Re: [Scheme-reports] grammar of numbers

[John Cowan <cowan@x>]

Michael Montague scripsit:

> The grammar of numbers on p. 62 appears to require that complex numbers 
> without a real part must have a sign on the imaginary part.

Yes, that's been true since R4RS.  (In R2RS and R3RS, complex numbers
without a real part were disallowed altogether.)

> For example, 100i must be written as +100i. Chibi happily accepts 100i 
> and treats it as 0+100i.
> 
> Is there an error in the grammar or is Chibi providing an extension?

It's an extension.  Of my current crop of test Schemes, only Chibi,
Vicare, and Kawa support unsigned imaginary numbers.  (RScheme supports
the syntax, but throws an exception saying that `make-rectangular`
is not implemented.)

-- 
I marvel at the creature: so secret and         John Cowan
so sly as he is, to come sporting in the pool   cowan@x
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