crystal/env.cr

   1 require "./types"
   2 require "./error"
   3
   4 module Mal
   5
   6   class Env
   7     property data
   8
   9     def initialize(@outer)
  10       @data = {} of String => Mal::Type
  11     end
  12
  13     def initialize(@outer, binds, exprs : Array(Mal::Type))
  14       @data = {} of String => Mal::Type
  15
  16       eval_error "binds must be list or vector" unless binds.is_a? Array
  17
  18       # Note:
  19       # Array#zip() can't be used because overload resolution failed
  20       (0...binds.size).each do |idx|
  21         sym = binds[idx].unwrap
  22         eval_error "bind name must be symbol" unless sym.is_a? Mal::Symbol
  23
  24         if sym.str == "&"
  25           eval_error "missing variable parameter name" if binds.size == idx
  26           next_param = binds[idx+1].unwrap
  27           eval_error "bind name must be symbol" unless next_param.is_a? Mal::Symbol
  28           var_args = Mal::List.new
  29           exprs[idx..-1].each{|e| var_args << e} if idx < exprs.size
  30           @data[next_param.str] = Mal::Type.new var_args
  31           break
  32         end
  33
  34         @data[sym.str] = exprs[idx]
  35       end
  36     end
  37
  38     def set(key, value)
  39       @data[key] = value
  40     end
  41
  42     def find(key)
  43       return self if @data.has_key? key
  44
  45       o = @outer
  46       if o
  47         o.find key
  48       else
  49         nil
  50       end
  51     end
  52
  53     def get(key)
  54       e = find(key)
  55       eval_error "#{key} not found" unless e
  56       e.data[key]
  57     end
  58   end
  59
  60 end