Quirks

The BrightScript language has a whole bunch of quirks. This page attempts to capture them as I find them. In general, a quirk listed here is supported in the brs project's interpreter.

Maximum Number of Arguments in a Function Signature

BrightScript functions and subs can accept 63 arguments, and the brs project matches that. Including a 64th argument results in early argument types getting "forgotten". This typically presents as a Type mismatch error where the first few arguments have type ?, e.g.:

sub tooMany(a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p, q, r, s, t, u, v, w, x, y, z, aa, ab, ac, ad, ae, af, ag, ah, ai, aj, ak, al, am, an, ao, ap, aq, ar, as, at, au, av, aw, ax, ay, az, ba, bb, bc, bd, be, bf, bg, bh, bi, bj, bk, bl)
    print "BrightScript supports at most 63 arguments"
end sub

tooMany(1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)

Current Function:                                                                                                      
005:* sub tooMany(a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p, q, r, s, t, u, v, w, x, y, z, aa, ab, ac, ad, ae, af, ag, ah, ai, aj, ak, al, am, an, ao, ap, aq, ar, as, at, au, av, aw, ax, ay, az, ba, bb                                 
006:      ' , ca, cb, cc, cd, ce, cf, cg, ch, ci, cj, ck, cl, cm, cn, co, cp, cq, cr, cs, ct, cu)                      
007:      print "BrightScript supports at most 64 arguments"                                                           
008:  end sub                                                                                                          
Type Mismatch. (runtime error &h18) in pkg:/testfiles/function-max-arg-length.brs(5)                                   
005: sub tooMany(a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p, q, r, s, t, u, v, w, x, y, z, aa, ab, ac, ad, ae, af, ag, ah, ai, aj, ak, al, am, an, ao, ap, aq, ar, as, at, au, av, aw, ax, ay, az, ba, bb                                  
Backtrace:                                                                                                             
#1  Function toomany(a As ?, b As Dynamic, c As Dynamic, d As Dynamic, e As Dynamic, f As Dynamic, g As Dynamic, h As Dynamic, i As Dynamic, j As Dynamic, k As Dynamic, l As Dynamic, m As Dynamic, n As Dynamic, o As Dynamic, p As Dynamic, 
q As Dynamic, r As Dynamic, s As Dynamic, t As Dynamic, u As Dynamic, v As Dynamic, w As Dynamic, x As Dynamic, y As Dynamic, z As Dynamic, aa As Dynamic, ab As Dynamic, ac As Dynamic, ad As Dynamic, ae As Dynamic, af As Dynamic, ag As Dyn
amic, ah As Dynamic, ai As Dynamic, aj As Dynamic, ak As Dynamic, al As Dynamic, am As Dynamic, an As Dynamic, ao As Dynamic, ap As Dynamic, aq As Dynamic, ar As Dynamic, as As Dynamic, at As Dynamic, au As Dynamic, av As Dynamic, aw As Dy
namic, ax As Dynamic, ay As Dynamic, az As Dynamic, ba As Dynamic, bb As Dynamic, bc As Dynamic, bd As Dynamic, be As Dynamic, bf As Dynamic, bg As Dynamic, bh As Dynamic, bi As Dynamic, bj As Dynamic, bk As Dynamic, bl As Dynamic) As Void

Unlike the official interpreter, including a 64th argument in brs will result in a clear runtime error. Including many more arguments is likely to crash a Roku device, causing a sudden reboot. brs doesn't shell out to shutdown -r because that'd be really annoying. You'll just get an error message.