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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* | |
20 | (receive (b e) (unzip2 core.ns) | |
21 | (make-Env #:binds b #:exprs e))) | |
22 | ||
23 | (define (READ) | |
94a0943a | 24 | (read_str (_readline "user> "))) |
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) | |
34 | (hash-for-each (lambda (k v) (hash-set! ht k (_eval v))) ht) | |
35 | ht) | |
36 | (else ast))) | |
37 | ||
38 | (define (eval_func ast env) | |
39 | (define expr (eval_ast ast env)) | |
40 | (match expr | |
41 | (((? procedure? proc) args ...) | |
42 | (apply proc args)) | |
98cd78e4 | 43 | (else (throw 'mal-error (format #f "'~a' not found" (car expr)))))) |
be17d0a6 NG |
44 | |
45 | (define (eval_seq ast env) | |
46 | (cond | |
47 | ((null? ast) nil) | |
48 | ((null? (cdr ast)) (EVAL (car ast) env)) | |
49 | (else | |
50 | (EVAL (car ast) env) | |
51 | (eval_seq (cdr ast) env)))) | |
52 | ||
53 | (define (EVAL ast env) | |
54 | (define (->list kvs) ((if (vector? kvs) vector->list identity) kvs)) | |
55 | (define (%unzip2 kvs) | |
56 | (let lp((next kvs) (k '()) (v '())) | |
57 | (cond | |
58 | ;; NOTE: reverse is very important here! | |
59 | ((null? next) (values (reverse k) (reverse v))) | |
60 | ((null? (cdr next)) (throw 'mal-error "let*: Invalid binding form" kvs)) | |
61 | (else (lp (cddr next) (cons (car next) k) (cons (cadr next) v)))))) | |
62 | (match ast | |
81eabb99 | 63 | (() ast) |
be17d0a6 NG |
64 | (('def! k v) ((env 'set) k (EVAL v env))) |
65 | (('let* kvs body) | |
66 | (let* ((new-env (make-Env #:outer env)) | |
67 | (setter (lambda (k v) ((new-env 'set) k (EVAL v new-env))))) | |
68 | (receive (keys vals) (%unzip2 (->list kvs)) | |
69 | (for-each setter keys vals)) | |
70 | (EVAL body new-env))) | |
71 | (('do rest ...) (eval_seq rest env)) | |
72 | (('if cnd thn els ...) | |
73 | (cond | |
74 | ((and (not (null? els)) (not (null? (cdr els)))) | |
75 | ;; Invalid `if' form | |
76 | (throw 'mal-error "failed to match any pattern in form " ast)) | |
77 | ((cond-true? (EVAL cnd env)) (EVAL thn env)) | |
78 | (else (if (null? els) nil (EVAL (car els) env))))) | |
79 | (('fn* params body ...) ; function definition | |
80 | (lambda args | |
dc656104 | 81 | (eval_seq body (make-Env #:outer env #:binds (->list params) #:exprs args)))) |
be17d0a6 NG |
82 | ((? list?) (eval_func ast env)) ; function calling |
83 | (else (eval_ast ast env)))) | |
84 | ||
85 | (define (PRINT exp) | |
86 | (and (not (eof-object? exp)) | |
be17d0a6 NG |
87 | (format #t "~a~%" (pr_str exp #t)))) |
88 | ||
89 | (define (LOOP continue?) | |
90 | (and continue? (REPL))) | |
91 | ||
92 | (define (REPL) | |
93 | (LOOP | |
94 | (catch 'mal-error | |
95 | (lambda () (PRINT (EVAL (READ) *toplevel*))) | |
96 | (lambda (k . e) | |
f33a3d58 NG |
97 | (if (string=? (car e) "blank line") |
98 | (display "") | |
99 | (format #t "Error: ~a~%" (car e))))))) | |
be17d0a6 NG |
100 | |
101 | (REPL) |