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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 Env = require('env')
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
return env:get(ast)
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 a0,a1,a2 = ast[1], ast[2],ast[3]
local a0sym = types._symbol_Q(a0) and a0.val or ""
if 'def!' == a0sym then
return env:set(a1, EVAL(a2, env))
elseif 'let*' == a0sym then
local let_env = Env:new(env)
for i = 1,#a1,2 do
let_env:set(a1[i], EVAL(a1[i+1], let_env))
end
return EVAL(a2, let_env)
else
local args = eval_ast(ast, env)
local f = table.remove(args, 1)
return f(unpack(args))
end
end
-- print
function PRINT(exp)
return printer._pr_str(exp, true)
end
-- repl
local repl_env = Env:new()
function rep(str)
return PRINT(EVAL(READ(str),repl_env))
end
repl_env:set(types.Symbol:new('+'), function(a,b) return a+b end)
repl_env:set(types.Symbol:new('-'), function(a,b) return a-b end)
repl_env:set(types.Symbol:new('*'), function(a,b) return a*b end)
repl_env:set(types.Symbol:new('/'), function(a,b) return math.floor(a/b) 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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