[fpc-devel] new features and facilities

Mark Morgan Lloyd markMLl.fpc-devel at telemetry.co.uk
Fri Oct 9 11:20:07 CEST 2015

Michael Van Canneyt wrote:
> On Fri, 9 Oct 2015, Sven Barth wrote:
>> Am 08.10.2015 23:48 schrieb "Michael Van Canneyt" 
>> <michael at freepascal.org>:
>>> Actually, yes I think C's or Javascript's ternary is better suited.
>>> Let me explain. If I see
>>> If expr1 then expr2 else expr3
>>> it says 'statement' to me. But
>>> a ? b : c;
>>> Says "expression" to me.
>>> So
>>> left := a ? b : c;
>> That's probably only because other languages use that as the ternary.
> No, it is because there are no keywords involved.
> The keyword "If" starts a statement. It's a simple rule.
> As I said: by using "if" in an expression, you break the rule and 
> introduce ambiguity.
>> There also another reason why I prefer the variant with the if: ease to
>> implement in the compiler.
>> For the if one merely needs to add a corresponding case in factor() while
>> for the ?: one needs to fiddle with the compiler's operator precedence
>> rules that are applied in sub_expr() which can lead to desaster either
>> during implementation or later on when bugs are discovered...
> I don't see how the use of "if" differs from "?" in rules of precedence, 
> they are at the exact same level.
> They're both just tokens to the compiler. At least "?" has the advantage 
> of being new and not yet used, so is unambiguously.

Jonas, what's your take on this as an overall language guru?

Mark Morgan Lloyd
markMLl .AT. telemetry.co .DOT. uk

[Opinions above are the author's, not those of his employers or colleagues]

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