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Parsing > Parser > andP

andP -- parser conjunction

Synopsis

Usage:
r = andP(p,q,...)
Inputs:
- (p,q,...), a sequence of parsers (of type Parser)
Outputs:
- r, a parser, a parser that accepts as many tokens as p will accept, then as many as q will accept, and so on. The return value is the sequence of values returned by each of the input parsers.

Description

An abbreviation for andP(p,q) is p@q.

If one of the arguments is a string then constParser is used to convert it into a parser.

i1 : (constParser "abc" @ constParser "def" : charAnalyzer) "abcdef"

o1 = (abc, def)

o1 : Sequence

See also

constParser -- produce a parser that accepts a fixed string, one character at a time
Parser : Analyzer -- combine a parser with a lexical analyzer to make a complete system

Code

-- ../../../../Macaulay2/packages/Parsing.m2:114-122
Parser @ Parser := (p,q) -> new Parser from (
     c -> (
          if c =!= null then (
               if (p' := p c) =!= null 
               then p' @ q 
               else if (val1 := p null) =!= null then if (q' := q c) =!= null then (val2 -> (val1,val2)) % q'
               )
          else if (val1 = p null) =!= null and (val2 := q null) =!= null then (val1,val2)
          ))