MichaelChirico
commented
4 years ago Our documentation doesn't say we support hex literals for floating point values, so all of these could be treated as syntax errors. However, we do support C99 notation "0x11.1p0" as you saw, so really the bugs here are that we aren't catching malformed literals like 0x11.1, or 0x1.1.1, etc., and that we don't document that we expect C99 conventions.
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- Comment author - Duncan Murdoch
- Timestamp - 2013-05-12 16:40:28 UTC
GNU R does not parse floating point hexadecimal literals correctly.
In notation without exponent part GNU R discards decimal points when parsing hexadecimal literals:
0x111 # Result: 273 # Status: OK
0x11.1 # Result: 273 # Status: should be 17.0625
0x1.1.1 # Result: 273 # Status: should raise an error
0x....1....1....1 # Result: 273 # Status: should raise an error
In notation with exponent ([pP] option) last decimal point is taken into consideration and all earlier decimal points are ignored:
0x11.1p0 # Result: 17.0625 # Status: OK
0x1.1.1p0 # Result: 17.0625 # Status: should raise an error
0x....1....1....1p0 # Result: 17.0625 # Status: should raise an error
Additionally hexadecimal literals are documented very briefly in "R Language Definition" document.
Bug manifests itself on Windows:
R version 2.15.0 (2012-03-30) Platform: x86_64-pc-mingw32/x64 (64-bit)
locale: [1] LC_COLLATE=Polish_Poland.1250 LC_CTYPE=Polish_Poland.1250
[3] LC_MONETARY=Polish_Poland.1250 LC_NUMERIC=C
[5] LC_TIME=Polish_Poland.1250
attached base packages: [1] stats graphics grDevices utils datasets methods base
and under Linux:
R version 2.15.1 (2012-06-22) Platform: x86_64-pc-linux-gnu (64-bit)
locale: [1] C
attached base packages: [1] stats graphics grDevices utils datasets methods base
other attached packages: [1] seqinr_3.0-6 ade4_1.5-0
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