Reads a flag token and sets or unsets the corresponding entry in the special FLAGS list.

Adds all characters from character FROM to character TO (inclusive) to the charset SET. Does the right thing with respect to case-(in)sensitivity as specified by the special variable FLAGS.

Combines all items in LIST into one charset and returns it. Items can be single characters, character ranges like (:RANGE #\A #\E), or special character classes like :DIGIT-CLASS. Does the right thing with respect to case-(in)sensitivity as specified by the special variable FLAGS.

Splits a REPETITION object into a constant and a varying part if applicable, i.e. something like a{3,} -> a{3}a* The arguments to this function correspond to the REPETITION slots of the same name.

Accumulate STR into the special variable STARTS-WITH if ACCUMULATE-START-P (also special) is true and STARTS-WITH is either NIL or a STR object of the same case mode. Always returns NIL.

Converts the parse tree PARSE-TREE into a REGEX object and returns it.

Will also

• split and optimize repetitions,

• accumulate strings or EVERYTHING objects into the special variable STARTS-WITH,

• keep track of all registers seen in the special variable REG-NUM,

• keep track of all named registers seen in the special variable REG-NAMES

• keep track of the highest backreference seen in the special variable MAX-BACK-REF,

• maintain and adher to the currently applicable modifiers in the special variable FLAGS, and

• maybe even wash your car...

Converts the parse tree PARSE-TREE into an equivalent REGEX object and returns three values: the REGEX object, the number of registers seen and an object the regex starts with which is either a STR object or an EVERYTHING object (if the regex starts with something like ".*") or NIL.

Accessor macro to extract the first flag out of a three-element flag list.

Accessor macro to extract the second flag out of a three-element flag list.

Accessor macro to extract the third flag out of a three-element flag list.