next | previous | forward | backward | up | top | index | toc | home

Parsing > Parser > QQParser

QQParser -- a parser that accepts (and returns) a rational number, one character at a time

Description

The denominator must be present.

i1 : (QQParser : charAnalyzer) "-123456789/54321"

       41152263
o1 = - --------
         18107

o1 : QQ

See also

charAnalyzer -- a lexical analyzer that provides characters from a string one at a time
Parser : Analyzer -- combine a parser with a lexical analyzer to make a complete system

Code

-- Parsing.m2:90
Function % Parser := (fun,p) -> new Parser from ( c -> if (p' := p c) =!= null then if c === null then fun p' else fun % p' )
| symbol   class              value                                  location of symbol
| ------   -----              -----                                  ------------------    
| fun    : FunctionClosure -- {*Function[Parsing.m2:160:25-160:32]*} Parsing.m2:90:22-90:22
| p      : Parser          -- {*Function[Parsing.m2:98:54-110:83]*}  Parsing.m2:90:26-90:26