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#!/usr/bin/env lua
local table = require('table')
local readline = require('readline')
local utils = require('utils')
local types = require('types')
local reader = require('reader')
local printer = require('printer')
local List, Vector, HashMap = types.List, types.Vector, types.HashMap
-- read
function READ(str)
return reader.read_str(str)
end
-- eval
function eval_ast(ast, env)
if types._symbol_Q(ast) then
if env[ast.val] == nil then
types.throw("'"..ast.val.."' not found")
end
return env[ast.val]
elseif types._list_Q(ast) then
return List:new(utils.map(function(x) return EVAL(x,env) end,ast))
elseif types._vector_Q(ast) then
return Vector:new(utils.map(function(x) return EVAL(x,env) end,ast))
elseif types._hash_map_Q(ast) then
local new_hm = {}
for k,v in pairs(ast) do
new_hm[EVAL(k, env)] = EVAL(v, env)
end
return HashMap:new(new_hm)
else
return ast
end
end
function EVAL(ast, env)
--print("EVAL: "..printer._pr_str(ast,true))
if not types._list_Q(ast) then return eval_ast(ast, env) end
local args = eval_ast(ast, env)
local f = table.remove(args, 1)
return f(unpack(args))
end
-- print
function PRINT(exp)
return printer._pr_str(exp, true)
end
-- repl
local repl_env = {['+'] = function(a,b) return a+b end,
['-'] = function(a,b) return a-b end,
['*'] = function(a,b) return a*b end,
['/'] = function(a,b) return math.floor(a/b) end}
function rep(str)
return PRINT(EVAL(READ(str),repl_env))
end
if #arg > 0 and arg[1] == "--raw" then
readline.raw = true
end
while true do
line = readline.readline("user> ")
if not line then break end
xpcall(function()
print(rep(line))
end, function(exc)
if exc then
if types._malexception_Q(exc) then
exc = printer._pr_str(exc.val, true)
end
print("Error: " .. exc)
print(debug.traceback())
end
end)
end
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