html/014literal_string.cc.html


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
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<html>
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<title>Mu - 014literal_string.cc</title>
<meta name="Generator" content="Vim/7.4">
<meta name="plugin-version" content="vim7.4_v2">
<meta name="syntax" content="cpp">
<meta name="settings" content="use_css,pre_wrap,no_foldcolumn,expand_tabs,prevent_copy=">
<meta name="colorscheme" content="minimal">
<style type="text/css">
<!--
pre { white-space: pre-wrap; font-family: monospace; color: #eeeeee; background-color: #080808; }
body { font-size: 12pt; font-family: monospace; color: #eeeeee; background-color: #080808; }
* { font-size: 12pt; font-size: 1em; }
.Constant { color: #00a0a0; }
.cSpecial { color: #008000; }
.muRecipe { color: #ff8700; }
.Comment { color: #9090ff; }
.Delimiter { color: #800080; }
.Special { color: #c00000; }
.traceContains { color: #008000; }
.Normal { color: #eeeeee; background-color: #080808; padding-bottom: 1px; }
.Identifier { color: #c0a020; }
-->
</style>

<script type='text/javascript'>
<!--

-->
</script>
</head>
<body>
<pre id='vimCodeElement'>
<span class="Comment">//: For convenience, some instructions will take literal arrays of characters</span>
<span class="Comment">//: (text or strings).</span>
<span class="Comment">//:</span>
<span class="Comment">//: Instead of quotes, we'll use [] to delimit strings. That'll reduce the</span>
<span class="Comment">//: need for escaping since we can support nested brackets. And we can also</span>
<span class="Comment">//: imagine that 'recipe' might one day itself be defined in mu, doing its own</span>
<span class="Comment">//: parsing.</span>

<span class="Delimiter">:(scenarios load)</span>
<span class="Delimiter">:(scenario string_literal)</span>
<span class="muRecipe">def</span> main [
  <span class="Constant">1</span>:address:array:character<span class="Special"> &lt;- </span>copy [abc def]
]
<span class="traceContains">+parse:   ingredient: {&quot;abc def&quot;: &quot;literal-string&quot;}</span>

<span class="Delimiter">:(scenario string_literal_with_colons)</span>
<span class="muRecipe">def</span> main [
  <span class="Constant">1</span>:address:array:character<span class="Special"> &lt;- </span>copy [abc:def/ghi]
]
<span class="traceContains">+parse:   ingredient: {&quot;abc:def/ghi&quot;: &quot;literal-string&quot;}</span>

<span class="Delimiter">:(before &quot;End Mu Types Initialization&quot;)</span>
put<span class="Delimiter">(</span>Type_ordinal<span class="Delimiter">,</span> <span class="Constant">&quot;literal-string&quot;</span><span class="Delimiter">,</span> <span class="Constant">0</span><span class="Delimiter">);</span>

<span class="Delimiter">:(before &quot;End next_word Special-cases&quot;)</span>
<span class="Normal">if</span> <span class="Delimiter">(</span>in<span class="Delimiter">.</span>peek<span class="Delimiter">()</span> == <span class="Constant">'['</span><span class="Delimiter">)</span> <span class="Delimiter">{</span>
  string result = slurp_quoted<span class="Delimiter">(</span>in<span class="Delimiter">);</span>
  skip_whitespace_and_comments_but_not_newline<span class="Delimiter">(</span>in<span class="Delimiter">);</span>
  <span class="Identifier">return</span> result<span class="Delimiter">;</span>
<span class="Delimiter">}</span>

<span class="Delimiter">:(code)</span>
string slurp_quoted<span class="Delimiter">(</span>istream&amp; in<span class="Delimiter">)</span> <span class="Delimiter">{</span>
  ostringstream out<span class="Delimiter">;</span>
  assert<span class="Delimiter">(</span>has_data<span class="Delimiter">(</span>in<span class="Delimiter">));</span>  assert<span class="Delimiter">(</span>in<span class="Delimiter">.</span>peek<span class="Delimiter">()</span> == <span class="Constant">'['</span><span class="Delimiter">);</span>  out &lt;&lt; <span class="Normal">static_cast</span>&lt;<span class="Normal">char</span>&gt;<span class="Delimiter">(</span>in<span class="Delimiter">.</span>get<span class="Delimiter">());</span>  <span class="Comment">// slurp the '['</span>
  <span class="Normal">if</span> <span class="Delimiter">(</span>is_code_string<span class="Delimiter">(</span>in<span class="Delimiter">,</span> out<span class="Delimiter">))</span>
    slurp_quoted_comment_aware<span class="Delimiter">(</span>in<span class="Delimiter">,</span> out<span class="Delimiter">);</span>
  <span class="Normal">else</span>
    slurp_quoted_comment_oblivious<span class="Delimiter">(</span>in<span class="Delimiter">,</span> out<span class="Delimiter">);</span>
  <span class="Identifier">return</span> out<span class="Delimiter">.</span>str<span class="Delimiter">();</span>
<span class="Delimiter">}</span>

<span class="Comment">// A string is a code string (ignores comments when scanning for matching</span>
<span class="Comment">// brackets) if it contains a newline at the start before any non-whitespace.</span>
<span class="Normal">bool</span> is_code_string<span class="Delimiter">(</span>istream&amp; in<span class="Delimiter">,</span> ostream&amp; out<span class="Delimiter">)</span> <span class="Delimiter">{</span>
  <span class="Normal">while</span> <span class="Delimiter">(</span>has_data<span class="Delimiter">(</span>in<span class="Delimiter">))</span> <span class="Delimiter">{</span>
    <span class="Normal">char</span> c = in<span class="Delimiter">.</span>get<span class="Delimiter">();</span>
    <span class="Normal">if</span> <span class="Delimiter">(</span>!isspace<span class="Delimiter">(</span>c<span class="Delimiter">))</span> <span class="Delimiter">{</span>
      in<span class="Delimiter">.</span>putback<span class="Delimiter">(</span>c<span class="Delimiter">);</span>
      <span class="Identifier">return</span> <span class="Constant">false</span><span class="Delimiter">;</span>
    <span class="Delimiter">}</span>
    out &lt;&lt; c<span class="Delimiter">;</span>
    <span class="Normal">if</span> <span class="Delimiter">(</span>c == <span class="cSpecial">'\n'</span><span class="Delimiter">)</span> <span class="Delimiter">{</span>
      <span class="Identifier">return</span> <span class="Constant">true</span><span class="Delimiter">;</span>
    <span class="Delimiter">}</span>
  <span class="Delimiter">}</span>
  <span class="Identifier">return</span> <span class="Constant">false</span><span class="Delimiter">;</span>
<span class="Delimiter">}</span>

<span class="Comment">// Read a regular string. Regular strings can only contain other regular</span>
<span class="Comment">// strings.</span>
<span class="Normal">void</span> slurp_quoted_comment_oblivious<span class="Delimiter">(</span>istream&amp; in<span class="Delimiter">,</span> ostream&amp; out<span class="Delimiter">)</span> <span class="Delimiter">{</span>
  <span class="Normal">int</span> brace_depth = <span class="Constant">1</span><span class="Delimiter">;</span>
  <span class="Normal">while</span> <span class="Delimiter">(</span>has_data<span class="Delimiter">(</span>in<span class="Delimiter">))</span> <span class="Delimiter">{</span>
    <span class="Normal">char</span> c = in<span class="Delimiter">.</span>get<span class="Delimiter">();</span>
    <span class="Normal">if</span> <span class="Delimiter">(</span>c == <span class="cSpecial">'\\'</span><span class="Delimiter">)</span> <span class="Delimiter">{</span>
      slurp_one_past_backslashes<span class="Delimiter">(</span>in<span class="Delimiter">,</span> out<span class="Delimiter">);</span>
      <span class="Identifier">continue</span><span class="Delimiter">;</span>
    <span class="Delimiter">}</span>
    out &lt;&lt; c<span class="Delimiter">;</span>
    <span class="Normal">if</span> <span class="Delimiter">(</span>c == <span class="Constant">'['</span><span class="Delimiter">)</span> ++brace_depth<span class="Delimiter">;</span>
    <span class="Normal">if</span> <span class="Delimiter">(</span>c == <span class="Constant">']'</span><span class="Delimiter">)</span> --brace_depth<span class="Delimiter">;</span>
    <span class="Normal">if</span> <span class="Delimiter">(</span>brace_depth == <span class="Constant">0</span><span class="Delimiter">)</span> <span class="Identifier">break</span><span class="Delimiter">;</span>
  <span class="Delimiter">}</span>
  <span class="Normal">if</span> <span class="Delimiter">(</span>!has_data<span class="Delimiter">(</span>in<span class="Delimiter">)</span> &amp;&amp; brace_depth &gt; <span class="Constant">0</span><span class="Delimiter">)</span> <span class="Delimiter">{</span>
    raise &lt;&lt; <span class="Constant">&quot;unbalanced '['</span><span class="cSpecial">\n</span><span class="Constant">&quot;</span> &lt;&lt; end<span class="Delimiter">();</span>
    out<span class="Delimiter">.</span>clear<span class="Delimiter">();</span>
  <span class="Delimiter">}</span>
<span class="Delimiter">}</span>

<span class="Comment">// Read a code string. Code strings can contain either code or regular strings.</span>
<span class="Normal">void</span> slurp_quoted_comment_aware<span class="Delimiter">(</span>istream&amp; in<span class="Delimiter">,</span> ostream&amp; out<span class="Delimiter">)</span> <span class="Delimiter">{</span>
  <span class="Normal">char</span> c<span class="Delimiter">;</span>
  <span class="Normal">while</span> <span class="Delimiter">(</span>in &gt;&gt; c<span class="Delimiter">)</span> <span class="Delimiter">{</span>
    <span class="Normal">if</span> <span class="Delimiter">(</span>c == <span class="cSpecial">'\\'</span><span class="Delimiter">)</span> <span class="Delimiter">{</span>
      slurp_one_past_backslashes<span class="Delimiter">(</span>in<span class="Delimiter">,</span> out<span class="Delimiter">);</span>
      <span class="Identifier">continue</span><span class="Delimiter">;</span>
    <span class="Delimiter">}</span>
    <span class="Normal">if</span> <span class="Delimiter">(</span>c == <span class="Constant">'#'</span><span class="Delimiter">)</span> <span class="Delimiter">{</span>
      out &lt;&lt; c<span class="Delimiter">;</span>
      <span class="Normal">while</span> <span class="Delimiter">(</span>has_data<span class="Delimiter">(</span>in<span class="Delimiter">)</span> &amp;&amp; in<span class="Delimiter">.</span>peek<span class="Delimiter">()</span> != <span class="cSpecial">'\n'</span><span class="Delimiter">)</span> out &lt;&lt; <span class="Normal">static_cast</span>&lt;<span class="Normal">char</span>&gt;<span class="Delimiter">(</span>in<span class="Delimiter">.</span>get<span class="Delimiter">());</span>
      <span class="Identifier">continue</span><span class="Delimiter">;</span>
    <span class="Delimiter">}</span>
    <span class="Normal">if</span> <span class="Delimiter">(</span>c == <span class="Constant">'['</span><span class="Delimiter">)</span> <span class="Delimiter">{</span>
      in<span class="Delimiter">.</span>putback<span class="Delimiter">(</span>c<span class="Delimiter">);</span>
      <span class="Comment">// recurse</span>
      out &lt;&lt; slurp_quoted<span class="Delimiter">(</span>in<span class="Delimiter">);</span>
      <span class="Identifier">continue</span><span class="Delimiter">;</span>
    <span class="Delimiter">}</span>
    out &lt;&lt; c<span class="Delimiter">;</span>
    <span class="Normal">if</span> <span class="Delimiter">(</span>c == <span class="Constant">']'</span><span class="Delimiter">)</span> <span class="Identifier">return</span><span class="Delimiter">;</span>
  <span class="Delimiter">}</span>
  raise &lt;&lt; <span class="Constant">&quot;unbalanced '['</span><span class="cSpecial">\n</span><span class="Constant">&quot;</span> &lt;&lt; end<span class="Delimiter">();</span>
  out<span class="Delimiter">.</span>clear<span class="Delimiter">();</span>
<span class="Delimiter">}</span>

<span class="Delimiter">:(after &quot;Parsing reagent(string s)&quot;)</span>
<span class="Normal">if</span> <span class="Delimiter">(</span>starts_with<span class="Delimiter">(</span>s<span class="Delimiter">,</span> <span class="Constant">&quot;[&quot;</span><span class="Delimiter">))</span> <span class="Delimiter">{</span>
  <span class="Normal">if</span> <span class="Delimiter">(</span>*s<span class="Delimiter">.</span>rbegin<span class="Delimiter">()</span> != <span class="Constant">']'</span><span class="Delimiter">)</span> <span class="Identifier">return</span><span class="Delimiter">;</span>  <span class="Comment">// unbalanced bracket; handled elsewhere</span>
  name = s<span class="Delimiter">;</span>
  <span class="Comment">// delete [] delimiters</span>
  name<span class="Delimiter">.</span>erase<span class="Delimiter">(</span><span class="Constant">0</span><span class="Delimiter">,</span> <span class="Constant">1</span><span class="Delimiter">);</span>
  strip_last<span class="Delimiter">(</span>name<span class="Delimiter">);</span>
  type = <span class="Normal">new</span> type_tree<span class="Delimiter">(</span><span class="Constant">&quot;literal-string&quot;</span><span class="Delimiter">,</span> <span class="Constant">0</span><span class="Delimiter">);</span>
  <span class="Identifier">return</span><span class="Delimiter">;</span>
<span class="Delimiter">}</span>

<span class="Comment">//: Unlike other reagents, escape newlines in literal strings to make them</span>
<span class="Comment">//: more friendly to trace().</span>

<span class="Delimiter">:(after &quot;string to_string(const reagent&amp; r)&quot;)</span>
  <span class="Normal">if</span> <span class="Delimiter">(</span>is_literal_text<span class="Delimiter">(</span>r<span class="Delimiter">))</span>
    <span class="Identifier">return</span> emit_literal_string<span class="Delimiter">(</span>r<span class="Delimiter">.</span>name<span class="Delimiter">);</span>

<span class="Delimiter">:(code)</span>
<span class="Normal">bool</span> is_literal_text<span class="Delimiter">(</span><span class="Normal">const</span> reagent&amp; x<span class="Delimiter">)</span> <span class="Delimiter">{</span>
  <span class="Identifier">return</span> x<span class="Delimiter">.</span>type &amp;&amp; x<span class="Delimiter">.</span>type<span class="Delimiter">-&gt;</span>name == <span class="Constant">&quot;literal-string&quot;</span><span class="Delimiter">;</span>
<span class="Delimiter">}</span>

string emit_literal_string<span class="Delimiter">(</span>string name<span class="Delimiter">)</span> <span class="Delimiter">{</span>
  <span class="Normal">size_t</span> pos = <span class="Constant">0</span><span class="Delimiter">;</span>
  <span class="Normal">while</span> <span class="Delimiter">(</span>pos != string::npos<span class="Delimiter">)</span>
    pos = replace<span class="Delimiter">(</span>name<span class="Delimiter">,</span> <span class="Constant">&quot;</span><span class="cSpecial">\n</span><span class="Constant">&quot;</span><span class="Delimiter">,</span> <span class="Constant">&quot;</span><span class="cSpecial">\\</span><span class="Constant">n&quot;</span><span class="Delimiter">,</span> pos<span class="Delimiter">);</span>
  <span class="Identifier">return</span> <span class="Constant">&quot;{</span><span class="cSpecial">\&quot;</span><span class="Constant">&quot;</span>+name+<span class="Constant">&quot;</span><span class="cSpecial">\&quot;</span><span class="Constant">: </span><span class="cSpecial">\&quot;</span><span class="Constant">literal-string</span><span class="cSpecial">\&quot;</span><span class="Constant">}&quot;</span><span class="Delimiter">;</span>
<span class="Delimiter">}</span>

<span class="Normal">size_t</span> replace<span class="Delimiter">(</span>string&amp; str<span class="Delimiter">,</span> <span class="Normal">const</span> string&amp; from<span class="Delimiter">,</span> <span class="Normal">const</span> string&amp; to<span class="Delimiter">,</span> <span class="Normal">size_t</span> n<span class="Delimiter">)</span> <span class="Delimiter">{</span>
  <span class="Normal">size_t</span> result = str<span class="Delimiter">.</span>find<span class="Delimiter">(</span>from<span class="Delimiter">,</span> n<span class="Delimiter">);</span>
  <span class="Normal">if</span> <span class="Delimiter">(</span>result != string::npos<span class="Delimiter">)</span>
    str<span class="Delimiter">.</span>replace<span class="Delimiter">(</span>result<span class="Delimiter">,</span> from<span class="Delimiter">.</span>length<span class="Delimiter">(),</span> to<span class="Delimiter">);</span>
  <span class="Identifier">return</span> result<span class="Delimiter">;</span>
<span class="Delimiter">}</span>

<span class="Normal">void</span> strip_last<span class="Delimiter">(</span>string&amp; s<span class="Delimiter">)</span> <span class="Delimiter">{</span>
  <span class="Normal">if</span> <span class="Delimiter">(</span>!s<span class="Delimiter">.</span>empty<span class="Delimiter">())</span> s<span class="Delimiter">.</span>erase<span class="Delimiter">(</span>SIZE<span class="Delimiter">(</span>s<span class="Delimiter">)</span>-<span class="Constant">1</span><span class="Delimiter">);</span>
<span class="Delimiter">}</span>

<span class="Normal">void</span> slurp_one_past_backslashes<span class="Delimiter">(</span>istream&amp; in<span class="Delimiter">,</span> ostream&amp; out<span class="Delimiter">)</span> <span class="Delimiter">{</span>
  <span class="Comment">// When you encounter a backslash, strip it out and pass through any</span>
  <span class="Comment">// following run of backslashes. If we 'escaped' a single following</span>
  <span class="Comment">// character, then the character '\' would be:</span>
  <span class="Comment">//   '\\' escaped once</span>
  <span class="Comment">//   '\\\\' escaped twice</span>
  <span class="Comment">//   '\\\\\\\\' escaped thrice (8 backslashes)</span>
  <span class="Comment">// ..and so on. With our approach it'll be:</span>
  <span class="Comment">//   '\\' escaped once</span>
  <span class="Comment">//   '\\\' escaped twice</span>
  <span class="Comment">//   '\\\\' escaped thrice</span>
  <span class="Comment">// This only works as long as backslashes aren't also overloaded to create</span>
  <span class="Comment">// special characters. So Mu doesn't follow C's approach of overloading</span>
  <span class="Comment">// backslashes both to escape quote characters and also as a notation for</span>
  <span class="Comment">// unprintable characters like '\n'.</span>
  <span class="Normal">while</span> <span class="Delimiter">(</span>has_data<span class="Delimiter">(</span>in<span class="Delimiter">))</span> <span class="Delimiter">{</span>
    <span class="Normal">char</span> c = in<span class="Delimiter">.</span>get<span class="Delimiter">();</span>
    out &lt;&lt; c<span class="Delimiter">;</span>
    <span class="Normal">if</span> <span class="Delimiter">(</span>c != <span class="cSpecial">'\\'</span><span class="Delimiter">)</span> <span class="Identifier">break</span><span class="Delimiter">;</span>
  <span class="Delimiter">}</span>
<span class="Delimiter">}</span>

<span class="Delimiter">:(scenario string_literal_nested)</span>
<span class="muRecipe">def</span> main [
  <span class="Constant">1</span>:address:array:character<span class="Special"> &lt;- </span>copy [abc [def]]
]
<span class="traceContains">+parse:   ingredient: {&quot;abc [def]&quot;: &quot;literal-string&quot;}</span>

<span class="Delimiter">:(scenario string_literal_escaped)</span>
<span class="muRecipe">def</span> main [
  <span class="Constant">1</span>:address:array:character<span class="Special"> &lt;- </span>copy [abc \[def]
]
<span class="traceContains">+parse:   ingredient: {&quot;abc [def&quot;: &quot;literal-string&quot;}</span>

<span class="Delimiter">:(scenario string_literal_escaped_twice)</span>
<span class="muRecipe">def</span> main [
  <span class="Constant">1</span>:address:array:character<span class="Special"> &lt;- </span>copy [
abc \\[def]
]
<span class="traceContains">+parse:   ingredient: {&quot;\nabc \[def&quot;: &quot;literal-string&quot;}</span>

<span class="Delimiter">:(scenario string_literal_and_comment)</span>
<span class="muRecipe">def</span> main [
  <span class="Constant">1</span>:address:array:character<span class="Special"> &lt;- </span>copy [abc]  <span class="Comment"># comment</span>
]
<span class="traceContains">+parse: --- defining main</span>
<span class="traceContains">+parse: instruction: copy</span>
<span class="traceContains">+parse:   number of ingredients: 1</span>
<span class="traceContains">+parse:   ingredient: {&quot;abc&quot;: &quot;literal-string&quot;}</span>
<span class="traceContains">+parse:   product: {1: (&quot;address&quot; &quot;array&quot; &quot;character&quot;)}</span>

<span class="Delimiter">:(scenario string_literal_escapes_newlines_in_trace)</span>
<span class="muRecipe">def</span> main [
  copy [abc
<span class="muRecipe">def</span>]
]
<span class="traceContains">+parse:   ingredient: {&quot;abc\ndef&quot;: &quot;literal-string&quot;}</span>

<span class="Delimiter">:(scenario string_literal_can_skip_past_comments)</span>
<span class="muRecipe">def</span> main [
  copy [
    <span class="Comment"># ']' inside comment</span>
    bar
  ]
]
<span class="traceContains">+parse:   ingredient: {&quot;\n    # ']' inside comment\n    bar\n  &quot;: &quot;literal-string&quot;}</span>

<span class="Delimiter">:(scenario string_literal_empty)</span>
<span class="muRecipe">def</span> main [
  copy []
]
<span class="traceContains">+parse:   ingredient: {&quot;&quot;: &quot;literal-string&quot;}</span>

<span class="Delimiter">:(scenario multiple_unfinished_recipes)</span>
<span class="Special">% Hide_errors = true;</span>
<span class="muRecipe">def</span> f1 [
<span class="muRecipe">def</span> f2 [
<span class="traceContains">+error: unbalanced '['</span>
</pre>
</body>
</html>
<!-- vim: set foldmethod=manual : -->