Common Text Transformation Library http://cttl.sourceforge.net/

Quote evaluation rules

1. If RL, RM, and RR represent opening, interior, and closing syntactic units of a quote

   
       quote( RL, RM, RR )
   
   

   then input symbols, corresponding to RL and RR sides, must be balanced, in order for the quote evaluation algorithm to succeed.

2. Quote implements repeatable balanced search algorithm, alternating repeatable search evaluation between the expressions RL and RR.

3. To keep the search for left and right symbols in balance,

   • If input contains nested pairs of symbols that match RL and RR, respectively, both expressions can be evaluated multiple times;

   • Expressions RL and RR are evaluated equal number of times;

   • Evaluation stops when the balance between the two sides is reached.

4. The parseable substring, visible by syntactic unit RM, represents the interior of the quote. As such, the interior substring is limited to the inner boundaries of the tokens matching RL and RR.

5. The expression RM is evaluated only once. If balance between left and right expressions is never found, the evaluation of the quote fails, and the expression RM is never evaluated.

6. Middle expression RM is not required to consume the entire parseable substring. As such, the expression RM is ungreedy. In order to complete successful evaluation of the quote grammar, it is sufficient for RM to match only the beginning part of the interior substring.

7. The RM expression is evaluated by match evaluation algorithm. Failed RM result causes the quote evaluation to fail, as well.

    

Copyright © 1997-2009 Igor Kholodov mailto:cttl@users.sourceforge.net.

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