Isle

Isle is a scripting language inspired by Ruby, Lua, Python and Déjà Vu.

Requirements

Python 3.3+
pyparsing 2.0.3+

Usage

python3 -m isle yourfile.isl

Tell me about the language

Datatypes

nil, the only falsy value
Integers

Strings: "like this", """like this (can have internal newlines""",

  <<<identifier
  or like this
  this is a here-doc, starting
  with <<< and an identification string
  and ending in the identification string,
  followed by >>>
  identifier>>>

They are all different ways of writing the same thing (except here-docs doesn't do escaped character or interpolation)

Functions: do 42 end
Symbols: :like_this, :'or like this'. The latter way of writing is useful if the symbol isn't a valid identifier, like :'+'.
Tables: ("one", "two", three="four", ["five"]="six"). This is pretty much exactly taken from how tables work in Lua. Kind of like a combination of Python's list and dict.

Fun facts

All functions take one argument, which is a table literal, and return a single value, which can be anything. The argument will actually be used as the local environment in a function call! (do puts(value) end)(value=42) prints 42.
Tables can override binary and unary operators by having the corresponding symbol as a key in themselves: ('+'=do 7 end) + 1 == 7. You can use any of the existing operators, and you can define your own binary operators!
Any value can be used as a table key, but ints and symbols are special: they get their own syntax in table literals (([1] = :x, [:q] = 7) is the same as (:x, q = 7)), and value access (a[:foo] is the same as a.foo, and a[1] is the same as a.$1, and they are used to access the environment: foo for the key :foo and $1 for the key 1.
Non-positive integer names are special: $0 is the current function, $-1 is the current environment, $-2 is the environment of the directly enclosing function, $-3 the environment of the function enclosing that one, etc.
The standard library contains a function called apply, which takes a function and a table, which will be used as the environment. This can be used to simulate classes.
'()' is similar to __call__ and __call in Python and Lua respectively.
String interpolation is really useful: lie = "I am {myage() - 7} y/o". No formatting options are available, strings will be inserted as-is and other values are inserted equivalent to how they would be show with show().
Supported string escapes are \\, \n, \r, \t, \", \{, \} and finally \hexdigits; for Unicode code points. All other appearances of \ in string literals are illegal.

gvx / isle