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require_relative "mal_readline"
require_relative "types"
require_relative "reader"
require_relative "printer"
require_relative "env"
# read
def READ(str)
return read_str(str)
end
# eval
def eval_ast(ast, env)
return case ast
when Symbol
env.get(ast)
when List
List.new ast.map{|a| EVAL(a, env)}
when Vector
Vector.new ast.map{|a| EVAL(a, env)}
when Hash
new_hm = {}
ast.each{|k,v| new_hm[EVAL(k,env)] = EVAL(v, env)}
new_hm
else
ast
end
end
def EVAL(ast, env)
#puts "EVAL: #{_pr_str(ast, true)}"
if not ast.is_a? List
return eval_ast(ast, env)
end
# apply list
a0,a1,a2,a3 = ast
case a0
when :def!
return env.set(a1, EVAL(a2, env))
when :"let*"
let_env = Env.new(env)
a1.each_slice(2) do |a,e|
let_env.set(a, EVAL(e, let_env))
end
return EVAL(a2, let_env)
else
el = eval_ast(ast, env)
f = el[0]
return f[*el.drop(1)]
end
end
# print
def PRINT(exp)
return _pr_str(exp, true)
end
# repl
repl_env = Env.new
REP = lambda {|str| PRINT(EVAL(READ(str), repl_env)) }
repl_env.set(:+, lambda {|a,b| a + b})
repl_env.set(:-, lambda {|a,b| a - b})
repl_env.set(:*, lambda {|a,b| a * b})
repl_env.set(:/, lambda {|a,b| a / b})
# repl loop
while line = _readline("user> ")
begin
puts REP[line]
rescue Exception => e
puts "Error: #{e}"
puts "\t#{e.backtrace.join("\n\t")}"
end
end
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