Perl6 LTM Semantics

gistfile1.txt

L.T.M.P. = Longest Term Matching Prefix
P.P. = Partially procedural (the L.T.M.P. cannot extend beyond this construct)

L.T.M.P. will match the whole construct of anything which is not P.P. 


FOO BAR
	P.P. if either FOO or BAR are P.P.
	if FOO is not P.P. then the L.T.M.P is FOO followed by the L.T.M.P of BAR
	otherwise the L.T.M.P is the L.T.M.P of FOO

FOO | BAR

	P.P. if either FOO or BAR are P.P.
	L.T.M.P is the alternation of the L.T.M.P's of FOO and BAR

FOO & BAR

	P.P. if either FOO or BAR are P.P.
	L.T.M.P is the conjuction of the L.T.M.P's of FOO and BAR
		i.e. for a given target the L.T.M.P. is the shorter match
		against the L.T.M.P's of FOO and BAR

( FOO )
[ FOO ]
	P.P. if FOO is P.P.
	L.T.M.P. is the L.T.M.P. of FOO

{ CODE }
FOO || BAR
FOO && BAR
	P.P.
	L.T.M.P. is empty

	**** S05 disagrees **** P.P. and L.T.M.P. are the same as FOO for || and &&

FOO ~~ BAR
FOO !~~ BAR
	P.P.
	L.T.M.P. is the L.T.M.P. of FOO

FOO ~ BAR BAZ
	P.P. if any of FOO, BAR or BAZ are P.P.
	if neither FOO nor BAZ are P.P. then the L.T.M.P. is FOO followed by BAZ followed by the L.T.M.P. of BAR
	otherwise unless FOO is P.P. then the L.T.M.P is FOO followed by the L.T.M.P of BAZ
	otherwise the L.T.M.P is the L.T.M.P of FOO

FOO QUANTIFIER
FOO QUANTIFIER % SEP
	P.P. if FOO (or SEP) is P.P. or if QUANT is not greedy
	L.T.M.P is emtpy if QUANT is not greedy and has minimum repetitions of 0
	otherwise if SEP is P.P. but FOO isn't then the L.T.M.P. is FOO followed by the L.T.M.P of SEP
	otherwise the L.T.M.P is the L.T.M.P of FOO

	**** S05 DISAGREES *** eager (non-greedy) quantifiers are P.P. and always have an empty L.T.M.P.

::
:::
	P.P.
	L.T.M.P. is empty

<?>
<?FOO>
<!>
<!FOO>
	Not P.P.
	L.T.M.P is empty
	SPECIAL CASE - LTM does not have to worry about this for correctness as long as LTM backtracking
	works properly,  then any longest term which chooses this path but the assertion fails should
	just backtrack to the next longest term.

<SUBRULE>
<.SUBRULE>
	If a subrules definition is still P.P. while assuming all subrule calls within it are not,
	then the subrule invocation is P.P.
	Otherwise the subrule has a list of dependent subrules which if any are P.P. then the subrule
	invocation is also.
	L.T.M.P is the L.T.M.P of the subrule