Character-Level Regular Expression CPSL cannot specify character-level regular expressions that span multiple tokens.

(b) Example operations supported in AQL that cannot be expressed in expanded code-free CPSL grammars include (i) character-level regular expressions spanning multiple tokens, (ii) counting the number of annotations occurring within a given bounded window and (iii) deleting annotations if they overlap with other annotations starting later in the document.

Figure 3: Regular Expression Extraction Operator

3 illustrates the regular expression extraction operator in the algebra, which performs character-level regular expression matching.

0 The Extract operator (5) performs character-level operations such as regular expression and dictionary matching over text, creating a tuple for each match.