Don't allow `1:length(vector)`

[Dasonk]

Strict produces an error when one uses something that results in 1:0. The goal here being to prevent cases where someone uses 1:length(x) which can produce 1:0 when x is empty.

It seems to me the strict package is intended to help catch errors before they actually occur. If that's the case then it should warn about any uses of code that looks like 1:length(x) regardless of if it produces 1:0 or 1:10.

[bbolker]

make 'em use seq()! (this would also prevent the 1:n-1 == 0:(n-1) operator-precedence confusion ...)

[torfason]

make 'em use seq()! (this would also prevent the 1:n-1 == 0:(n-1) operator-precedence confusion ...)

seq() is no better:

seq(1,0)
#> [1] 1 0

I typically include a function I once created and called safer_seq() with a similar purpose as the strict functions:

function (from, to) 
{
    stopifnot(round(from) == from)
    stopifnot(round(to) == to)
    stopifnot(to >= from - 1)
    return(seq_len(1 + to - from) + from - 1)
}

Perhaps a strict_seq() should be added to strict?