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readline = require "./node_readline.coffee"
types = require "./types.coffee"
reader = require "./reader.coffee"
printer = require "./printer.coffee"
Env = require("./env.coffee").Env
core = require("./core.coffee")
# read
READ = (str) -> reader.read_str str
# eval
is_pair = (x) -> types._sequential_Q(x) && x.length > 0
quasiquote = (ast) ->
if !is_pair(ast) then [types._symbol('quote'), ast]
else if ast[0].name == 'unquote' then ast[1]
else if is_pair(ast[0]) && ast[0][0].name == 'splice-unquote'
[types._symbol('concat'), ast[0][1], quasiquote(ast[1..])]
else
[types._symbol('cons'), quasiquote(ast[0]), quasiquote(ast[1..])]
is_macro_call = (ast, env) ->
return types._list_Q(ast) && types._symbol_Q(ast[0]) &&
env.find(ast[0]) && env.get(ast[0]).__ismacro__
macroexpand = (ast, env) ->
while is_macro_call(ast, env)
ast = env.get(ast[0])(ast[1..]...)
ast
eval_ast = (ast, env) ->
if types._symbol_Q(ast) then env.get ast
else if types._list_Q(ast) then ast.map((a) -> EVAL(a, env))
else if types._vector_Q(ast)
types._vector(ast.map((a) -> EVAL(a, env))...)
else if types._hash_map_Q(ast)
new_hm = {}
new_hm[k] = EVAL(ast[k],env) for k,v of ast
new_hm
else ast
EVAL = (ast, env) ->
loop
#console.log "EVAL:", printer._pr_str ast
if !types._list_Q ast then return eval_ast ast, env
# apply list
ast = macroexpand ast, env
if !types._list_Q ast then return ast
[a0, a1, a2, a3] = ast
switch a0.name
when "def!"
return env.set(a1, EVAL(a2, env))
when "let*"
let_env = new Env(env)
for k,i in a1 when i %% 2 == 0
let_env.set(a1[i], EVAL(a1[i+1], let_env))
ast = a2
env = let_env
when "quote"
return a1
when "quasiquote"
ast = quasiquote(a1)
when "defmacro!"
f = EVAL(a2, env)
f.__ismacro__ = true
return env.set(a1, f)
when "macroexpand"
return macroexpand(a1, env)
when "try*"
try return EVAL(a1, env)
catch exc
if a2 && a2[0].name == "catch*"
if exc instanceof Error then exc = exc.message
return EVAL a2[2], new Env(env, [a2[1]], [exc])
else
throw exc
when "do"
eval_ast(ast[1..-2], env)
ast = ast[ast.length-1]
when "if"
cond = EVAL(a1, env)
if cond == null or cond == false
if a3? then ast = a3 else return null
else
ast = a2
when "fn*"
return types._function(EVAL, a2, env, a1)
else
[f, args...] = eval_ast ast, env
if types._function_Q(f)
ast = f.__ast__
env = f.__gen_env__(args)
else
return f(args...)
# print
PRINT = (exp) -> printer._pr_str exp, true
# repl
repl_env = new Env()
rep = (str) -> PRINT(EVAL(READ(str), repl_env))
# core.coffee: defined using CoffeeScript
repl_env.set types._symbol(k), v for k,v of core.ns
repl_env.set types._symbol('eval'), (ast) -> EVAL(ast, repl_env)
repl_env.set types._symbol('*ARGV*'), []
# core.mal: defined using the language itself
rep("(def! not (fn* (a) (if a false true)))");
rep("(def! load-file (fn* (f) (eval (read-string (str \"(do \" (slurp f) \")\")))))");
rep("(defmacro! cond (fn* (& xs) (if (> (count xs) 0) (list 'if (first xs) (if (> (count xs) 1) (nth xs 1) (throw \"odd number of forms to cond\")) (cons 'cond (rest (rest xs)))))))")
rep("(defmacro! or (fn* (& xs) (if (empty? xs) nil (if (= 1 (count xs)) (first xs) `(let* (or_FIXME ~(first xs)) (if or_FIXME or_FIXME (or ~@(rest xs))))))))")
if process? && process.argv.length > 2
repl_env.set types._symbol('*ARGV*'), process.argv[3..]
rep('(load-file "' + process.argv[2] + '")')
process.exit 0
# repl loop
while (line = readline.readline("user> ")) != null
continue if line == ""
try
console.log rep line
catch exc
continue if exc instanceof reader.BlankException
if exc.stack then console.log exc.stack
else console.log exc
# vim: ts=2:sw=2
|
