CODEWITHSUNDEEP
cbisonyacc
Simone
Simone

Reputation: 4940

Error: undeclared variable $

When I run the bisonprogram below (by bison file.y) , I get the error missing a declaration type for $2 in 'seq' :

%union {
       char cval;
}
%token <cval> AMINO 
%token STARTCODON STOPCODON

%%
series: STARTCODON seq STOPCODON {printf("%s", $2);}
seq : AMINO
         | seq AMINO
         ;
%%

I would like to know why I get this error, and how I can correctly declare the variable $2

Upvotes: 1

Views: 157

Answers (1)

Some programmer dude
Some programmer dude

Reputation: 409442

You haven't told Bison what type seq is, so it doesn't know what to do with $2.

Use the %type directive:

%type <cval> seq

Note that the type used for $2 is a single char, which is not a string as expected by the "%s" format. You need to come up with a way to create your own string from the sequence.

Upvotes: 2

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