Why does `coerceAtLeast` has more priority then `-...

# announcements

[sikri]

Why does coerceAtLeast has more priority then -? -2.coerceAtLeast(0) == -2

[Michael de Kaste]

does val x = -string.length make sense?
functions and vals always have precedence over operators

[sikri]

- is not an operator, -2 is a signed int

[Michael de Kaste]

in many languages, in grammar, the - is simply seen as a negating operator, not part of the actual number.

[bezrukov]

yep, you can press control and highlight - . It will navigate you to unaryMinus even for val x = -2. You can use (-2).coerceAtLeast(0) == 0

[sikri]

I understand that this is the way it works, I just don’t understand why in the context of constant unsigned integer with sign on a left and with inline function on the right Kotlin gives more priority to inline function.

[Michael de Kaste]

because that's not how the grammar and tokenizer works. Making an exception to a literal where suddenly - does apply directly to the proceeding token shuffles up the grammar and compiler significantly.

[sikri]

string.length is an expression, it is not even a inlineable constant value. -2 is.
val a = -2 is NOT evalutated in runtime, it will look like BIPUSH -2
val b = -2.coerceAtLeast(0) looks like

INVOKESTATIC kotlin/ranges/RangesKt.coerceAtLeast (II)I  
INEG

[sikri]

i’m not writing any tokenizer or any parser, or any other language tool.
I just want to have a reasonable code without such side effects and for me it seems reasonable.
I don’t see anything criminal in else if combination, as it shows how nice to have mostly returning expressions

[Michael de Kaste]

maybe you should write your own parser to understand why this is done. can't explain it any other way

[sikri]

can you help me to understand why?
is there any major difference between 2.0, 2.someFunction() ?
Will this dot operator and minus sign be analyzed differently by parser and why not?
I would be glad to here just your two cents in order to google it myself
btw, maybe you know where does it lie in kotlin sources?

[bezrukov]

you can review 4th chapter Grammars and Parsing from kotlin language spec

Kotlin Language Specification ( PDFDrive.com ).pdf

[sikri]

thanks a lot, guys, for your comments and counterarguments, it definitely helped me to understand it
I will definitely check out more precisely spec

[bezrukov]

answering your question

is there any major difference between 2.0, 2.someFunction() ?

yes, there is a major difference here - 2.someFunction is decimal literal . identifier
(identifier must start with letter and underscore) while
2.0 is decimal literal . decimal literal

[bezrukov]

here is a note from the doc above exactly about your case:

4.2.3. Decimal Literals A decimal literal is a sequence of one or more ASCII decimal digits, followed by an optional L (LATIN CAPITAL LETTER L, U+004C). A literal without a suffix represents a constant value of type Int (TODO: it is more complicated). A literal with suffix L represents a constant value of type Long. A decimal literal represents a constant value that results from interpreting the literal in decimal notation. The value of a literal must lie within the range of its type. [Note: Decimal literals always represent non-negative integers. For example, an expression -5 is the unary operator minus applied to an operand that is a decimal literal 5, rather than a single decimal literal. End Note]

[sikri]

wow, even more thanks