See "Análisis Sintáctico Predictivo Recursivo"
http://nereida.deioc.ull.es/~pl/perlexamples/node85.html
for a detailed description

Example for "Procesadores de Lenguajes"
Grado de Informática
Universidad de La Laguna

This project contains an example of an infix to postfix translator
for the 'simple assignment' language generated by the grammar below.
The translator conforms to the recursive predictive descendant technique.

assignment   : expression '=' assignment
             | expression
;
expression   : expression ADDOP term
             | term
;
term         : term MULOP factor
             | factor

factor       : NUMBER
             | ID
             | '(' assignment ')'
;

where:

ADDOP  = /^[-+]$/
MULOP  = %r{^[*/]$}
NUMBER = /^\d+$/
ID     = /[a-zA-Z_]\w*/