Orelang implementation using dart

about

implemented orelang with dart language.

c.f. https://qiita.com/Uchijo/items/4fd9849ac223b80d7615

usage

dart run 'some program here'

example

$ dart run bin/orelang_dart.dart '["+", 40, 2]'
result: 42

value types

• integer
• bool
• novalue
  • something like null or nil in other language.

supported features

• >, <, ==, +, *, and, or
  • [op, expression1, expression2]
  • operators.
• while
  • ["while", condition, expression]
  • evaluates expression while condition is true.
  • returns result of evaluation on last expression.
    • novalue is not counted as "last expression".
    • if there's no valid expression evaluation in while loop, it will return novalue.
• set
  • ["set", "identifier", expression]
  • variable named identifier will be initialized with value expression. overwrite is allowed.
  • returns evaluated value of expression
• get
  • ["get", "identifier"]
  • retrieves value of variable with the identifier.
• step
  • ["step", expression, ...]
  • evaluates all given expressions.
  • returns result of evaluation on last expression.
    • novalue is not counted as "last expression".
    • if there's no valid expression evaluation in steps, it will return novalue.
• if
  • ["if", cond, on_true, on_false]
• skip
  • ["skip"]
  • doees nothing.
  • returns novalue.