^(-9) with precision 8 in ByHand: 0.00195313       //" )
    call Preload( "")    2^(-9) with precision 8 in ByWar3: 0.00195313       //" )
    call Preload( "")    2^(0) with precision 9 in ByHand: 1.000000000       //" )
    call Preload( "")    2^(0) with precision 9 in ByWar3: 1.000000000       //" )
    call Preload( "")    2^(-1) with precision 9 in ByHand: 0.500000000       //" )
    call Preload( "")    2^(-1) with precision 9 in ByWar3: 0.500000000       //" )
    call Preload( "")    2^(-2) with precision 9 in ByHand: 0.250000000       //" )
    call Preload( "")    2^(-2) with precision 9 in ByWar3: 0.250000000       //" )
    call Preload( "")    2^(-3) with precision 9 in ByHand: 0.125000000       //" )
    call Preload( "")    2^(-3) with precision 9 in ByWar3: 0.125000000       //" )
    call Preload( "")    2^(-4) with precision 9 in ByHand: 0.062500000       //" )
    call Preload( "")    2^(-4) with precision 9 in ByWar3: 0.062500000       //" )
    call Preload( "")    2^(-5) with precision 9 in ByHand: 0.031250002       //" )
    call Preload( "")    2^(-5) with precision 9 in ByWar3: 0.031250000       //" )
    call Preload( "")    2^(-6) with precision 9 in ByHand: 0.015625000       //" )
    call Preload( "")    2^(-6) with precision 9 in ByWar3: 0.015625000       //" )
    call Preload( "")    2^(-7) with precision 9 in ByHand: 0.007812500       //" )
    call Preload( "")    2^(-7) with precision 9 in ByWar3: 0.007812500       //" )
    call Preload( "")    2^(-8) with precision 9 in ByHand: 0.003906250       //" )
    call Preload( "")    2^(-8) with precision 9 in ByWar3: 0.003906250       //" )
    call Preload( "")    2^(-9) with precision 9 in ByHand: 0.001953125       //" )
    call Preload( "")    2^(-9) with precision 9 in ByWar3: 0.001953125       //" )
    call Preload( "")    ByHand[5] stores bigger value!       //" )
    call Preload( "")    Int32 representation of ByHand[5] is 1023410177       //" )
    call Preload( "")    Int32 representation of ByWar3[5] is 1023410176       //" )
    call Preload( "")    ByHand[7] stores bigger value!       //" )
    call Preload( "")    Int32 representation of ByHand[7] is 1006632961       //" )
    call Preload( "")    Int32 representation of ByWar3[7] is 1006632960       //" )
    call PreloadEnd( 31767.1 )

endfunction

If you assign to max 13, you will see that array ByHand simply stores incorrect values in cells 10-13.

So, the first problem: Jass sometimes fails to read reals correctly, even if these reals have precise representations in the float. Powers of 2 actually do have.

I converted int32 representations of 'failed' reals to hexes using this converter. Then I converted hexes to floats using this converter. The result is written below.

ByHand[5] actually stores 0.0312500037252902984619140625.
ByWar3[5] stores 0.03125.
ByHand[7] actually stores 0.007812500931322574615478515625.
ByWar3[7] stores 0.0078125.

You may know that R2SW uses mathematical rounding. Therefore, statements below are true.

R2SW(ByHand[5], 0, 9) must output 0.031250004.
R2SW(ByHand[7], 0, 9) must output 0.007812501.

But you can see from my test what R2SW actually returns for 'failed' values.

R2SW(ByHand[5], 0, 9) outputs 0.031250002.
R2SW(ByHand[7], 0, 9) outputs 0.007812500.

Here is the second problem: R2SW sometimes returns strings that are not correct.



Let's summarize:

1. Jass sometimes fails to read reals correctly, even if these reals have precise representations in the float.
2. R2SW sometimes returns strings that are not correct.

These two statements are true for WarCraft 3 1.26a.

I want someone to run that code in the latest official patch of WarCraft 3 or in PTR. If the same problems occur, then it is necessary to report them to developers. You can comment the code that uses the loop-return hack, if it is fixed in latest versions.

 

[Lizreu]

Looks like an artifact in the JASS interpreter to be honest. This is definitely very interesting (and rather disconcerning, to say the least), and I want to take a look at it myself in 1.29. Will do so some time later.

 

[EdgeOfChaos]

Another implementation fail: even though it should be able to hold quite high numbers (at least 1E38), reals have the same limit as integers (2.14 billion). Makes no sense, but its how it is

 

[Lizreu]

Alright, my personal observations on patch 1.29:

1. I can't see much wrong with R2SW itself. It occasionally rounds up the last decimal (i.e. 0.0009765625 gets turned into 0.000976563) and only supports up to 9 decimal places, which is weird, but whatever. The fact that it returns mucked up strings for mucked up reals (when defined as literals in the script) isn't really telling, though it certainly is weird.

2. I can confirm that the JASS interpreter majorly screws up the reals fed to it on the latest patch. Sometimes it even turns them negative! Like 0.000244140625 turns into -0.335643904 - wtf?

It looks like JASS only supports reals with a decimal representation with no more than 9 decimal places. This is further reassured by the fact that R2SW returns only up to 9 decimal places, so I take a guess that this is somehow related.

Either way, you're right that it should be reported, since it's still broken in 1.29.

 

[MyPad]

It's a good thing I use division operations when representing common small intervals.

constant real INTERVAL = 1/32.
// Take that, 0.0312500000

Since this compiler error still persists, I don't see why this shouldn't be reported.

With the courtesy of @Prometheus3375, I will submit this parser error in the Compiled List of Bugs thread.