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Bug #13848

BigDecimal.new('200.') raises an exception

Added by ddoherty03 (Daniel Doherty) 25 days ago. Updated 17 days ago.

Status:
Open
Priority:
Normal
Assignee:
-
Target version:
-
ruby -v:
ruby 2.4.1p111 (2017-03-22 revision 58053) [x86_64-linux]
[ruby-core:82512]

Description

BigDecimal.new('200.') raises an exception:

ArgumentError: invalid value for BigDecimal(): "200."

It should accept this as a valid decimal number.

This requires fixing numbers read in from the wild.

History

#1 [ruby-core:82514] Updated by shevegen (Robert A. Heiler) 25 days ago

I believe you mean for BigDecimal.new('200.') to be equivalent to BigDecimal.new('200.0')?

I could see both ways be ok; there may be use cases where the error is better because of
the user not being explicit enough; or the user does not want to have to type in the
trailing '0'. So I can't say whether this is really a bug or not, it may be specifically
wanted to be that way.

I guess if there are no trade offs though, then I'd agree with the proposal if you meant
that it is the same to mean for a trailing '0' there - but I could also see for purity
to require the '0' to be passed.

What about input such as:

BigDecimal.new('0.')

I mean it will be 0 anyway... it reads strangely to omit the the '0' to my eyes though ...

Latest docu can be found here, if anyone else is interested:

https://ruby-doc.org/stdlib/libdoc/bigdecimal/rdoc/BigDecimal.html

#2 [ruby-core:82534] Updated by ddoherty03 (Daniel Doherty) 24 days ago

Robert, yes, I think it should be the same as BigDecimal.new('200.0'). The problem arises, not when a programmer is typing the number---requiring a programmer to be explicit is OK by me---but when strings are processed that come from a user of the code.

ss = '200.' # Read from a user-prepared file.
BigDecimal.new(ss) => ArgumentError ...

As it is, the programmer has to massage every string to recognize a reasonable, albeit a bit sloppy, string that is clearly meant as a valid number.

Also, it seems crazy to me that

BigDecimal.new('200hello world') => 0.2e3

but BigDecimal('200.') raises an ArgumentError exception. Just sayin...

Regards,

#3 [ruby-core:82686] Updated by kernigh (George Koehler) 17 days ago

Float('200.') also raises ArgumentError. In this way, BigDecimal.new seems consistent with Float. But it's strange that Float('200hello world') raises ArgumentError but BigDecimal.new('200hello world') succeeds.

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