%{ my $is_range = 0; %} %conflict rangeORenum { if ($is_range) { $self->YYSetReduce([',', ')'], 'ID:RANGE' ); } else { $self->YYSetReduce([',', ')'], 'ID:ENUM' ); } } %token ID = /([A-Za-z]\w*)/ %token NUM = /(\d+)/ %left ',' %left '-' '+' %left '*' '/' %expect-rr 2 %% type_decl : 'type' ID '=' type ';' expr ; type : %name ENUM Lookahead '(' id_list ')' | %name RANGE Lookahead expr '..' expr ; Lookahead: /* empty */ { $is_range = $_[0]->YYPreParse('Range'); } ; id_list : %name ID:ENUM ID %PREC rangeORenum | id_list ',' ID ; expr : '(' expr ')' { $_[2] } /* bypass */ | %name PLUS expr '+' expr | %name MINUS expr '-' expr | %name TIMES expr '*' expr | %name DIV expr '/' expr | %name COMMA expr ',' expr | %name ID:RANGE ID %PREC rangeORenum | %name NUM NUM ; %% =head1 SYNOPSIS See =over 2 =item * File C. =item * File C. =item * File pascalenumeratedvsrange.eyp in examples/debuggintut/ =item * The Bison manual L =back Compile it with: eyapp Range.eyp eyapp -TC pascalnestedeyapp2.eyp Run it with this options: $ ./pascalnestedeyapp2.pm -t -i -m 1 -c 'type e = (x, y, z);' $ ./pascalnestedeyapp2.pm -t -i -m 1 -c 'type e = (x, @, z);' Try also these inputs: type e = (x) .. (y); type r = (x) .. y ; type r = (x+2)*3 .. y/2 ; type e = (x, y, z); type e = (x); type e = (x, y, z) .. (u+v); =cut