Grammar specification

yacv expects a context free grammar $G = (V, T, P, S)$

Here,

yacv expects a text file with list of productions. Each production $A \rightarrow B$ such that $A \in V$, $B \in (V+T)^*$ should be written as :

A -> B

Important notes :

Each symbol in $B$ must be separated by a whitespace
The grammar file is expected to contain only the list of productions
yacv will assume all the symbols that appear on the LHS of the production to be nonterminals
Any symbol that is not a nonterminal will be considered as a terminal
LHS of the very first production in grammar file will be assumed as starting symbol
To indicate $\epsilon$, '' must be used. Therefore, production $S \rightarrow \epsilon$ must be written as S -> ''
Symbol $ is reserved as an end of string and must not occur anywhere in the grammar file
Symbol S' is reserved for the augmented production [$S' \rightarrow S$ $]. This augmented production is automatically added by the parser so you need not add it yourself

Example CFG	CFG in `yacv` readable format
$$ S \rightarrow a S b \;\|\; \epsilon $$	S -> a S b S -> ''
$$ \begin{aligned} STMT &\rightarrow \verb+if+ \; STMT \; \verb+else+ \; STMT \\ & \|\; \verb+if+ \; STMT \;\|\; a \;\|\; b \;\|\; c \;\|\; d \end{aligned} $$	STMT -> if STMT else STMT STMT -> if STMT STMT -> a STMT -> b STMT -> c STMT -> d
$$ \begin{aligned} E &\rightarrow E + T \;\|\; E - T \;\|\; T\\ T &\rightarrow T * F \;\|\; T / F \;\|\; F\\ F &\rightarrow ( E ) \;\|\; id \end{aligned} $$	E -> E + T E -> E - T E -> T T -> T * F T -> T / F T -> F F -> ( E ) F -> id