> On 18 Sep 2018, at 16:45, Sven Van Caekenberghe <[email protected]> wrote:
>
> Of course, we could also extend the basic number parser and allow the native
> (stored) notation
>
> 1/3
> 3/2s2
>
> Note how that last one should use the more exact #storeOn: notation, not the
> #printOn:
>
> I'll have to think about this a bit more, as I can really not choose right
> now.
I am still not sure if we should do this or not, but here is a POC
implementation of the above.
It implements the following syntax extension (see the class comment of STON for
the rest).
number
int
int denominator
int denominator scale
int frac
int exp
int frac exp
denominator
/ digits
scale
s digits
STONWriter>>#writeFraction: fraction
jsonMode
ifTrue: [ self writeFloat: fraction asFloat ]
ifFalse: [
writeStream
print: fraction numerator;
nextPut: $/;
print: fraction denominator ]
STONWriter>>#writeScaledDecimal: scaledDecimal
jsonMode
ifTrue: [ self writeFloat: scaledDecimal asFloat ]
ifFalse: [
writeStream
print: scaledDecimal numerator;
nextPut: $/;
print: scaledDecimal denominator;
nextPut: $s;
print: scaledDecimal scale ]
Fraction>>#stonOn: stonWriter
stonWriter writeFraction: self
ScaledDecimal>>#stonOn: stonWriter
stonWriter writeScaledDecimal: self
STONReader>>parseNumber
| negated number |
negated := readStream peekFor: $-.
number := self parseNumberInteger.
(readStream peekFor: $/)
ifTrue: [
number := Fraction numerator: number denominator: self
parseNumberInteger.
(readStream peekFor: $s)
ifTrue: [ number := ScaledDecimal
newFromNumber: number scale: self parseNumberInteger ] ]
ifFalse: [
(readStream peekFor: $.)
ifTrue: [ number := number + self
parseNumberFraction ].
((readStream peekFor: $e) or: [ readStream peekFor: $E
])
ifTrue: [ number := number * self
parseNumberExponent ] ].
negated
ifTrue: [ number := number negated ].
self consumeWhitespace.
^ number
Sven
