Indent Parser in Lark

indent.nim

import nimpy, ./macros # the macros in the other GIST

assert(pyImport("sys").version_info.major.to(int) >= 3)

let
  lark = pyImport("lark")
  idt = pyImport("lark.indenter")
  tree_grammar = """
?start: _NL* tree
tree: NAME _NL [_INDENT tree+ _DEDENT]

%import common.CNAME -> NAME
%import common.WS_INLINE
%declare _INDENT _DEDENT
%ignore WS_INLINE

_NL: /(\r?\n[\t ]*)+/
"""

var indenter = pyInstance(idt.Indenter):
  var
    NL_type = "_NL"
    OPEN_PAREN_types = newSeq[string]()
    CLOSE_PAREN_types = newSeq[string]()
    INDENT_type = "_INDENT"
    DEDENT_type = "_DEDENT"
    tab_len = 8

let
  parser = lark.Lark(tree_grammar, parser="lalr", postlex=indenter)
  test_tree = """a
    b
    c
        d
        e
    f
        g
"""

echo(parser.parse(test_tree).pretty())