Please help me with the coding for LL(1)!! The given grammar was: P PL | L L N;
ID: 3840078 • Letter: P
Question
Please help me with the coding for LL(1)!!
The given grammar was:
P PL | L
L N; | M; | C
N print E
M print "W"
W TW |
C if E {P} | if E {P} else {P}
E (EOE) | V (note: this has a variable O)
O + | - | * V 0 | 1 | 2 | 3 (note: this has a terminal 0 (zero))
T a | b | c | d
And the grammar transformed in LL(1) is:
5.1 Parsing strings with an LL(1) table driven parser
Implement a program which parses strings using an LL(1) table driven parser using the table you determined for G in the previous exercise.
You may use Python, Java, C, C++, or Haskell. If you’d like to use a different language then please check with us first.
• Input: The first command line argument is the filename of a file containing the string of characters to test.
• Output: 1. Print a trace of the execution, showing the steps followed by the program as it performs the left-most derivation. This should look similar to parsing the string through a PDA. An example of this is given in the appendices.
2. After parsing the whole input file, print ACCEPTED or REJECTED, depending on whether or not the string could be derived by the grammar.
3. If there is a symbol in the input string which is not a terminal from the grammar, the program should output ERROR_INVALID_SYMBOL (This could be during or before trying to parse the input.) Note: all whitespace in the input file should be ignored (line breaks, spaces, etc.) The output will be easier to read if you remove the whitespace before starting the parse. Examples of the program output syntax are provided in the appendices.
5.2 Evaluating programs written in G
If a second command line argument “eval” is given, then instead of printing the trace of the parse, your program should:
1. Build a parse tree as it performs the leftmost derivation
2. Evaluate that parse tree. The semantics (meaning) which we are applying to our rules are as follows:
• V variables derive integers • W variables derive strings • E expressions are evaluated like normal integer arithmetic
• print E statements output (to screen) the result of evaluating the expression E. (i.e. print (1+1) outputs 2)
• print "W" statements output the string derived from W (i.e. print "abba" outputs abba)
• if statements evaluate the contents of their if block if and only if the condition evaluated to a non-zero value, otherwise the else block is evaluated instead (if there is one). If the input could not be parsed then output REJECTED instead. Some examples of programs and their expected output are provided in the appendices.
1. T all clad V 0 1 2 3 E CEOE) C' else (P) E 8, N' print M 10, L N IC 12.Explanation / Answer
Join long and dull successions of summons into a solitary, straightforward charge.
Sum up an arrangement of operations on one arrangement of information, into a methodology that can be connected to any comparative arrangement of information.
(e.g. apply a similar investigation to each information document on a CD, without expecting to rehash the orders)
Make new charges utilizing mixes of utilities in ways the first creators never considered.
Basic shell scripts may be composed as shell false names, however the script can be made accessible to all clients and all procedures. Shell pseudonyms apply just to the present shell.
Wrap programs over which you have no control inside a situation that you can control.
e.g. set condition factors, change to a unique index, make or select a design record, divert yield, log use, and after that run the program.
Make redid datasets on the fly, and call applications (e.g. matlab, sas, idl, gnuplot) to take a shot at them, or make redid application charges/techniques.
Fast prototyping (however abstain from giving models a chance to wind up generation)
Commonplace employments
Framework boot scripts (/and so forth/init.d)
Framework chairmen, for mechanizing numerous parts of PC support, client account creation and so forth.
Application bundle establishment instruments
Different instruments may make fancier installers (e.g. tcl/tk), yet can not be thought to be introduced as of now. Shell scripts are utilized in light of the fact that they are extremely convenient. Some product accompanies an entire establishment of the apparatus it needs to utilize (tcl/tk/python) keeping in mind the end goal to act naturally contained, however this prompts programming bloat.
Application startup scripts, particularly unattended applications (e.g. begun from cron or at)
Any client expecting to robotize the way toward setting up and running business applications, or their own particular code.