Question

Is it possible to generate a parser for a scripting language that uses the Reverse Polish notation (and a Postscript-like syntax) using bison/yacc?

The parser should be able to parse code similar to the following one:

/fib
{
  dup dup 1 eq exch 0 eq or not
  {
    dup 1 sub fib
    exch 2 sub fib
    add
  } if
} def

Answer 1

Given the short description above and the notes on Wikipedia:
http://en.wikipedia.org/wiki/Stack-oriented_programming_language#PostScript_stacks

A simple bison grammer for the above could be:

%token          ADD
%token          DUP
%token          DEF
%token          EQ
%token          EXCH
%token          IF
%token          NOT
%token          OR
%token          SUB
%token          NUMBER
%token          IDENTIFIER

%%


program         :   action_list_opt
action_list_opt :   action_list
                |                           /* No Action */
action_list     :   action
                |   action_list action
action          :   param_list_opt operator
param_list_opt  :   param_list
                |                           /* No Parameters */
param_list      :   param
                |   param_list param
param           :   literal
                |   name
                |   action_block

operator        :   ADD
                |   DUP
                |   DEF
                |   EQ
                |   EXCH
                |   IF
                |   NOT
                |   OR
                |   SUB

literal         :   NUMBER
name            :   '/' IDENTIFIER
action_block    :   '{' program '}'


%%