Commit | Line | Data |
---|---|---|
23c5aa44 JM |
1 | function step5_tco(varargin), main(varargin), end |
2 | ||
3 | % read | |
4 | function ret = READ(str) | |
5 | ret = reader.read_str(str); | |
6 | end | |
7 | ||
8 | % eval | |
9 | function ret = eval_ast(ast, env) | |
10 | switch class(ast) | |
11 | case 'types.Symbol' | |
12 | ret = env.get(ast); | |
13 | case 'cell' | |
14 | ret = {}; | |
15 | for i=1:length(ast) | |
16 | ret{end+1} = EVAL(ast{i}, env); | |
17 | end | |
18 | otherwise | |
19 | ret = ast; | |
20 | end | |
21 | end | |
22 | ||
23 | function ret = EVAL(ast, env) | |
24 | while true | |
25 | if ~iscell(ast), | |
26 | ret = eval_ast(ast, env); | |
27 | return; | |
28 | end | |
29 | ||
30 | % apply | |
31 | if isa(ast{1},'types.Symbol') | |
32 | a1sym = ast{1}.name; | |
33 | else | |
34 | a1sym = '_@$fn$@_'; | |
35 | end | |
36 | switch (a1sym) | |
37 | case 'def!' | |
38 | ret = env.set(ast{2}, EVAL(ast{3}, env)); | |
39 | return; | |
40 | case 'let*' | |
41 | let_env = Env(env); | |
42 | for i=1:2:length(ast{2}) | |
43 | let_env.set(ast{2}{i}, EVAL(ast{2}{i+1}, let_env)); | |
44 | end | |
45 | env = let_env; | |
46 | ast = ast{3}; % TCO | |
47 | case 'do' | |
48 | el = eval_ast(ast(2:end-1), env); | |
49 | ast = ast{end}; % TCO | |
50 | case 'if' | |
51 | cond = EVAL(ast{2}, env); | |
52 | if strcmp(class(cond), 'types.Nil') || ... | |
53 | (islogical(cond) && cond == false) | |
54 | if length(ast) > 3 | |
55 | ast = ast{4}; % TCO | |
56 | else | |
57 | ret = types.nil; | |
58 | return; | |
59 | end | |
60 | else | |
61 | ast = ast{3}; % TCO | |
62 | end | |
63 | case 'fn*' | |
64 | fn = @(varargin) EVAL(ast{3}, Env(env, ast{2}, varargin)); | |
65 | ret = Function(fn, ast{3}, env, ast{2}); | |
66 | return; | |
67 | otherwise | |
68 | el = eval_ast(ast, env); | |
69 | f = el{1}; | |
70 | args = el(2:end); | |
71 | if isa(f, 'Function') | |
72 | env = Env(f.env, f.params, args); | |
73 | ast = f.ast; % TCO | |
74 | else | |
75 | ret = f(args{:}); | |
76 | return | |
77 | end | |
78 | end | |
79 | end | |
80 | end | |
81 | ||
82 | ||
83 | function ret = PRINT(ast) | |
84 | ret = printer.pr_str(ast, true); | |
85 | end | |
86 | ||
87 | % REPL | |
88 | function ret = rep(str, env) | |
89 | ret = PRINT(EVAL(READ(str), env)); | |
90 | end | |
91 | ||
92 | function main(args) | |
93 | repl_env = Env(false); | |
94 | ||
95 | % core.m: defined using matlab | |
96 | ns = core.ns(); ks = ns.keys(); | |
97 | for i=1:length(ks) | |
98 | k = ks{i}; | |
99 | repl_env.set(types.Symbol(k), ns(k)); | |
100 | end | |
101 | ||
102 | % core.mal: defined using the langauge itself | |
103 | rep('(def! not (fn* (a) (if a false true)))', repl_env); | |
104 | ||
105 | %cleanObj = onCleanup(@() disp('*** here1 ***')); | |
106 | while (true) | |
107 | line = input('user> ', 's'); | |
108 | if strcmp(strtrim(line),''), continue, end | |
109 | try | |
110 | fprintf('%s\n', rep(line, repl_env)); | |
111 | catch err | |
112 | fprintf('Error: %s\n', err.message); | |
113 | fprintf('%s\n', getReport(err, 'extended')); | |
114 | end | |
115 | end | |
116 | end |