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update syntax-floats for changes to math.parser. clarify docs on hex float literals

db4
Joe Groff 2010-02-08 10:42:04 -08:00
parent 243a97e8dd
commit a8e771c28f
1 changed files with 39 additions and 6 deletions
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core/syntax/syntax-docs.factor
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@ -65,26 +65,59 @@ ARTICLE: "syntax-ratios" "Ratio syntax"
"More information on ratios can be found in " { $link "rationals" } ;
ARTICLE: "syntax-floats" "Float syntax"
"Floating point literals can be input in base 10 or 16. Base 10 literals must contain a decimal point, and may contain an exponent after " { $snippet "e" } ":"
"Floating point literals are specified when a literal number contains a decimal point or exponent. Exponents are marked by an " { $snippet "e" } " or " { $snippet "E" } ":"
{ $code
"10.5"
"-3.1456"
"7.e13"
"7e13"
"1.0e-5"
"1.0E+5"
}
"Base 16 literals use " { $snippet "p" } " instead of " { $snippet "e" } " for the exponent, which is still decimal:"
"Literal numbers without a decimal point or an exponent always parse as integers:"
{ $example
"10.125 HEX: 1.44p3 = ."
"1 float? ."
"f"
}
{ $example
"1. float? ."
"t"
}
"Syntax for special float values:"
{ $example
"1e0 float? ."
"t"
}
"Literal floating point approximations of ratios can also be input by placing a decimal point in the denominator:"
{ $example
"1/2. ."
"0.5"
}
{ $example
"1/3. ."
"0.3333333333333333"
}
"The special float values have their own syntax:"
{ $table
{ "Positive infinity" { $snippet "1/0." } }
{ "Negative infinity" { $snippet "-1/0." } }
{ "Not-a-number" { $snippet "0/0." } }
}
"A Not-a-number with an arbitrary payload can also be parsed in:"
"A Not-a-number literal with an arbitrary payload can also be input:"
{ $subsections POSTPONE: NAN: }
"Hexadecimal float literals are also supported. These consist of a hexadecimal literal with a decimal point and an optional base-two exponent expressed as a decimal number after " { $snippet "p" } " or " { $snippet "P" } ":"
{ $example
"8.0 HEX: 1.0p3 = ."
"t"
}
{ $example
"1024.0 HEX: 1.0P10 = ."
"t"
}
{ $example
"10.125 HEX: 1.44p3 = ."
"t"
}
"The normalized hex form " { $snippet "HEX: ±1.MMMMMMMMMMMMMp±EEEE" } " allows any floating-point number to be specified precisely. The values of MMMMMMMMMMMMM and EEEE map directly to the mantissa and exponent fields of IEEE 754 representation."
$nl
"More information on floats can be found in " { $link "floats" } "." ;
ARTICLE: "syntax-complex-numbers" "Complex number syntax"