Readme.md

   1 # evpf - postfix evaluator
   2
   3 evpf (**ev**aluate **p**ost**f**ix is a simple postfix expression evaluator
   4 written as a learning project in rust. It supports both command line and
   5 interactive mode.
   6
   7 ## Command line mode
   8
   9     evpf <expression>
  10
  11 where `<expression>` is a postfix expression like `20 30 + 11 -` etc.
  12 Currently only 4 operators are supported: `+`, `-`, `*` and `/`. (In command
  13 line mode, `*` has to be escaped using `\*` to work properly.)
  14
  15 ## Interactive mode
  16
  17 Interactive mode displays a prompt where expressions can be evaluated by
  18 typing into the prompt (line editing and command history support using
  19 `rustyline`).
  20
  21     evpf>
  22
  23 In interactive mode, apart from entering expressions, the following commands
  24 are supported
  25
  26 * `q` or `Q` - quit
  27 * `?` or `h` or `H` - help
  28