fibin language

A simple functional language written using c++ templates.

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coauthor: @Pawel494

Semantics

• Literals Lit - only allowed Fibbonaci numbers (non negative): Fib<0> = 0, Fib<1> = 1 ... or logic values: True, False,
  example:

  Lit<Fib<0>>, Lit<True>
  

• Variables Var:

  Var(const char*)
  

  labels are string (1 to 6 signs) with letters (case insensitive) and digits,
  example:

  Var("A"), Var("01234"), Var("Cdefg")
  

• Arithmetic operations Sum, Inc1, Inc10

  • Sum<...> - multiple arguments sum (at least two),
  • Inc1<Arg> - adds Fib<1> to Arg,
  • Inc10<Arg> - adds Fib<10 to Arg,

  example:

  Sum<Lit<Fib<0>>, Lit<Fib<1>>, Lit<Fib<3>>>, Inc1<Lit<Fib<0>>>
  

• Comparison Eq - Eq<Left, Right> compares value of Left with Right,
  example:

  Eq<Lit<Fib<0>>, Lit<Fib<1>>>
  

• Refernce Ref - Ref<Var> return the value of Var,
  example:

  Ref<Var("A")>
  

• Expression Let - Let<Var, Value, Expression> assigns Value to the Var and calculates given Expression,
  example:

  Let<Var("A"), Lit<Fib<1>>, Ref<Var("A")>>
  

• Expression If - If<Condition, Then, Else> if Condition result is True then calculates value of Then otherwise value of Else is calculated, \ example:

  If<Lit<True>, Lit<Fib<1>>, Lit<Fib<0>>>
  

• Expression Lambda - Lambda<Var, Body> reprezents anonymous function with singe input argument Var and body Body,
  example:

  Lambda<Var("x"), Ref<Var("x")>>
  

• Function invocation Invoke - Invoke<Fun, Param> calculates Fun result for the given input parameter Param,
  example:

  Invoke<Lambda<Var("x"), Ref<Var("x")>>, Lit<Fib<0>>>