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be17d0a6 NG |
1 | ;; Copyright (C) 2015 |
2 | ;; "Mu Lei" known as "NalaGinrut" <NalaGinrut@gmail.com> | |
3 | ;; This file is free software: you can redistribute it and/or modify | |
4 | ;; it under the terms of the GNU General Public License as published by | |
5 | ;; the Free Software Foundation, either version 3 of the License, or | |
6 | ;; (at your option) any later version. | |
7 | ||
8 | ;; This file is distributed in the hope that it will be useful, | |
9 | ;; but WITHOUT ANY WARRANTY; without even the implied warranty of | |
10 | ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
11 | ;; GNU General Public License for more details. | |
12 | ||
13 | ;; You should have received a copy of the GNU General Public License | |
14 | ;; along with this program. If not, see <http://www.gnu.org/licenses/>. | |
15 | ||
16 | (import (readline) (reader) (printer) (ice-9 match) (srfi srfi-43) | |
17 | (srfi srfi-1) (ice-9 receive) (env) (core) (types)) | |
18 | ||
19 | (define *toplevel* | |
dd7a4f55 | 20 | (receive (b e) (unzip2 core.ns) |
be17d0a6 NG |
21 | (make-Env #:binds b #:exprs e))) |
22 | ||
dd7a4f55 JM |
23 | (define (READ str) |
24 | (read_str str)) | |
be17d0a6 NG |
25 | |
26 | (define (eval_ast ast env) | |
27 | (define (_eval x) (EVAL x env)) | |
28 | (match ast | |
29 | ((? _nil? obj) obj) | |
ecba6e97 | 30 | ((? symbol? sym) (env-has sym env)) |
be17d0a6 NG |
31 | ((? list? lst) (map _eval lst)) |
32 | ((? vector? vec) (vector-map (lambda (i x) (_eval x)) vec)) | |
33 | ((? hash-table? ht) | |
dd7a4f55 JM |
34 | ;; NOTE: we must allocate a new hashmap here to avoid any side-effects, or |
35 | ;; there'll be strange bugs!!! | |
36 | (list->hash-map (hash-fold (lambda (k v p) (cons k (cons (_eval v) p))) '() ht))) | |
be17d0a6 NG |
37 | (else ast))) |
38 | ||
be17d0a6 NG |
39 | (define (eval_seq ast env) |
40 | (cond | |
41 | ((null? ast) nil) | |
42 | ((null? (cdr ast)) (EVAL (car ast) env)) | |
43 | (else | |
44 | (EVAL (car ast) env) | |
45 | (eval_seq (cdr ast) env)))) | |
46 | ||
47 | (define (EVAL ast env) | |
be17d0a6 NG |
48 | (define (%unzip2 kvs) |
49 | (let lp((next kvs) (k '()) (v '())) | |
50 | (cond | |
51 | ;; NOTE: reverse is very important here! | |
52 | ((null? next) (values (reverse k) (reverse v))) | |
dd7a4f55 JM |
53 | ((null? (cdr next)) |
54 | (throw 'mal-error (format #f "let*: Invalid binding form '~a'" kvs))) | |
be17d0a6 NG |
55 | (else (lp (cddr next) (cons (car next) k) (cons (cadr next) v)))))) |
56 | (match ast | |
dd7a4f55 | 57 | ((? non-list?) (eval_ast ast env)) |
81eabb99 | 58 | (() ast) |
be17d0a6 NG |
59 | (('def! k v) ((env 'set) k (EVAL v env))) |
60 | (('let* kvs body) | |
61 | (let* ((new-env (make-Env #:outer env)) | |
62 | (setter (lambda (k v) ((new-env 'set) k (EVAL v new-env))))) | |
63 | (receive (keys vals) (%unzip2 (->list kvs)) | |
64 | (for-each setter keys vals)) | |
65 | (EVAL body new-env))) | |
dd7a4f55 JM |
66 | (('do rest ...) |
67 | (eval_seq rest env)) | |
be17d0a6 NG |
68 | (('if cnd thn els ...) |
69 | (cond | |
70 | ((and (not (null? els)) (not (null? (cdr els)))) | |
71 | ;; Invalid `if' form | |
dd7a4f55 JM |
72 | (throw 'mal-error |
73 | (format #f "if: failed to match any pattern in form '~a'" ast))) | |
be17d0a6 NG |
74 | ((cond-true? (EVAL cnd env)) (EVAL thn env)) |
75 | (else (if (null? els) nil (EVAL (car els) env))))) | |
76 | (('fn* params body ...) ; function definition | |
77 | (lambda args | |
dc656104 | 78 | (eval_seq body (make-Env #:outer env #:binds (->list params) #:exprs args)))) |
dd7a4f55 JM |
79 | (else |
80 | (let ((el (map (lambda (x) (EVAL x env)) ast))) | |
81 | (apply (car el) (cdr el)))))) | |
be17d0a6 | 82 | |
17fc310d NB |
83 | (define (EVAL-string str) |
84 | (EVAL (read_str str) *toplevel*)) | |
85 | ||
be17d0a6 NG |
86 | (define (PRINT exp) |
87 | (and (not (eof-object? exp)) | |
be17d0a6 NG |
88 | (format #t "~a~%" (pr_str exp #t)))) |
89 | ||
90 | (define (LOOP continue?) | |
91 | (and continue? (REPL))) | |
92 | ||
93 | (define (REPL) | |
94 | (LOOP | |
dd7a4f55 JM |
95 | (let ((line (_readline "user> "))) |
96 | (cond | |
97 | ((eof-object? line) #f) | |
98 | ((string=? line "") #t) | |
99 | (else | |
100 | (catch 'mal-error | |
101 | (lambda () (PRINT (EVAL (READ line) *toplevel*))) | |
102 | (lambda (k . e) | |
103 | (format #t "Error: ~a~%" (pr_str (car e) #t))))))))) | |
be17d0a6 | 104 | |
17fc310d NB |
105 | (EVAL-string "(def! not (fn* (x) (if x false true)))") |
106 | ||
be17d0a6 | 107 | (REPL) |