JLS question regarding Text Blocks
james.laskey at oracle.com
Tue Apr 7 00:42:09 UTC 2020
The spec is correct as-is. I have been made aware that white space in spec terms, as well as the compiler, is only space, tab and form-feed. Other white space (such as non-breaking space, em space, ...) is illegal and produces a javac error.
> On Apr 6, 2020, at 8:46 PM, Dan Smith <daniel.smith at oracle.com> wrote:
>> On Apr 6, 2020, at 12:43 PM, Jim Laskey <james.laskey at oracle.com> wrote:
>> In section 3.10.6 Text Blocks of the updated spec;
>> "The opening delimiter is a sequence that starts with three double quote characters ("""), continues with zero or more space, tab, and form feed characters, and concludes with a line terminator."
>> However, the JEP 378 description reads "The opening delimiter is a sequence of three double quote characters (""") followed by zero or more white spaces followed by a line terminator.
>> javac uses the Character.isWhitespace test for characters following the opening three double quote characters.
>> Shouldn't the spec read as;
>> "The opening delimiter is a sequence that starts with three double quote characters ("""), continues with zero or more white space characters (Ex. space, tab, and form feed), and concludes with a line terminator."?
> Is there a question about semantics here, or just a question of how best to present it?
> Right now, TextBlockWhiteSpace defines precisely which characters can appear. Per 3.6, WhiteSpace is a grammar production that consists of 3 specific characters (space, horizontal tab, and form feed), plus the line terminators. TextBlockWhiteSpace excludes the line terminators.
> Given this, I don't think redirecting through an abstract notion of "white space" or the "Character.isWhitespace" API would be helpful—the grammar has already nailed it down to exactly three characters.
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