From: Jamison Hope <jrh@theptrgroup.com>
To: "kawa@sourceware.org list" <kawa@sourceware.org>
Subject: Re: strange int->boolean behavior
Date: Fri, 20 Feb 2015 00:39:00 -0000 [thread overview]
Message-ID: <0D06BFFE-2807-4BA0-AAC3-5A999DA158B2@theptrgroup.com> (raw)
In-Reply-To: <54E66BD2.1060903@bothner.com>
On Feb 19, 2015, at 6:03 PM, Per Bothner <per@bothner.com> wrote:
> On 12/18/2014 10:19 AM, Jamison Hope wrote:
>> Sometimes, a primitive 0 is false:
>>
>> #|kawa:1|# (->boolean (->int 3))
>> Exception in thread "main" java.lang.Error: unsupported CodeAttr.emitConvert
>> at gnu.bytecode.CodeAttr.emitConvert(CodeAttr.java:2006)
>> [...]
>>
>> #|kawa:1|# (if (->int 3) "YES" "NO")
>> YES
>> #|kawa:2|# (if (->int 0) "YES" "NO")
>> YES
>> #|kawa:3|# (define (f x::int) ::string (if x "YES" "NO"))
>> #|kawa:4|# (f 3)
>> YES
>> #|kawa:5|# (f 0)
>> NO
>> #|kawa:6|# (disassemble f)
>> In class atInteractiveLevel$3
>>
>> Method name:"f" public static Signature: (int)java.lang.CharSequence
>> Attribute "Code", length:70, max_stack:1, max_locals:1, code_length:14
>> 0: iload_0
>> 1: ifeq 10
>> 4: getstatic <Field atInteractiveLevel$3.Lit0 java.lang.String>
>> 7: goto 13
>> 10: getstatic <Field atInteractiveLevel$3.Lit1 java.lang.String>
>> 13: areturn
>>
>> I get similar results with the other primitive types. If I'm following things correctly,
>> it's ConditionalTarget#compileFromStack which is treating zero as false?
>
> Yes. I checked in a fix for this. The change in ConditionalTarget depends on the language;
> specifically whether language.isTrue(Integer.valueOf(0)). If so, we an just
> emitGoto the true label.
Cool, thanks.
> I forgot about or overlooking this message, but found it while searching for
> another discussion
That's OK, I've been too busy lately to bug you about it (and you've obviously
been busy too, since you've made ~100 commits since then).
> (which turn out to be "proposed changes to handling of false
> and end-of-list").
>
> (I'm looking into doing at least part of that previous proposal - specifically
> treating #!null as false.)
Great! That will be a welcome change. Wow, that discussion was a while ago..
there's some good stuff in there (in my perhaps slightly biased opinion).
--
Jamison Hope
The PTR Group
www.theptrgroup.com
prev parent reply other threads:[~2015-02-20 0:39 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-12-18 18:19 Jamison Hope
2015-02-19 23:06 ` Per Bothner
2015-02-20 0:39 ` Jamison Hope [this message]
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