Descent Parser

LL1 parser with C

A small LL1 analyser that can remove recusrsion, calculate the first and follow of a given production rules then you can enter a word to analyse it.

how to use

syntax

• terminal must be lower case
• non-terminals must be upper case
• terminals and non-terminals should be one character at most
• epsilon are represented by the character '&'

install and run

gcc LL_1_parser.c -o LL1 
./LL1

exemple

remove recursion ,calculate first and follow

after running you can type the following production rules as an exemple :

E->E+T|T

T->T*F|F

F->(E)|d

.

when u finish typing your prodution rules you need to type '.' then press enter

• this is the result of the first step of the execution

analyse a given word

now we jump to next step wich is verifying a given word matching our production rules (grammar) or not. so we type this word for exemple: (d+d)*(d+d)

note: non-terminal characters must be the same as the non-terminals entred in the production rules.

for exemple the word (5+5)*5 will not be accepted despite it is correct instead you should type (d+d)*d

as we can see it tell's us that this word is accepted !.

sorry for the one file code 😕