CODEWITHSUNDEEP
bisonyaccuntyped-variables
user2965337
user2965337

Reputation: 73

Byacc $$ is untyped, how to resolve

I am using byacc to construct a grammar, but when i want to use yyerrok it says to me byacc: e - line 44 of "bee.y", $$ is untyped

    definition:
      | error ';'               {$$ = 0; yyerrok; } 
      | definition ID defFirst ';'      
      | definition ID '(' defSecond ')' stmt
      ;

how do i solve the problem?

Upvotes: 2

Views: 2236

Answers (1)

Brian Tompsett - 汤莱恩
Brian Tompsett - 汤莱恩

Reputation: 5893

(Comments converted to an answer)

@Grzes wrote:

You get this message not because of yyerrok usage. The reason is $$ = 0;, i.e. you do not assign a type to the non-terminal definition (as @templatetypedef has said). With each production you can associate an action. Each action may return some semantic value which can be used in "higher" production. Moreover you can (or should) specify type of semantic value for each non-terminal and terminal. Take a look at bison doc: www.gnu.org/software/bison/manual/bison.html , especially pay attention to semantic value and semantic action.

Upvotes: 2

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