I'm trying to parse CCL commands like:

       dylan
       "bob dylan"
       dylan or zimmerman
       bob and (dylan or zimmerman)
[download]

I need to seach a database for each token and combine the results.

• What the best approach for this task?
• I've been looking at a lot of parsers, but can't find anything similar.
• I've found a grammar for such a comman, but failed to build any perl code from this

Any surgestions?

:-) Erik Bachmann

Examle grammar:

  CCL-Find ::= CCL-Find Op Elements
             | Elements.

  Op ::= "and" | "or" | "not"
  -- The above means that Elements are separated by boolean operators.

  Elements ::= '(' CCL-Find ')'
             | Set
             | Terms
             | Qualifiers Relation Terms
             | Qualifiers Relation '(' CCL-Find ')'
             | Qualifiers '=' string '-' string
  -- Elements is either a recursive definition, a result set reference
+, a
  -- list of terms, qualifiers followed by terms, qualifiers followed
  -- by a recursive definition or qualifiers in a range (lower - upper
+).

  Set ::= 'set' = string
  -- Reference to a result set

  Terms ::= Terms Prox Term
          | Term
  -- Proximity of terms.

  Term ::= Term string
         | string
  -- This basically means that a term may include a blank

  Qualifiers ::= Qualifiers ',' string
               | string
  -- Qualifiers is a list of strings separated by comma

  Relation ::= '=' | '>=' | '<=' | '<>' | '>' | '<'
  -- Relational operators. This really doesn't follow the ISO8777
  -- standard.

  Prox ::= '%' | '!'
  -- Proximity operator
[download]

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