about summary refs log tree commit diff stats
path: root/html/001help.cc.html
blob: d96f3fe6a563d5c139791dc65d7d334925746d1f (plain) (blame)
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
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
<!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 - 001help.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; }
.SalientComment { color: #00ffff; }
.Comment { color: #9090ff; }
.Delimiter { color: #800080; }
.cSpecial { color: #008000; }
.Identifier { color: #fcb165; }
.Normal { color: #eeeeee; background-color: #080808; padding-bottom: 1px; }
.PreProc { color: #800080; }
.CommentedCode { color: #6c6c6c; }
-->
</style>

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

-->
</script>
</head>
<body>
<pre id='vimCodeElement'>
<span class="Comment">//: Everything this project/binary supports.</span>
<span class="Comment">//: This should give you a sense for what to look forward to in later layers.</span>

<span class="Delimiter">:(before &quot;End Commandline Parsing&quot;)</span>
<span class="Normal">if</span> <span class="Delimiter">(</span>argc &lt;= <span class="Constant">1</span> || is_equal<span class="Delimiter">(</span>argv[<span class="Constant">1</span>]<span class="Delimiter">,</span> <span class="Constant">&quot;--help&quot;</span><span class="Delimiter">))</span> <span class="Delimiter">{</span>
  <span class="Comment">// this is the functionality later layers will provide</span>
  <span class="Comment">// currently no automated tests for commandline arg parsing</span>
  <span class="Normal">if</span> <span class="Delimiter">(</span>argc &lt;= <span class="Constant">1</span><span class="Delimiter">)</span> <span class="Delimiter">{</span>
    cerr &lt;&lt; <span class="Constant">&quot;Please provide a Mu program to run.</span><span class="cSpecial">\n</span><span class="Constant">&quot;</span>
         &lt;&lt; <span class="Constant">&quot;</span><span class="cSpecial">\n</span><span class="Constant">&quot;</span><span class="Delimiter">;</span>
  <span class="Delimiter">}</span>
  cerr &lt;&lt; <span class="Constant">&quot;Usage:</span><span class="cSpecial">\n</span><span class="Constant">&quot;</span>
       &lt;&lt; <span class="Constant">&quot;  mu [options] [test] [files]</span><span class="cSpecial">\n</span><span class="Constant">&quot;</span>
       &lt;&lt; <span class="Constant">&quot;or:</span><span class="cSpecial">\n</span><span class="Constant">&quot;</span>
       &lt;&lt; <span class="Constant">&quot;  mu [options] [test] [files] -- [ingredients for function/recipe 'main']</span><span class="cSpecial">\n</span><span class="Constant">&quot;</span>
       &lt;&lt; <span class="Constant">&quot;Square brackets surround optional arguments.</span><span class="cSpecial">\n</span><span class="Constant">&quot;</span>
       &lt;&lt; <span class="Constant">&quot;</span><span class="cSpecial">\n</span><span class="Constant">&quot;</span>
       &lt;&lt; <span class="Constant">&quot;Examples:</span><span class="cSpecial">\n</span><span class="Constant">&quot;</span>
       &lt;&lt; <span class="Constant">&quot;  To load files and run 'main':</span><span class="cSpecial">\n</span><span class="Constant">&quot;</span>
       &lt;&lt; <span class="Constant">&quot;    mu file1.mu file2.mu ...</span><span class="cSpecial">\n</span><span class="Constant">&quot;</span>
       &lt;&lt; <span class="Constant">&quot;  To run all tests:</span><span class="cSpecial">\n</span><span class="Constant">&quot;</span>
       &lt;&lt; <span class="Constant">&quot;    mu test</span><span class="cSpecial">\n</span><span class="Constant">&quot;</span>
       &lt;&lt; <span class="Constant">&quot;  To load files and then run all tests:</span><span class="cSpecial">\n</span><span class="Constant">&quot;</span>
       &lt;&lt; <span class="Constant">&quot;    mu test file1.mu file2.mu ...</span><span class="cSpecial">\n</span><span class="Constant">&quot;</span>
       &lt;&lt; <span class="Constant">&quot;  To load files and run only the tests in explicitly loaded files (for apps):</span><span class="cSpecial">\n</span><span class="Constant">&quot;</span>
       &lt;&lt; <span class="Constant">&quot;    mu --test-only-app test file1.mu file2.mu ...</span><span class="cSpecial">\n</span><span class="Constant">&quot;</span>
       &lt;&lt; <span class="Constant">&quot;  To load all files with a numeric prefix in a directory:</span><span class="cSpecial">\n</span><span class="Constant">&quot;</span>
       &lt;&lt; <span class="Constant">&quot;    mu directory1 directory2 ...</span><span class="cSpecial">\n</span><span class="Constant">&quot;</span>
       &lt;&lt; <span class="Constant">&quot;  You can test directories just like files.</span><span class="cSpecial">\n</span><span class="Constant">&quot;</span>
       &lt;&lt; <span class="Constant">&quot;    mu test directory1 directory2 ...</span><span class="cSpecial">\n</span><span class="Constant">&quot;</span>
       &lt;&lt; <span class="Constant">&quot;  To pass ingredients to a mu program, provide them after '--':</span><span class="cSpecial">\n</span><span class="Constant">&quot;</span>
       &lt;&lt; <span class="Constant">&quot;    mu file_or_dir1 file_or_dir2 ... -- ingredient1 ingredient2 ...</span><span class="cSpecial">\n</span><span class="Constant">&quot;</span>
       &lt;&lt; <span class="Constant">&quot;</span><span class="cSpecial">\n</span><span class="Constant">&quot;</span>
       &lt;&lt; <span class="Constant">&quot;  To browse a trace generated by a previous run:</span><span class="cSpecial">\n</span><span class="Constant">&quot;</span>
       &lt;&lt; <span class="Constant">&quot;    mu browse-trace file</span><span class="cSpecial">\n</span><span class="Constant">&quot;</span>
       <span class="Delimiter">;</span>
  <span class="Identifier">return</span> <span class="Constant">0</span><span class="Delimiter">;</span>
<span class="Delimiter">}</span>

<span class="Comment">//: Support for option parsing.</span>
<span class="Comment">//: Options always begin with '--' and are always the first arguments. An</span>
<span class="Comment">//: option will never follow a non-option.</span>
<span class="Delimiter">:(before &quot;End Commandline Parsing&quot;)</span>
<span class="Normal">char</span>** arg = &amp;argv[<span class="Constant">1</span>]<span class="Delimiter">;</span>
<span class="Normal">while</span> <span class="Delimiter">(</span>argc &gt; <span class="Constant">1</span> &amp;&amp; starts_with<span class="Delimiter">(</span>*arg<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><span class="Constant">false</span><span class="Delimiter">)</span>
    <span class="Delimiter">;</span>  <span class="Comment">// no-op branch just so any further additions can consistently always start with 'else'</span>
  <span class="Comment">// End Commandline Options(*arg)</span>
  <span class="Normal">else</span>
    cerr &lt;&lt; <span class="Constant">&quot;skipping unknown option &quot;</span> &lt;&lt; *arg &lt;&lt; <span class="cSpecial">'\n'</span><span class="Delimiter">;</span>
  --argc<span class="Delimiter">;</span> ++argv<span class="Delimiter">;</span> ++arg<span class="Delimiter">;</span>
<span class="Delimiter">}</span>

<span class="SalientComment">//:: Helper function used by the above fragment of code (and later layers too,</span>
<span class="SalientComment">//:: who knows?).</span>
<span class="Comment">//: The :(code) directive appends function definitions to the end of the</span>
<span class="Comment">//: project. Regardless of where functions are defined, we can call them</span>
<span class="Comment">//: anywhere we like as long as we format the function header in a specific</span>
<span class="Comment">//: way: put it all on a single line without indent, end the line with ') {'</span>
<span class="Comment">//: and no trailing whitespace. As long as functions uniformly start this</span>
<span class="Comment">//: way, our makefile contains a little command to automatically generate</span>
<span class="Comment">//: declarations for them.</span>
<span class="Delimiter">:(code)</span>
<span class="Normal">bool</span> is_equal<span class="Delimiter">(</span><span class="Normal">char</span>* s<span class="Delimiter">,</span> <span class="Normal">const</span> <span class="Normal">char</span>* lit<span class="Delimiter">)</span> <span class="Delimiter">{</span>
  <span class="Identifier">return</span> strncmp<span class="Delimiter">(</span>s<span class="Delimiter">,</span> lit<span class="Delimiter">,</span> strlen<span class="Delimiter">(</span>lit<span class="Delimiter">))</span> == <span class="Constant">0</span><span class="Delimiter">;</span>
<span class="Delimiter">}</span>

<span class="Normal">bool</span> starts_with<span class="Delimiter">(</span><span class="Normal">const</span> string&amp; s<span class="Delimiter">,</span> <span class="Normal">const</span> string&amp; pat<span class="Delimiter">)</span> <span class="Delimiter">{</span>
  string::const_iterator a=s<span class="Delimiter">.</span>begin<span class="Delimiter">(),</span> b=pat<span class="Delimiter">.</span>begin<span class="Delimiter">();</span>
  <span class="Normal">for</span> <span class="Delimiter">(</span><span class="Comment">/*</span><span class="Comment">nada</span><span class="Comment">*/</span><span class="Delimiter">;</span> a!=s<span class="Delimiter">.</span>end<span class="Delimiter">()</span> &amp;&amp; b!=pat<span class="Delimiter">.</span>end<span class="Delimiter">();</span> ++a<span class="Delimiter">,</span> ++b<span class="Delimiter">)</span>
    <span class="Normal">if</span> <span class="Delimiter">(</span>*a != *b<span class="Delimiter">)</span> <span class="Identifier">return</span> <span class="Constant">false</span><span class="Delimiter">;</span>
  <span class="Identifier">return</span> b == pat<span class="Delimiter">.</span>end<span class="Delimiter">();</span>
<span class="Delimiter">}</span>

<span class="Comment">//: I'll throw some style conventions here for want of a better place for them.</span>
<span class="Comment">//: As a rule I hate style guides. Do what you want, that's my motto. But since</span>
<span class="Comment">//: we're dealing with C/C++, the one big thing we want to avoid is undefined</span>
<span class="Comment">//: behavior. If a compiler ever encounters undefined behavior it can make</span>
<span class="Comment">//: your program do anything it wants.</span>
<span class="Comment">//:</span>
<span class="Comment">//: For reference, my checklist of undefined behaviors to watch out for:</span>
<span class="Comment">//:   out-of-bounds access</span>
<span class="Comment">//:   uninitialized variables</span>
<span class="Comment">//:   use after free</span>
<span class="Comment">//:   dereferencing invalid pointers: null, a new of size 0, others</span>
<span class="Comment">//:</span>
<span class="Comment">//:   casting a large number to a type too small to hold it</span>
<span class="Comment">//:</span>
<span class="Comment">//:   integer overflow</span>
<span class="Comment">//:   division by zero and other undefined expressions</span>
<span class="Comment">//:   left-shift by negative count</span>
<span class="Comment">//:   shifting values by more than or equal to the number of bits they contain</span>
<span class="Comment">//:   bitwise operations on signed numbers</span>
<span class="Comment">//:</span>
<span class="Comment">//:   Converting pointers to types of different alignment requirements</span>
<span class="Comment">//:     T* -&gt; void* -&gt; T*: defined</span>
<span class="Comment">//:     T* -&gt; U* -&gt; T*: defined if non-function pointers and alignment requirements are same</span>
<span class="Comment">//:     function pointers may be cast to other function pointers</span>
<span class="Comment">//:</span>
<span class="Comment">//:       Casting a numeric value into a value that can't be represented by the target type (either directly or via static_cast)</span>
<span class="Comment">//:</span>
<span class="Comment">//: To guard against these, some conventions:</span>
<span class="Comment">//:</span>
<span class="Comment">//: 0. Initialize all primitive variables in functions and constructors.</span>
<span class="Comment">//:</span>
<span class="Comment">//: 1. Minimize use of pointers and pointer arithmetic. Avoid 'new' and</span>
<span class="Comment">//: 'delete' as far as possible. Rely on STL to perform memory management to</span>
<span class="Comment">//: avoid use-after-free issues (and memory leaks).</span>
<span class="Comment">//:</span>
<span class="Comment">//: 2. Avoid naked arrays to avoid out-of-bounds access. Never use operator[]</span>
<span class="Comment">//: except with map. Use at() with STL vectors and so on.</span>
<span class="Comment">//:</span>
<span class="Comment">//: 3. Valgrind all the things.</span>
<span class="Comment">//:</span>
<span class="Comment">//: 4. Avoid unsigned numbers. Not strictly an undefined-behavior issue, but</span>
<span class="Comment">//: the extra range doesn't matter, and it's one less confusing category of</span>
<span class="Comment">//: interaction gotchas to worry about.</span>
<span class="Comment">//:</span>
<span class="Comment">//: Corollary: don't use the size() method on containers, since it returns an</span>
<span class="Comment">//: unsigned and that'll cause warnings about mixing signed and unsigned,</span>
<span class="Comment">//: yadda-yadda. Instead use this macro below to perform an unsafe cast to</span>
<span class="Comment">//: signed. We'll just give up immediately if a container's ever too large.</span>
<span class="Comment">//: Basically, Mu is not concerned about this being a little slower than it</span>
<span class="Comment">//: could be. (<a href="https://gist.github.com/rygorous/e0f055bfb74e3d5f0af20690759de5a7)">https://gist.github.com/rygorous/e0f055bfb74e3d5f0af20690759de5a7)</a></span>
<span class="Comment">//:</span>
<span class="Comment">//: Addendum to corollary: We're going to uniformly use int everywhere, to</span>
<span class="Comment">//: indicate that we're oblivious to number size, and since Clang on 32-bit</span>
<span class="Comment">//: platforms doesn't yet support multiplication over 64-bit integers, and</span>
<span class="Comment">//: since multiplying two integers seems like a more common situation to end</span>
<span class="Comment">//: up in than integer overflow.</span>
<span class="Delimiter">:(before &quot;End Includes&quot;)</span>
<span class="PreProc">#define SIZE(X) (assert((X)</span><span class="Delimiter">.</span><span class="PreProc">size() &lt; (</span><span class="Constant">1LL</span><span class="PreProc">&lt;&lt;(</span><span class="Normal">sizeof</span><span class="PreProc">(</span><span class="Normal">int</span><span class="PreProc">)*</span><span class="Constant">8</span><span class="PreProc">-</span><span class="Constant">2</span><span class="PreProc">)))</span><span class="Delimiter">,</span><span class="PreProc"> </span><span class="Normal">static_cast</span><span class="PreProc">&lt;</span><span class="Normal">int</span><span class="PreProc">&gt;((X)</span><span class="Delimiter">.</span><span class="PreProc">size()))</span>

<span class="Comment">//: 5. Integer overflow is guarded against at runtime using the -ftrapv flag</span>
<span class="Comment">//: to the compiler, supported by Clang (GCC version only works sometimes:</span>
<span class="Comment">//: <a href="http://stackoverflow.com/questions/20851061/how-to-make-gcc-ftrapv-work).">http://stackoverflow.com/questions/20851061/how-to-make-gcc-ftrapv-work).</a></span>
<span class="Delimiter">:(before &quot;atexit(teardown)&quot;)</span>
initialize_signal_handlers<span class="Delimiter">();</span>  <span class="Comment">// not always necessary, but doesn't hurt</span>
<span class="CommentedCode">//? cerr &lt;&lt; INT_MAX+1 &lt;&lt; '\n';  // test overflow</span>
<span class="CommentedCode">//? assert(false);  // test SIGABRT</span>
<span class="Delimiter">:(code)</span>
<span class="Comment">// based on <a href="https://spin.atomicobject.com/2013/01/13/exceptions-stack-traces-c">https://spin.atomicobject.com/2013/01/13/exceptions-stack-traces-c</a></span>
<span class="Normal">void</span> initialize_signal_handlers<span class="Delimiter">()</span> <span class="Delimiter">{</span>
  <span class="Normal">struct</span> sigaction action<span class="Delimiter">;</span>
  bzero<span class="Delimiter">(</span>&amp;action<span class="Delimiter">,</span> <span class="Normal">sizeof</span><span class="Delimiter">(</span>action<span class="Delimiter">));</span>
  action<span class="Delimiter">.</span>sa_sigaction = dump_and_exit<span class="Delimiter">;</span>
  sigemptyset<span class="Delimiter">(</span>&amp;action<span class="Delimiter">.</span>sa_mask<span class="Delimiter">);</span>
  sigaction<span class="Delimiter">(</span><span class="Constant">SIGABRT</span><span class="Delimiter">,</span> &amp;action<span class="Delimiter">,</span> <span class="Constant">NULL</span><span class="Delimiter">);</span>  <span class="Comment">// assert() failure or integer overflow on linux (with -ftrapv)</span>
  sigaction<span class="Delimiter">(</span><span class="Constant">SIGILL</span><span class="Delimiter">,</span>  &amp;action<span class="Delimiter">,</span> <span class="Constant">NULL</span><span class="Delimiter">);</span>  <span class="Comment">// integer overflow on OS X (with -ftrapv)</span>
<span class="Delimiter">}</span>
<span class="Normal">void</span> dump_and_exit<span class="Delimiter">(</span><span class="Normal">int</span> sig<span class="Delimiter">,</span> unused siginfo_t* dummy1<span class="Delimiter">,</span> unused <span class="Normal">void</span>* dummy2<span class="Delimiter">)</span> <span class="Delimiter">{</span>
  <span class="Normal">switch</span> <span class="Delimiter">(</span>sig<span class="Delimiter">)</span> <span class="Delimiter">{</span>
    <span class="Normal">case</span> <span class="Constant">SIGABRT</span>:
<span class="PreProc">      #ifndef __APPLE__</span>
        cerr &lt;&lt; <span class="Constant">&quot;SIGABRT: might be an integer overflow if it wasn't an assert() failure</span><span class="cSpecial">\n</span><span class="Constant">&quot;</span><span class="Delimiter">;</span>
        _Exit<span class="Delimiter">(</span><span class="Constant">1</span><span class="Delimiter">);</span>
<span class="PreProc">      #endif</span>
      <span class="Identifier">break</span><span class="Delimiter">;</span>
    <span class="Normal">case</span> <span class="Constant">SIGILL</span>:
<span class="PreProc">      #ifdef __APPLE__</span>
        cerr &lt;&lt; <span class="Constant">&quot;SIGILL: most likely caused by integer overflow</span><span class="cSpecial">\n</span><span class="Constant">&quot;</span><span class="Delimiter">;</span>
        _Exit<span class="Delimiter">(</span><span class="Constant">1</span><span class="Delimiter">);</span>
<span class="PreProc">      #endif</span>
      <span class="Identifier">break</span><span class="Delimiter">;</span>
    <span class="Normal">default</span>:
      <span class="Identifier">break</span><span class="Delimiter">;</span>
  <span class="Delimiter">}</span>
<span class="Delimiter">}</span>
<span class="Delimiter">:(before &quot;End Includes&quot;)</span>
<span class="PreProc">#include </span><span class="Constant">&lt;signal.h&gt;</span>

<span class="Comment">//: For good measure we'll also enable SIGFPE.</span>
<span class="Delimiter">:(before &quot;atexit(teardown)&quot;)</span>
feenableexcept<span class="Delimiter">(</span>FE_OVERFLOW | FE_UNDERFLOW<span class="Delimiter">);</span>
<span class="CommentedCode">//? assert(sizeof(int) == 4 &amp;&amp; sizeof(float) == 4);</span>
<span class="CommentedCode">//? //                          | exp   |  mantissa</span>
<span class="CommentedCode">//? int smallest_subnormal = 0b00000000000000000000000000000001;</span>
<span class="CommentedCode">//? float smallest_subnormal_f = *reinterpret_cast&lt;float*&gt;(&amp;smallest_subnormal);</span>
<span class="CommentedCode">//? cerr &lt;&lt; &quot;ε: &quot; &lt;&lt; smallest_subnormal_f &lt;&lt; '\n';</span>
<span class="CommentedCode">//? cerr &lt;&lt; &quot;ε/2: &quot; &lt;&lt; smallest_subnormal_f/2 &lt;&lt; &quot; (underflow)\n&quot;;  // test SIGFPE</span>
<span class="Delimiter">:(before &quot;End Includes&quot;)</span>
<span class="PreProc">#include </span><span class="Constant">&lt;fenv.h&gt;</span>
<span class="Delimiter">:(code)</span>
<span class="PreProc">#ifdef __APPLE__</span>
<span class="Comment">// Public domain polyfill for feenableexcept on OS X</span>
<span class="Comment">// <a href="http://www-personal.umich.edu/~williams/archive/computation/fe-handling-example.c">http://www-personal.umich.edu/~williams/archive/computation/fe-handling-example.c</a></span>
<span class="Normal">int</span> feenableexcept <span class="Delimiter">(</span><span class="Normal">unsigned</span> <span class="Normal">int</span> excepts<span class="Delimiter">)</span> <span class="Delimiter">{</span>
  <span class="Normal">static</span> fenv_t fenv<span class="Delimiter">;</span>
  <span class="Normal">unsigned</span> <span class="Normal">int</span> new_excepts = excepts &amp; FE_ALL_EXCEPT<span class="Delimiter">;</span>
  <span class="Normal">unsigned</span> <span class="Normal">int</span> old_excepts<span class="Delimiter">;</span>
  <span class="Normal">if</span> <span class="Delimiter">(</span>fegetenv<span class="Delimiter">(</span>&amp;fenv<span class="Delimiter">))</span> <span class="Identifier">return</span> -<span class="Constant">1</span><span class="Delimiter">;</span>
  old_excepts = fenv<span class="Delimiter">.</span>__control &amp; FE_ALL_EXCEPT<span class="Delimiter">;</span>
  fenv<span class="Delimiter">.</span>__control &amp;= ~new_excepts<span class="Delimiter">;</span>
  fenv<span class="Delimiter">.</span>__mxcsr   &amp;= ~<span class="Delimiter">(</span>new_excepts &lt;&lt; <span class="Constant">7</span><span class="Delimiter">);</span>
  <span class="Identifier">return</span> fesetenv<span class="Delimiter">(</span>&amp;fenv<span class="Delimiter">)</span> ? -<span class="Constant">1</span> : old_excepts<span class="Delimiter">;</span>
<span class="Delimiter">}</span>
<span class="PreProc">#endif</span>

<span class="Comment">//: 6. Map's operator[] being non-const is fucking evil.</span>
<span class="Delimiter">:(before &quot;Globals&quot;)</span>  <span class="Comment">// can't generate prototypes for these</span>
<span class="Comment">// from <a href="http://stackoverflow.com/questions/152643/idiomatic-c-for-reading-from-a-const-map">http://stackoverflow.com/questions/152643/idiomatic-c-for-reading-from-a-const-map</a></span>
<span class="Normal">template</span>&lt;<span class="Normal">typename</span> T&gt; <span class="Normal">typename</span> T::mapped_type&amp; get<span class="Delimiter">(</span>T&amp; map<span class="Delimiter">,</span> <span class="Normal">typename</span> T::key_type <span class="Normal">const</span>&amp; key<span class="Delimiter">)</span> <span class="Delimiter">{</span>
  <span class="Normal">typename</span> T::iterator iter<span class="Delimiter">(</span>map<span class="Delimiter">.</span>find<span class="Delimiter">(</span>key<span class="Delimiter">));</span>
  assert<span class="Delimiter">(</span>iter != map<span class="Delimiter">.</span>end<span class="Delimiter">());</span>
  <span class="Identifier">return</span> iter<span class="Delimiter">-&gt;</span>second<span class="Delimiter">;</span>
<span class="Delimiter">}</span>
<span class="Normal">template</span>&lt;<span class="Normal">typename</span> T&gt; <span class="Normal">typename</span> T::mapped_type <span class="Normal">const</span>&amp; get<span class="Delimiter">(</span><span class="Normal">const</span> T&amp; map<span class="Delimiter">,</span> <span class="Normal">typename</span> T::key_type <span class="Normal">const</span>&amp; key<span class="Delimiter">)</span> <span class="Delimiter">{</span>
  <span class="Normal">typename</span> T::const_iterator iter<span class="Delimiter">(</span>map<span class="Delimiter">.</span>find<span class="Delimiter">(</span>key<span class="Delimiter">));</span>
  assert<span class="Delimiter">(</span>iter != map<span class="Delimiter">.</span>end<span class="Delimiter">());</span>
  <span class="Identifier">return</span> iter<span class="Delimiter">-&gt;</span>second<span class="Delimiter">;</span>
<span class="Delimiter">}</span>
<span class="Normal">template</span>&lt;<span class="Normal">typename</span> T&gt; <span class="Normal">typename</span> T::mapped_type <span class="Normal">const</span>&amp; put<span class="Delimiter">(</span>T&amp; map<span class="Delimiter">,</span> <span class="Normal">typename</span> T::key_type <span class="Normal">const</span>&amp; key<span class="Delimiter">,</span> <span class="Normal">typename</span> T::mapped_type <span class="Normal">const</span>&amp; value<span class="Delimiter">)</span> <span class="Delimiter">{</span>
  map[key] = value<span class="Delimiter">;</span>
  <span class="Identifier">return</span> map[key]<span class="Delimiter">;</span>
<span class="Delimiter">}</span>
<span class="Normal">template</span>&lt;<span class="Normal">typename</span> T&gt; <span class="Normal">bool</span> contains_key<span class="Delimiter">(</span>T&amp; map<span class="Delimiter">,</span> <span class="Normal">typename</span> T::key_type <span class="Normal">const</span>&amp; key<span class="Delimiter">)</span> <span class="Delimiter">{</span>
  <span class="Identifier">return</span> map<span class="Delimiter">.</span>find<span class="Delimiter">(</span>key<span class="Delimiter">)</span> != map<span class="Delimiter">.</span>end<span class="Delimiter">();</span>
<span class="Delimiter">}</span>
<span class="Normal">template</span>&lt;<span class="Normal">typename</span> T&gt; <span class="Normal">typename</span> T::mapped_type&amp; get_or_insert<span class="Delimiter">(</span>T&amp; map<span class="Delimiter">,</span> <span class="Normal">typename</span> T::key_type <span class="Normal">const</span>&amp; key<span class="Delimiter">)</span> <span class="Delimiter">{</span>
  <span class="Identifier">return</span> map[key]<span class="Delimiter">;</span>
<span class="Delimiter">}</span>
<span class="Comment">//: The contract: any container that relies on get_or_insert should never call</span>
<span class="Comment">//: contains_key.</span>

<span class="Comment">//: 7. istreams are a royal pain in the arse. You have to be careful about</span>
<span class="Comment">//: what subclass you try to putback into. You have to watch out for the pesky</span>
<span class="Comment">//: failbit and badbit. Just avoid eof() and use this helper instead.</span>
<span class="Delimiter">:(code)</span>
<span class="Normal">bool</span> has_data<span class="Delimiter">(</span>istream&amp; in<span class="Delimiter">)</span> <span class="Delimiter">{</span>
  <span class="Identifier">return</span> in &amp;&amp; !in<span class="Delimiter">.</span>eof<span class="Delimiter">();</span>
<span class="Delimiter">}</span>

<span class="Delimiter">:(before &quot;End Includes&quot;)</span>
<span class="PreProc">#include </span><span class="Constant">&lt;assert.h&gt;</span>

<span class="PreProc">#include </span><span class="Constant">&lt;iostream&gt;</span>
<span class="Normal">using</span> std::istream<span class="Delimiter">;</span>
<span class="Normal">using</span> std::ostream<span class="Delimiter">;</span>
<span class="Normal">using</span> std::iostream<span class="Delimiter">;</span>
<span class="Normal">using</span> std::cin<span class="Delimiter">;</span>
<span class="Normal">using</span> std::cout<span class="Delimiter">;</span>
<span class="Normal">using</span> std::cerr<span class="Delimiter">;</span>
<span class="PreProc">#include </span><span class="Constant">&lt;iomanip&gt;</span>

<span class="PreProc">#include </span><span class="Constant">&lt;string.h&gt;</span>
<span class="PreProc">#include </span><span class="Constant">&lt;string&gt;</span>
<span class="Normal">using</span> std::string<span class="Delimiter">;</span>

<span class="PreProc">#define unused  __attribute__((unused))</span>
</pre>
</body>
</html>
<!-- vim: set foldmethod=manual : -->