Numeric Literals (Summary)

[Michael Lazzaro]

W/ regards to numeric literals, here are a number of examples/proposals that we should verify the behavior of. Anything I missed?

decimal: (meaning?)
123 # int 123
0123 # int 123
123.0 # num 123.0
-123 # int -123

0_1.2_3 # ok
_01.23 # wrong
01.23_ # wrong
01_._23 # wrong?
1__2 # wrong

exponential:
-1.23e4 # num
-1.23E4 # num (identical)

1.23_e_4 # ok?

bin/oct/hex literals:

0b0110 # bin
0c0123 # oct
0x00ff # hex
0x00fF # hex, == 0x00ff
0x00FF # hex, == 0x00ff

0xf_f # ok
0x_ff # ok

explicit radix:

20:1gk # base 20
20:1GK # base 20 (identical)
20:1.G.K # base 20 (identical?)
20:1_G_K # base 20 (identical?)
20:1.16.19 # base 20 (identical?)
20:1_16_19 # base 20 (identical?)

62:zZ # base 62 (?)
62:z.Z # base 62 (identical?)
62:z_Z # base 62 (identical?)
62:Zz # base 62 (not identical?)

256:0.253.254.255 # base 256
256:0_253_254_255 # base 256

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Of course, a key issue is that, in perl5, the treatment of numeric literals is not at all the same as the treatment of stringified numerics. For example:

0x00ff # hex value ff
'0x00ff' # integer value 0, with trailing 'x00ff'

I think ways to solve this should be open to discussion. Hopefully Luke can give us some proposals, since he's writing that part.

MikeL