blob: 191686cb8c56599a2fac9931e38f01e5a601594c (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
|
(ns lang.lexer
(:require [clojure.core.match :refer [match]]
[lang.util :as &util :refer [exec return* return fail fail*
repeat-m try-m try-all-m]]))
(declare lex-form)
;; [Utils]
(defn ^:private lex-regex [regex]
(fn [text]
(if-let [[match] (re-find regex text)]
(return* (.substring text (.length match)) match)
(fail* "Pattern failed."))))
(defn ^:private lex-str [str]
(fn [text]
(if (.startsWith text str)
(return* (.substring text (.length str)) str)
(fail* "String failed."))))
;; [Lexers]
(def ^:private lex-white-space (lex-regex #"^(\s+)"))
(def ^:private lex-list
(exec [_ (lex-str "(")
members (repeat-m lex-form)
_ (lex-str ")")]
(return [::list members])))
(def ^:private lex-ident
(exec [token (lex-regex #"^([a-zA-Z!@$%^&*<>\.,/\\\|][a-zA-Z0-9!@$%^&*<>\.,/\\\|]*)")]
(return [::ident token])))
(def ^:private lex-int
(exec [token (lex-regex #"^([1-9][0-9]*)")]
(return [::int token])))
(def ^:private lex-form
(exec [_ (try-m lex-white-space)
form (try-all-m [lex-list
lex-ident
lex-int
])
_ (try-m lex-white-space)]
(return form)))
;; [Interface]
(defn lex [text]
(match ((exec [_ (try-m lex-white-space)
form lex-list
_ (try-m lex-white-space)]
(return form))
text)
[::&util/ok [?state ?datum]]
(if (empty? ?state)
?datum
(assert false (str "Unconsumed input: " ?state)))
[::&util/failure ?message]
(assert false ?message)))
|
