blob: 2acc811fb8726916aea885369d2ba87b8592cc53 (
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
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
|
;; -*- mode: lisp; coding: utf-8 -*-
;;
;; Copyright 2011, Matthias Andreas Benkard.
;;
;; Licensed under the Apache License, Version 2.0 (the "License");
;; you may not use this file except in compliance with the License.
;; You may obtain a copy of the License at
;;
;; http://www.apache.org/licenses/LICENSE-2.0
;;
;; Unless required by applicable law or agreed to in writing, software
;; distributed under the License is distributed on an "AS IS" BASIS,
;; WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
;; See the License for the specific language governing permissions and
;; limitations under the License.
(defpackage #:json-template
(:use #:common-lisp)
(:export #:parse-template-string
#:expand-template
#:*template-formatters*))
(in-package #:json-template)
(defvar *template-formatters*
`(;;("html" . format-html)
;;("html-attr-value" . format-html-attr-value)
("raw" . identity)))
(defun tokenize-template-string (string)
(loop with in-command-p = nil
with skip-newline-p = nil
with position = 0
for terminator = (position (if in-command-p #\} #\{) string
:start position)
collect (cons in-command-p
(subseq string
position
(or terminator (length string))))
do (setq position (and terminator (1+ terminator)))
when (and skip-newline-p
position
(< position (length string))
(char= (char string position) #\Newline))
do (incf position)
do (setq in-command-p (not in-command-p)
skip-newline-p (and in-command-p
position
(member (char string position)
(list #\. #\#))))
until (null terminator)))
(defun parse-template-string (stream)
(parse-raw-tokens (tokenize-template-string stream)))
(defun parse-directive (string)
(let* ((space1 (position #\Space string))
(space2 (and space1 (position #\Space string :start (1+ space1)))))
(list (intern (string-upcase (subseq string 1 (or space1 (length string))))
'#:keyword)
(if space1
(subseq string (1+ space1) (or space2 (length string)))
nil)
(if space2
(subseq string (1+ space2))
nil))))
(defun parse-variable (string)
(let ((pipe (position #\| string)))
(if pipe
(list (subseq string 0 pipe)
(subseq string (1+ pipe)))
(list string nil))))
(defun parse-token (token)
(destructuring-bind (command-p . data)
token
(if command-p
(case (char data 0)
((#\.)
(list* :directive (parse-directive data)))
((#\#)
(list* :comment data))
(otherwise
(list* :variable (parse-variable data))))
(list :text data))))
(defun parse-raw-tokens (tokens)
(parse-tokens (mapcar #'parse-token tokens)))
(defun parse-tokens (tokens)
(let ((result (loop for token = (and tokens (car tokens))
for token-kind = (first token)
for token-data = (rest token)
until (or (null tokens)
(and (eq token-kind :directive)
(member (second token) '(:or :end))))
do (setq tokens (cdr tokens))
if (eq token-kind :directive)
collect (multiple-value-bind (subresult rest-tokens)
(parse-tokens tokens)
(let ((sub-end-tag (first rest-tokens)))
(setq tokens (rest rest-tokens))
(let ((alternative
(and (equal sub-end-tag '(:directive :or nil nil))
(multiple-value-bind (altresult rest-tokens2)
(parse-tokens tokens)
(setq tokens (rest rest-tokens2))
altresult))))
(ecase (first token-data)
(:section
(list :section
(second token-data)
subresult
alternative))
(:repeated
(list :repeated-section
(third token-data)
subresult
alternative))))))
else if (member token-kind '(:variable :text))
collect token
else if (eq token-kind :comment)
do (progn)
else do (error "Encountered invalid token: ~S" token))))
(values result tokens)))
(defun expand-template (template context)
(with-output-to-string (out)
(expand-template-to-stream template (list context) out)))
(defun getcontext (context key &aux (result context))
(dolist (key-component key result)
(setq result
(getf result
key-component
nil))))
(defun listify-key (key &optional (start 0))
(let ((dot (position #\. key :start start)))
(if dot
(cons (intern (string-upcase (subseq key start dot))
'#:keyword)
(listify-key key (1+ dot)))
(list (intern (string-upcase (subseq key start))
'#:keyword)))))
(defun lookup-context (contexts key)
(when (string= key "@")
(return-from lookup-context (first contexts)))
(unless (listp key)
(setq key (listify-key key)))
(labels ((lookup-in-stack (context-stack)
(if (endp context-stack)
nil
(or (getcontext (first context-stack) key)
(lookup-in-stack (rest context-stack))))))
(lookup-in-stack contexts)))
(defun expand-template-to-stream (template contexts stream)
(dolist (thing template)
(ecase (first thing)
(:text
(write-string (second thing) stream))
(:variable
(destructuring-bind (variable formatter) (cdr thing)
(let ((value (lookup-context contexts variable)))
(format stream "~A"
(if formatter
(funcall (cdr (assoc formatter *template-formatters*
:test #'equal))
value)
value)))))
(:section
(destructuring-bind (section branch alternative) (cdr thing)
(let ((value (lookup-context contexts section)))
(expand-template-to-stream (if value branch alternative)
(cons value contexts)
stream))))
(:repeated-section
(destructuring-bind (section branch alternative) (cdr thing)
(let ((value (lookup-context contexts section)))
(if value
(mapc (lambda (ctx)
(expand-template-to-stream branch (cons ctx contexts) stream))
value)
(expand-template-to-stream alternative contexts stream))))))))
|
