Re: AST must for xlator?

"Russ Ramsey" <rramsey500NOSPAM@earthlink.net> writes:
> I wrote Lex & Yacc code to parse SAS; now how do I output the
> symbols into COBOL?
> ...
> Any examples out there of the simplest data structure for this purpose?


I have found that using a C library for building linked lists of typed
strings works well for translating output from Lex & Yacc. The %type
of all of your grammatical constructs is of the String type. You
ultimately output the translation by calling PrintString() in your
input production:


input:
        CompilationUnit { PrintString($1); }


CompilationUnit: /* empty */ { $$ = MAKE_EMPTY_STRING(); }
    | TypeDeclaration TypeDeclarations { $$ = OUTPUT($1); APPEND($$, $2); }
;


$1 after the parse contains any number of strings strung into a linked list.
The PrintString function is free to reinterpret the string-of-strings,
making multiple passes over it if necessary, and rewriting parts of it.


Cheers,
    James

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