/* gram.y - yacc grammar for rail program */ %{ #include #ifdef _DCC #include #endif #include "rail.h" char optchar; %} /* identifier */ %token IDENTIFIER /* number */ %token NUMBER /* [annotation] */ %token ANNOT /* \rail@i \rail@p \rail@t \\ */ %token RAILI RAILP RAILT RAILCR /* TeX control sequence */ %token CS /* 'c' "string" */ %token STRING %type rule rules %type body body0 body1 body2e body2 body3 body4e body4 empty %type annot %start rails %% rails : rails rail | rail ; rail : RAILI raili | RAILP railp | RAILT railt | error ; railp : '{' { fprintf(outf,"\\rail@p {"); copy=1; optchar = '-'; } options '}' { fprintf(outf,"\n"); copy=0; } ; options : /*empty*/ | options '-' { optchar = '-'; } | options '+' { optchar = '+'; } | options IDENTIFIER { if(setopt(optchar,$2->name)==0) error("unknown option",(char *)NULL); if($2->kind==UNKNOWN) delete($2); } ; railt : '{' IDENTIFIER '}' { if($2->kind==UNKNOWN || $2->kind==TOKEN) $2->kind=TERM; else redef($2); fprintf(outf,"\\rail@t {%s}\n",$2->name); } ; raili : '{' NUMBER '}' { fprintf(outf,"\\rail@i {%d}",$2); copy=1; } '{' rules '}' { copy=0; fprintf(outf,"\n"); fprintf(outf,"\\rail@o {%d}{\n",$2); outrule($6); /* embedded action is $4 */ freerule($6); fprintf(outf,"}\n"); } ; rules : rules ';' rule { $$=addrule($1,$3); } | rules ';' { $$=$1; } | rule | error { $$=NULL; } ; rule : IDENTIFIER ':' { errorid=$1; } body { if($1->kind==UNKNOWN || $1->kind==TOKEN) $1->kind=NTERM; else redef($1); $$=newrule($1,$4); /* embedded action is $3 */ errorid=NULL; } | body { anonymous++; $$=newrule((IDTYPE *)NULL,$1); } ; body : body0 { $$=$1; $$->done=1; } ; body0 : body0 '|' ANNOT body1 { $$=newbody(ANNOTE,NULLBODY,NULLBODY); $$->text=$3; $$=addbody(CAT,$$,$4); $$=addbody(BAR,$1,$$); } | body0 '|' body1 { $$=addbody(BAR,$1,$3); } | ANNOT body1 { $$=newbody(ANNOTE,NULLBODY,NULLBODY); $$->text=$1; $$=addbody(CAT,$$,$2); } | body1 ; body1 : body2 '*' body4e { if(altstar && isemptybody($3)) { $$=newbody(EMPTY,NULLBODY,NULLBODY); $$=addbody(PLUS,$$,revbody($1)); } else { $$=newbody(EMPTY,NULLBODY,NULLBODY); $$=addbody(BAR,$$,addbody(PLUS,$1,revbody($3))); } } | body2 '+' body4e { $$=newbody(PLUS,$1,revbody($3)); } | body2e ; body2e : body2 | empty ; body2 : body2 body3 { $$=addbody(CAT,$1,$2); } | body3 ; body3 : body4 '?' { $$=addbody(BAR,newbody(EMPTY,NULLBODY,NULLBODY),$1); } | body4 ; body4e : body4 | empty ; body4 : '(' body0 ')' { $$=$2; $$->done=1; } | STRING annot { $$=newbody(STRNG,NULLBODY,NULLBODY); $$->annot=$2; $$->text=$1; } | IDENTIFIER annot { if($1->kind==UNKNOWN) $1->kind=TOKEN; $$=newbody(IDENT,NULLBODY,NULLBODY); $$->annot=$2; $$->id=$1; } | RAILCR { $$=newbody(CR,NULLBODY,NULLBODY); } ; empty : /*empty*/ { $$=newbody(EMPTY,NULLBODY,NULLBODY); } ; annot : ANNOT { $$=$1; } | /*empty*/ { $$=NULL; } ; %%