Car Trialling

Time limit1sMemory limit128 MB

Summary

Parse each line against a small case-sensitive grammar and decide whether it is a valid car-trialling instruction, echoing it with spaced collapsed or printing Trap!.

Level: Medium6 of 10
Topics: String, Implementation, Recursion, Brute force
Solved: No attempts yet

Problem

Car trialling is a motorsport in which the driver must follow a set of very precisely worded instructions. When designing a trial, the organiser deliberately plants "traps" in the wording to catch out the unwary.

Write a program that decides whether an instruction obeys the rules below, which are loosely based on real car-trialling instructions.

The grammar uses the following notation:

Words in UPPERCASE (for example GO, KEEP, RIGHT) are literal text that must appear exactly as shown; matching is case sensitive.
Lowercase names are grammar rules.
| separates alternatives, exactly one of which must be chosen.
.. expands a range, so A..D means A | B | C | D.

instruction   = navigational | time-keeping | navigational AND time-keeping
navigational  = directional | navigational AND THEN directional
directional   = how direction | how direction where
how           = GO | GO when | KEEP
direction     = RIGHT | LEFT
when          = FIRST | SECOND | THIRD
where         = AT sign
sign          = "signwords"
signwords     = s-word | signwords s-word
s-word        = letter | s-word letter
letter        = A..Z | .
time-keeping  = record | change
record        = RECORD TIME
change        = cas TO nnn KMH
cas           = CHANGE AVERAGE SPEED | CAS
nnn           = digit | nnn digit
digit         = 0..9

s-word and nnn are sequences of letters and digits respectively, with no spaces inside them. Consecutive items are separated by one or more spaces, with three exceptions where there is no space at all: immediately before a period (.), immediately after an opening quotation mark ("), and immediately before a closing quotation mark (").

Input

The input consists of several instructions, one per line. Each line contains at most 75 characters. The input ends with a line containing a single #, which is not itself an instruction and must not be processed.

Output

For each instruction line, print one numbered line. Lines are numbered sequentially starting from 1.

Each output line starts with the line number, right-justified in a field of 3 characters, followed by a full stop (.) and a single space. After that:

if the instruction is valid, print the instruction itself, with every run of more than one space reduced to a single space;
otherwise, print Trap!.

Examples4

Example 1

Input

KEEP LEFT AND THEN GO RIGHT
CAS TO 20 KMH
GO FIRST       RIGHT AT "SMITH ST."  AND   CAS TO 20 KMH
GO 2nd RIGHT
GO LEFT AT "SMITH STREET AND RECORD TIME
KEEP RIGHT AND THEN RECORD TIME
#

Expected output

  1. KEEP LEFT AND THEN GO RIGHT
  2. CAS TO 20 KMH
  3. GO FIRST RIGHT AT "SMITH ST." AND CAS TO 20 KMH
  4. Trap!
  5. Trap!
  6. Trap!

Example 2
Input
```
GO RIGHT
#
```
Expected output
```
  1. GO RIGHT
```

Example 3

Input

KEEP LEFT
RECORD TIME
CHANGE AVERAGE SPEED TO 100 KMH
GO SECOND LEFT AT "A.B.C" AND RECORD TIME
#

Expected output

  1. KEEP LEFT
  2. RECORD TIME
  3. CHANGE AVERAGE SPEED TO 100 KMH
  4. GO SECOND LEFT AT "A.B.C" AND RECORD TIME

Example 4

Input

GO FIRST LEFT AT "N" AND THEN KEEP RIGHT AND THEN GO RIGHT AT "MAIN ST." AND CAS TO 5 KMH
#

Expected output

  1. GO FIRST LEFT AT "N" AND THEN KEEP RIGHT AND THEN GO RIGHT AT "MAIN ST." AND CAS TO 5 KMH