5e is not a valid float but parsed

[egao1980]

CL-USER> (parse-float:parse-float "5e")
5.0
2 (2 bits, #x2, #o2, #b10)

[ikrabbe]

Is it a bug or is it a feature?

[egao1980]

It's a bug as exponent should be present if 'e' is specified.

[ikrabbe]

I find it hard to think of an input parser that has problems because a easily guessable default value is missing. In this case the default is 0 of course.

[egao1980]

My point is that 0 is not the default here. Exponent is mandatory after 'e'. It is so in CL and many other languages.

[adlai]

CLHS 2.3.1 Numbers as Tokens

[egao1980]

yep, see the {digit}+ in exponent part:

exponent       ::=  exponent-marker
				   [sign]
				   {digit}+