Assignment 4: Desiging LL(1) parser
Information table:
We have to design an LL(1) parser for:
E --> E+T
E --> E-T
E --> T
T --> T*F
T --> T/F
T --> F
F --> num
F --> id
F --> (E)
which can also be written as:
E --> E+T | E-T | T
T --> T*F | T/F | F
F --> num | id | (E)
However, the above the grammer is left recursive, so we first need to remove left recursions as follows:
E --> TX
X --> +TX | -TX | eps
T --> FY
Y --> *FY | /FY | eps
F --> num | id | (E)
Parsing table:
| num | id | ( | + | - | * | / | $ | |
|---|---|---|---|---|---|---|---|---|
| E | TX | TX | TX | |||||
| X | eps | +TX | -TX | eps | ||||
| T | FY | FY | FY | |||||
| Y | eps | eps | eps | *FY | /FY | eps | ||
| F | num | id | (E) |
Members and contributions
-
Shobhit Belwal (1901191)
- subroutine for making parse table
- code for checking if a string is accepted by the grammar
- removing left recursion
- Lex rule
-
Ujjwal Goel (1901209)
- subroutine for finding first set
- subroutine for finding follow set
- verifcation of parsing table
- code for removing left-recursion and left-factoring