stack-calculator

About

CLI evaluator for postfix expressions (reverse Polish notation)

Use

Download the release and execute it in the following form

./stack-calc [--stack] [file.json...]

• --stack

  If enabled, displays the stack after every operation

• file.json...

  Expand command list with json files

  ex:

  {
  "abs":"dup 0 < if -1 * noop",
  "dup":"1 pick",
  "err":"2 pick - abs swap /"
  }
  

Commands

• quit: quits the program
• help: displays commands list
• stack: displays the stack
• noop: pass
• clear: empties stack
• pop: removes top of stack
• popn: removes top n elements of the stack (ex: 1 2 3 2 popn => 1)
• skip: skips next n commands (ex: 2 skip 1 2 3 4 => 3 4)
• pick: copies the nth element of the stack (ex: 2 3 4 2 pick => 2 3 4 3)
• swap: swaps top 2 elements of the stack
• if: if the top element of the stack is 0, skip the next 3 commands (ex: 0 if 1 2 3 4 => 4)
• >, =, <: 1 if true, 0 otherwise (ex: 2 < 3 => 1)
• +, -, *, /, //, %, ^, e, pi, ln, sin, arcsin, cos, arccos, tan, arctan: standard functions

Custom Commands

In the form : command corresponding-commands... ;

• ex: : dup 1 pick ;