1-Give me the length of the Kenedy.
        spelling ->KENNEDY
PARSED!
Give the length of the ship KENNEDY JF 
LEN - 1072

2-Width and draft
PARSED!
Trying Ellipsis:  GIVE ME WIDTH AND DRAFT OF THE KENEDY
Give the beam and draft of the ship KENNEDY JF
(BEAM 130 DFT 36)

3-Who is her commander?
PARSED!
Give the rank and name of the commander of the ship KENNEDY JF
(RANK CAPT  NAME MOFFETT P)

4-What about the Fox?
PARSED!
Trying Ellipsis on:  THE FOX WHO IS THE FOX COMMANDER
Give the rank and name of the commander of the ship FOX
(RANK CAPT  NAME EVERETT J)

5-What U.S. merchant ships carrying vanadium ore are within 500 miles of the
Kimlow?
PARSED!
Give the position of and time at position for the ship
KIMLOW T
Give the name of merchant American ship S
        where the type of cargo on S is VNAD
        the great-circle distance from the position of S to 15-33N, 30-10W,
is          less than or equal to 500
SHIP = GREENVILLE VICTOR, CRAIN ME, TOTOR

6-How fast are the U.S. subs with lengths greater than 150 feet?
PARSED!
Give the maximum cruising speed for and name of American ship S
        where the first character of the type of S is S
        the second character of the type S is S
        the length of S is greater than 150
(A long table relating the names and maximum cruising speeds of American
submarines is printed.)

7-What French ships are at readiness status 1?
PARSED!
Give the name of French ship S
        where the state of readiness of S is 1
There is no French ship S
NONE


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LADDER uses a systemic (or semantic) grammar.  
You could parse some of the sentences with the following grammar rule:

q --> q-word,[me], ship-prop, ship-name.

Where q is a question sentence,
q-word is a question word, ship-prop is a ship property and ship-name is
the name of a ship.

----------------------------------------------------------------------


wh_s(Wh,N)   --> wh(Wh),[is],np(N).
np(N)        --> det, n(N).
det          --> [the].
n(kennedy)   --> [kennedy].

wh(where)    --> [where].

parse(S)     :-  wh_s(S,[],Wh,N), synonym(Wh,Wh_sum),
                 database(Wh_sym,N,Ans), write(Ans), nl.

synonym(where,locations).
database(location,kennedy,pacific).

/* following just show using {} */
wh(what     --> [what], {write(in_what), nl}.