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mirror of https://github.com/kanaka/mal.git synced 2024-11-11 00:52:44 +03:00
mal/rexx/step9_try.rexx
2019-02-21 09:54:08 +00:00

288 lines
8.9 KiB
Rexx

/* Save command-line arguments from the top-level program before entering a procedure */
command_line_args. = ""
command_line_args.0 = arg()
do i=1 to command_line_args.0
command_line_args.i = arg(i)
end
call main
exit
#include "readline.rexx"
#include "reader.rexx"
#include "printer.rexx"
#include "types.rexx"
#include "env.rexx"
#include "core.rexx"
read: procedure expose values. err /* read(str) */
return read_str(arg(1))
pair?: procedure expose values. /* pair?(ast) */
ast = arg(1)
return sequential?(ast) & words(obj_val(ast)) > 0
quasiquote: procedure expose values. env. err /* quasiquote(ast) */
ast = arg(1)
if \pair?(ast) then return new_list(new_symbol("quote") || " " || ast)
ast0 = word(obj_val(ast), 1)
if symbol?(ast0) & obj_val(ast0) == "unquote" then return word(obj_val(ast), 2)
ast00 = word(obj_val(ast0), 1)
if pair?(ast0) & symbol?(ast00) & obj_val(ast00) == "splice-unquote" then
return new_list(new_symbol("concat") || " " || word(obj_val(ast0), 2) || " " || quasiquote(mal_rest(ast)))
else
return new_list(new_symbol("cons") || " " || quasiquote(ast0) || " " || quasiquote(mal_rest(ast)))
macro?: procedure expose values. env. /* macro?(ast, env_idx) */
ast = arg(1)
env_idx = arg(2)
if \list?(ast) then return 0
ast0 = mal_first(ast)
if \symbol?(ast0) then return 0
if env_find(env_idx, obj_val(ast0)) == 0 then return 0
return func_macro?(env_get(env_idx, obj_val(ast0)))
macroexpand: procedure expose values. env. err /* macroexpand(ast, env_idx) */
ast = arg(1)
env_idx = arg(2)
do while macro?(ast, env_idx)
mac = env_get(env_idx, obj_val(mal_first(ast)))
call_args = mal_rest(ast)
mac_env_idx = new_env(func_env_idx(mac), func_binds(mac), call_args)
ast = eval(func_body_ast(mac), mac_env_idx)
end
return ast
eval_ast: procedure expose values. env. err /* eval_ast(ast, env_idx) */
ast = arg(1)
env_idx = arg(2)
type = obj_type(ast)
val = obj_val(ast)
select
when type == "symb" then return env_get(env_idx, val)
when type == "list" then do
res = ""
do i=1 to words(val)
element = eval(word(val, i), env_idx)
if element == "ERR" then return "ERR"
if i > 1 then
res = res || " " || element
else
res = element
end
return new_list(res)
end
when type == "vect" then do
res = ""
do i=1 to words(val)
element = eval(word(val, i), env_idx)
if element == "ERR" then return "ERR"
if i > 1 then
res = res || " " || element
else
res = element
end
return new_vector(res)
end
when type == "hash" then do
res = ""
do i=1 to words(val)
element = eval(word(val, i), env_idx)
if element == "ERR" then return "ERR"
if i > 1 then
res = res || " " || element
else
res = element
end
return new_hashmap(res)
end
otherwise
return ast
end
eval: procedure expose values. env. err /* eval(ast) */
ast = arg(1)
env_idx = arg(2)
do forever
if \list?(ast) then return eval_ast(ast, env_idx)
ast = macroexpand(ast, env_idx)
if \list?(ast) then return eval_ast(ast, env_idx)
astval = obj_val(ast)
if words(astval) == 0 then return ast
a0sym = obj_val(word(astval, 1))
select
when a0sym == "def!" then do
a1sym = obj_val(word(astval, 2))
a2 = eval(word(astval, 3), env_idx)
if a2 == "ERR" then return "ERR"
return env_set(env_idx, a1sym, a2)
end
when a0sym == "let*" then do
a1lst = obj_val(word(astval, 2))
letenv_idx = new_env(env_idx)
do i=1 to words(a1lst) by 2
k = obj_val(word(a1lst, i))
v = eval(word(a1lst, i + 1), letenv_idx)
if v == "ERR" then return "ERR"
unused = env_set(letenv_idx, k, v)
end
env_idx = letenv_idx
ast = word(astval, 3)
/* TCO */
end
when a0sym == "quote" then return word(astval, 2)
when a0sym == "quasiquote" then do
ast = quasiquote(word(astval, 2))
/* TCO */
end
when a0sym == "defmacro!" then do
a1sym = obj_val(word(astval, 2))
a2 = eval(word(astval, 3), env_idx)
if a2 == "ERR" then return "ERR"
return env_set(env_idx, a1sym, func_mark_as_macro(a2))
end
when a0sym == "macroexpand" then return macroexpand(word(astval, 2), env_idx)
when a0sym == "try*" then do
res = eval(word(astval, 2), env_idx)
if words(astval) < 3 then return res
if res == "ERR" then do
if word(err, 1) == "__MAL_EXCEPTION__" then
errobj = word(err, 2)
else
errobj = new_string(err)
catchlst = obj_val(word(astval, 3))
catch_env_idx = new_env(env_idx, new_list(word(catchlst, 2)), new_list(errobj))
err = ""
return eval(word(catchlst, 3), catch_env_idx)
end
else
return res
end
when a0sym == "do" then do
do i=2 to (words(astval) - 1)
res = eval(word(astval, i), env_idx)
if res == "ERR" then return "ERR"
end
ast = word(astval, words(astval))
/* TCO */
end
when a0sym == "if" then do
condval = eval(word(astval, 2), env_idx)
if false?(condval) | nil?(condval) then
if words(astval) >= 4 then
ast = word(astval, 4)
else
return new_nil()
else
ast = word(astval, 3)
/* TCO */
end
when a0sym == "fn*" then return new_func(word(astval, 3), env_idx, word(astval, 2))
otherwise
lst_obj = eval_ast(ast, env_idx)
if lst_obj == "ERR" then return "ERR"
lst = obj_val(lst_obj)
f = word(lst, 1)
select
when nativefn?(f) then do
call_args = subword(lst, 2)
call_list = ""
do i=1 to words(call_args)
element = '"' || word(call_args, i) || '"'
if i > 1 then
call_list = call_list || ', ' || element
else
call_list = element
end
res = ""
interpret "res = " || obj_val(f) || "(" || call_list || ")"
return res
end
when func?(f) then do
call_args = new_list(subword(lst, 2))
env_idx = new_env(func_env_idx(f), func_binds(f), call_args)
ast = func_body_ast(f)
/* TCO */
end
otherwise
err = "Unsupported function object type: " || obj_type(f)
return "ERR"
end
end
end
print: procedure expose values. /* print(ast) */
return pr_str(arg(1), 1)
re: procedure expose values. env. err repl_env_idx /* re(str) */
str = arg(1)
ast = read(str)
if ast == "ERR" then return "ERR"
return eval(ast, repl_env_idx)
rep: procedure expose values. env. err repl_env_idx /* rep(str) */
str = arg(1)
exp = re(str)
if exp == "ERR" then return "ERR"
return print(exp)
mal_eval: procedure expose values. env. err /* mal_eval(ast) */
ast = arg(1)
if ast == "ERR" then return "ERR"
return eval(arg(1), 1) /* repl_env_idx is always 1 because it's the first env */
build_args_list: procedure expose values. command_line_args. /* build_args_list() */
seq = ""
do i=2 to command_line_args.0
s = new_string(command_line_args.i)
if i == 1 then
seq = s
else
seq = seq || " " || s
end
return new_list(seq)
main:
values. = ""
values.0 = 0
env. = ""
env.0 = 0
repl_env_idx = new_env(0)
/* core.rexx: defined using Rexx */
core_ns = get_core_ns()
do i=1 to words(core_ns) by 2
x = env_set(repl_env_idx, word(core_ns, i), new_nativefn(word(core_ns, i + 1)))
end
x = env_set(repl_env_idx, "eval", new_nativefn("mal_eval"))
x = env_set(repl_env_idx, "*ARGV*", build_args_list())
/* core.mal: defined using the language itself */
x = re("(def! not (fn* (a) (if a false true)))")
x = re('(def! load-file (fn* (f) (eval (read-string (str "(do " (slurp f) ")")))))')
x = re("(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)))))))");
x = re("(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))))))))");
err = ""
if command_line_args.0 > 0 then do
x = re('(load-file "' || command_line_args.1 || '")')
return
end
do while lines() > 0 /* 1 == 1 */
input_line = readline('user> ')
if length(input_line) > 0 then do
res = rep(input_line)
if res == "ERR" then do
if word(err, 1) == "__MAL_EXCEPTION__" then
errstr = pr_str(word(err, 2), 0)
else
errstr = err
call lineout , "Error: " || errstr
err = ""
end
else
call lineout , res
end
end