mirror of
https://github.com/kanaka/mal.git
synced 2024-09-20 01:57:09 +03:00
e6d41de4d5
Let `load-file` append a new line in case last line contains a comment. Also append `nil` so that the return value is predictible. Remove the existing explicit `nil` from existing sources. Adapt documentation and tests.
235 lines
6.8 KiB
Rexx
235 lines
6.8 KiB
Rexx
/* Save command-line arguments from the top-level program before entering a procedure */
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command_line_args. = ""
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command_line_args.0 = arg()
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do i=1 to command_line_args.0
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command_line_args.i = arg(i)
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end
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call main
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exit
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#include "readline.rexx"
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#include "reader.rexx"
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#include "printer.rexx"
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#include "types.rexx"
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#include "env.rexx"
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#include "core.rexx"
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read: procedure expose values. err /* read(str) */
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return read_str(arg(1))
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pair?: procedure expose values. /* pair?(ast) */
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ast = arg(1)
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return sequential?(ast) & words(obj_val(ast)) > 0
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quasiquote: procedure expose values. env. err /* quasiquote(ast) */
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ast = arg(1)
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if \pair?(ast) then return new_list(new_symbol("quote") || " " || ast)
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ast0 = word(obj_val(ast), 1)
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if symbol?(ast0) & obj_val(ast0) == "unquote" then return word(obj_val(ast), 2)
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ast00 = word(obj_val(ast0), 1)
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if pair?(ast0) & symbol?(ast00) & obj_val(ast00) == "splice-unquote" then
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return new_list(new_symbol("concat") || " " || word(obj_val(ast0), 2) || " " || quasiquote(mal_rest(ast)))
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else
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return new_list(new_symbol("cons") || " " || quasiquote(ast0) || " " || quasiquote(mal_rest(ast)))
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eval_ast: procedure expose values. env. err /* eval_ast(ast, env_idx) */
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ast = arg(1)
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env_idx = arg(2)
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type = obj_type(ast)
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val = obj_val(ast)
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select
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when type == "symb" then return env_get(env_idx, val)
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when type == "list" then do
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res = ""
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do i=1 to words(val)
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element = eval(word(val, i), env_idx)
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if element == "ERR" then return "ERR"
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if i > 1 then
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res = res || " " || element
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else
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res = element
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end
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return new_list(res)
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end
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when type == "vect" then do
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res = ""
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do i=1 to words(val)
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element = eval(word(val, i), env_idx)
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if element == "ERR" then return "ERR"
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if i > 1 then
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res = res || " " || element
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else
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res = element
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end
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return new_vector(res)
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end
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when type == "hash" then do
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res = ""
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do i=1 to words(val)
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element = eval(word(val, i), env_idx)
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if element == "ERR" then return "ERR"
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if i > 1 then
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res = res || " " || element
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else
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res = element
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end
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return new_hashmap(res)
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end
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otherwise
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return ast
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end
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eval: procedure expose values. env. err /* eval(ast) */
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ast = arg(1)
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env_idx = arg(2)
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do forever
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if \list?(ast) then return eval_ast(ast, env_idx)
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astval = obj_val(ast)
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if words(astval) == 0 then return ast
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a0sym = obj_val(word(astval, 1))
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select
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when a0sym == "def!" then do
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a1sym = obj_val(word(astval, 2))
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a2 = eval(word(astval, 3), env_idx)
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if a2 == "ERR" then return "ERR"
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return env_set(env_idx, a1sym, a2)
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end
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when a0sym == "let*" then do
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a1lst = obj_val(word(astval, 2))
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letenv_idx = new_env(env_idx)
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do i=1 to words(a1lst) by 2
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k = obj_val(word(a1lst, i))
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v = eval(word(a1lst, i + 1), letenv_idx)
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if v == "ERR" then return "ERR"
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unused = env_set(letenv_idx, k, v)
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end
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env_idx = letenv_idx
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ast = word(astval, 3)
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/* TCO */
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end
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when a0sym == "quote" then return word(astval, 2)
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when a0sym == "quasiquote" then do
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ast = quasiquote(word(astval, 2))
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/* TCO */
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end
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when a0sym == "do" then do
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do i=2 to (words(astval) - 1)
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res = eval(word(astval, i), env_idx)
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if res == "ERR" then return "ERR"
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end
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ast = word(astval, words(astval))
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/* TCO */
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end
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when a0sym == "if" then do
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condval = eval(word(astval, 2), env_idx)
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if false?(condval) | nil?(condval) then
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if words(astval) >= 4 then
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ast = word(astval, 4)
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else
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return new_nil()
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else
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ast = word(astval, 3)
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/* TCO */
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end
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when a0sym == "fn*" then return new_func(word(astval, 3), env_idx, word(astval, 2))
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otherwise
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lst_obj = eval_ast(ast, env_idx)
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if lst_obj == "ERR" then return "ERR"
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lst = obj_val(lst_obj)
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f = word(lst, 1)
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select
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when nativefn?(f) then do
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call_args = subword(lst, 2)
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call_list = ""
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do i=1 to words(call_args)
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element = '"' || word(call_args, i) || '"'
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if i > 1 then
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call_list = call_list || ', ' || element
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else
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call_list = element
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end
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res = ""
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interpret "res = " || obj_val(f) || "(" || call_list || ")"
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return res
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end
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when func?(f) then do
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call_args = new_list(subword(lst, 2))
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env_idx = new_env(func_env_idx(f), func_binds(f), call_args)
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ast = func_body_ast(f)
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/* TCO */
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end
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otherwise
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err = "Unsupported function object type: " || obj_type(f)
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return "ERR"
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end
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end
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end
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print: procedure expose values. /* print(ast) */
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return pr_str(arg(1), 1)
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re: procedure expose values. env. err repl_env_idx /* re(str) */
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str = arg(1)
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ast = read(str)
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if ast == "ERR" then return "ERR"
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return eval(ast, repl_env_idx)
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rep: procedure expose values. env. err repl_env_idx /* rep(str) */
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str = arg(1)
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exp = re(str)
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if exp == "ERR" then return "ERR"
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return print(exp)
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mal_eval: procedure expose values. env. err /* mal_eval(ast) */
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ast = arg(1)
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if ast == "ERR" then return "ERR"
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return eval(arg(1), 1) /* repl_env_idx is always 1 because it's the first env */
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build_args_list: procedure expose values. command_line_args. /* build_args_list() */
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seq = ""
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do i=2 to command_line_args.0
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s = new_string(command_line_args.i)
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if i == 1 then
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seq = s
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else
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seq = seq || " " || s
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end
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return new_list(seq)
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main:
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values. = ""
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values.0 = 0
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env. = ""
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env.0 = 0
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repl_env_idx = new_env(0)
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/* core.rexx: defined using Rexx */
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core_ns = get_core_ns()
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do i=1 to words(core_ns) by 2
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x = env_set(repl_env_idx, word(core_ns, i), new_nativefn(word(core_ns, i + 1)))
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end
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x = env_set(repl_env_idx, "eval", new_nativefn("mal_eval"))
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x = env_set(repl_env_idx, "*ARGV*", build_args_list())
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/* core.mal: defined using the language itself */
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x = re("(def! not (fn* (a) (if a false true)))")
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x = re('(def! load-file (fn* (f) (eval (read-string (str "(do " (slurp f) "\nnil)")))))')
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err = ""
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if command_line_args.0 > 0 then do
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x = re('(load-file "' || command_line_args.1 || '")')
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return
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end
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do while lines() > 0 /* 1 == 1 */
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input_line = readline('user> ')
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if length(input_line) > 0 then do
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res = rep(input_line)
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if res == "ERR" then
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call lineout , "Error: " || err
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else
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call lineout , res
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end
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end
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