Overhaul seq() to be more full-featured and R consistent - part II

[hcirellu]

In addition to #202 I brought seq.integer64 closer to seq for integer.

The arguments from, to and by are coerced to integer64. If the coercion would result in an information loss, a warning is displayed. Since the coercion of length.out has no warning with integer, I didn't add it here.

seq(as.integer64(1L), 2.5)
# integer64
# [1] 1 2
# Warning message:
# In seq.integer64(as.integer64(1L), 2.5) :
#   argument 'to' is coerced to integer64

I also added some warnings that give a hint, that because of staying in integer64 the step width is truncated to integer64.

seq(as.integer64(10L), 20L, length.out=4L)
# integer64
# [1] 10 13 16 19
# Warning message:
# In seq.integer64(as.integer64(10L), 20L, length.out = 4L) :
#   the resulting 'by' is truncated to integer64

In addition, I added an error message, if the resulting sequence does not fit in integer64 anymore. Im my opinion this is better than getting a sequence with NA values.

seq(as.integer64(2^62), by=as.integer64(2^62), length.out=2L)
# Error in seq.integer64(as.integer64(2^62), by = as.integer64(2^62), length.out = 2L) : 
#   resulting sequence does not fit in integer64

I also fixed the missing dispatch of :.integer64 and made that also more consistent with R.

I also extended the tests for :.integer64 and seq.integer64.

Adresses (#211)

[MichaelChirico]

Because it involves throwing a new warning where there was none before, I propose waiting until after the next release to consider this change.

[hcirellu]

Just have in mind, that with the actual main branch the following results differ from seq() in R.

seq(NA_integer64_)
# Error
seq(NA)
# [1] 1

seq(rep(NA_integer64_, 2))
# Error
seq(rep(NA, 2))
# [1] 1 2

seq.integer64()
# Error
seq()
# [1] 1

seq(as.integer64())
# Error
seq(as.integer64())
# integer(0)

seq(as.integer64(1:2))
# Error
seq(1:2)
# [1] 1 2

seq(as.integer64(1L), 10L, alon=NULL)
# integer64
# [1] 1 2 3 4 5 6 7 8 9 10
seq(1L, 10L, alon=NULL)
# integer(0)

seq(as.integer64(1L), 10L, by=NULL)
# integer64
# [1] 1 2 3 4 5 6 7 8 9 10
seq(1L, 10L, by=NULL)
# Error: 'by' must be of length 1

seq(as.integer64(1L), 10L, len=NULL)
# integer64
# [1] 1 2 3 4 5 6 7 8 9 10
seq(1L, 10L, len=NULL)
# Error: 'length.out' must be of length 1

seq(by=as.integer64(1:2))
# integer64
# [1] 1
seq(by=1:2)
# Error: 'by' must be of length 1

seq(len=as.integer64(1:2))
# Error
seq(len=1:2)
# 1
warning: first element used of 'length.out' argument

The following examples result in different error messages.

seq(NA_integer64_, 2L)
# Error: missing value where TRUE/FALSE needed
seq(NA, 2L)
# Error: 'from' must be a finite number

seq(to=NA_integer64_, 2L)
# Error: missing value where TRUE/FALSE needed
seq(to=NA, 2L)
# Error: 'to' must be a finite number

seq(len=NA_integer64_, 2L)
# Error: missing value where TRUE/FALSE needed
seq(len=NA, 2L)
# Error: 'length.out' must be a non-negative number

seq(as.integer64(1:2), 10L)
# Error: 'length = 2' in coercion to 'logical(1)'
seq(1:2, 10L)
# Error: 'from' must be of length 1

seq(to=as.integer64(1:2))
# Error: 'length = 2' in coercion to 'logical(1)'
seq(to=1:2)
# Error: 'to' must be of length 1