nondescript

Nondescript started as a nim implementation of clox (see https://craftinginterpreters.com) but has acquired large deviations.

Deviations from lox

• closures, gc not implemented yet

• classes will not be implemented

• Everything is an expression, except variable declarations and break statements

  • hence expressions can contain statements, so the stack is tracked inside the compiler, using compiler.stackCount
  • uses different local representation than lox inside the compiler
  • compiler.addLocal also has a delta argument - check it out if interested

• 1 file = 1 chunk

  • function objects are just a pointer to an instruction to jump to

• constant indexes, local indexes have 2 bytes as arguments - no 256 limit on locals/constants

• block expressions can be labelled (@label) and the break statement takes a label to break out of

• set block expression results using :label

• set the return value of functions using :result

• lists (example: @[1, 4, 5])

• tables (example: @{ "hello" = "world"})

• length operator #

• ampersand operator to chain binary operators to finished expressions

Examples

See the following folders in the source tree, look for the extension .nds:

• benchmarks/
• examples/
• tests/

Building

Requirements:

• nim (1.6.2 tested)
• c compiler (gcc, glibc tested)

The 4 steps to a REPL:

git clone https://github.com/prod2/nondescript
cd nondescript
nimble build
bin/nds